fix: make code java 11 compatible

build: fix build script to exit with code when error occurs
Merge pull request #9 from TopchetoEU/TopchetoEU/perms-and-fs
2023-11-25 20:22:16 +02:00 · 2023-11-25 20:16:06 +02:00 · 2023-11-25 20:10:59 +02:00 · 2023-11-25 20:09:59 +02:00 · 2023-11-25 20:09:47 +02:00 · 2023-11-25 19:36:18 +02:00
139 changed files with 6633 additions and 2507 deletions
--- a/.github/workflows/tagged-release.yml
+++ b/.github/workflows/tagged-release.yml
@@ -11,6 +11,11 @@ jobs:
    runs-on: "ubuntu-latest"

    steps:
+      - name: Setup Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'adopt'
+          java-version: '11'
      - name: Clone repository
        uses: GuillaumeFalourd/clone-github-repo-action@main
        with:
--- a/README.md
+++ b/README.md
@@ -4,31 +4,42 @@

 **WARNING: Currently, this code is mostly undocumented. Proceed with caution and a psychiatrist.**

-JScript is an engine, capable of running EcmaScript 5, written entirely in Java. This engine has been developed with the goal of being easy to integrate with your preexisting codebase, **THE GOAL OF THIS ENGINE IS NOT PERFORMANCE**. My crude experiments show that this engine is 50x-100x slower than V8, which, although bad, is acceptable for most simple scripting purposes.
+JScript is an engine, capable of running EcmaScript 5, written entirely in Java. This engine has been developed with the goal of being easy to integrate with your preexisting codebase, **THE GOAL OF THIS ENGINE IS NOT PERFORMANCE**. My crude experiments show that this engine is 50x-100x slower than V8, which, although bad, is acceptable for most simple scripting purposes. Note that although the codebase has a Main class, this isn't meant to be a standalone program, but instead a library for running JavaScript code.

 ## Example

 The following will create a REPL using the engine as a backend. Not that this won't properly log errors. I recommend checking out the implementation in `Main.main`:

 ```java
-var engine = new PolyfillEngine(new File("."));
-var in = new BufferedReader(new InputStreamReader(System.in));
+var engine = new Engine(true /* false if you dont want debugging */);
+var env = new Environment(null, null, null);
+var debugger = new DebugServer();
+
+// Create one target for the engine and start debugging server
+debugger.targets.put("target", (socket, req) -> new SimpleDebugger(socket, engine));
+debugger.start(new InetSocketAddress("127.0.0.1", 9229), true);
+
+// Queue code to load internal libraries and start engine
+engine.pushMsg(false, null, new Internals().getApplier(env));
 engine.start();

 while (true) {
    try {
-        var raw = in.readLine();
+        var raw = Reading.read();
+        if (raw == null) break;

-        var res = engine.pushMsg(false, engine.global(), Map.of(), "<stdio>", raw, null).await();
-        Values.printValue(engine.context(), res);
-        System.out.println();
+        // Push a message to the engine with the raw REPL code
+        var res = engine.pushMsg(
+            false, new Context(engine).pushEnv(env),
+            new Filename("jscript", "repl.js"), raw, null
+        ).await();
+
+        Values.printValue(null, res);
    }
-    catch (EngineException e) {
-        try {
-            System.out.println("Uncaught " + e.toString(engine.context()));
-        }
-        catch (InterruptedException _e) {  return; }
+    catch (EngineException e) { Values.printError(e, ""); }
+    catch (SyntaxException ex) {
+        System.out.println("Syntax error:" + ex.msg);
    }
-    catch (IOException | InterruptedException e) { return; }
+    catch (IOException e) { }
 }
 ```
--- a/build.js
+++ b/build.js
@@ -1,7 +1,7 @@
 const { spawn } = require('child_process');
 const fs = require('fs/promises');
 const pt = require('path');
-const { argv } = require('process');
+const { argv, exit } = require('process');

 const conf = {
    name: "java-jscript",
@@ -74,6 +74,7 @@ async function compileJava() {
    }
    catch (e) {
        if (argv[2] === 'debug') throw e;
-        else console.log(e.toString());
+        console.log(e.toString());
+        exit(-1);
    }
 })();
--- a/src/assets/favicon.png
+++ b/src/assets/favicon.png
--- a/src/assets/index.html
+++ b/src/assets/index.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>JScript Debugger</title>
+</head>
+<body>
+    <p>
+        This is the debugger of JScript. It implement the <a href="https://chromedevtools.github.io/devtools-protocol/1-2/">V8 Debugging protocol</a>,
+        so you can use the devtools in chrome. <br>
+        The debugger is still in early development, so please report any issues to
+        <a href="https://github.com/TopchetoEU/java-jscript/issues">the github repo</a>.
+    </p>
+
+    <p>
+        Here are the available entrypoints:
+        <ul>
+            <li><a href="json/version">/json/version</a> - version and other stuff about the JScript engine</li>
+            <li><a href="json/list">/json/list</a> - a list of all entrypoints</li>
+            <li><a href="json/protocol">/json/protocol</a> - documentation of the implemented V8 protocol</li>
+            <li>/(any target) - websocket entrypoints for debugging</li>
+        </ul>
+    </p>
+
+    <p>
+        Running ${NAME} v${VERSION} by ${AUTHOR}
+    </p>
+</body>
+</html>
--- a/src/assets/protocol.json
+++ b/src/assets/protocol.json
--- a/src/me/topchetoeu/jscript/Filename.java
+++ b/src/me/topchetoeu/jscript/Filename.java
@@ -0,0 +1,60 @@
+package me.topchetoeu.jscript;
+
+import java.io.File;
+
+public class Filename {
+    public final String protocol;
+    public final String path;
+
+    public String toString() {
+        return protocol + "://" + path;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + protocol.hashCode();
+        result = prime * result + path.hashCode();
+        return result;
+    }
+
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null) return false;
+        if (getClass() != obj.getClass()) return false;
+
+        var other = (Filename) obj;
+
+        if (protocol == null) {
+            if (other.protocol != null) return false;
+        }
+        else if (!protocol.equals(other.protocol)) return false;
+
+        if (path == null) {
+            if (other.path != null) return false;
+        }
+        else if (!path.equals(other.path)) return false;
+        return true;
+    }
+
+    public static Filename fromFile(File file) {
+        return new Filename("file", file.getAbsolutePath());
+    }
+
+
+    public Filename(String protocol, String path) {
+        path = path.trim();
+        protocol = protocol.trim();
+        this.protocol = protocol;
+        this.path = path;
+    }
+
+    public static Filename parse(String val) {
+        var i = val.indexOf("://");
+        if (i >= 0) return new Filename(val.substring(0, i).trim(), val.substring(i + 3).trim());
+        else return new Filename("file", val.trim());
+    }
+}
--- a/src/me/topchetoeu/jscript/Location.java
+++ b/src/me/topchetoeu/jscript/Location.java
@@ -1,18 +1,18 @@
 package me.topchetoeu.jscript;

-public class Location {
-    public static final Location INTERNAL = new Location(0, 0, "<internal>");
+public class Location implements Comparable<Location> {
+    public static final Location INTERNAL = new Location(0, 0, new Filename("jscript", "native"));
    private int line;
    private int start;
-    private String filename;
+    private Filename filename;

    public int line() { return line; }
    public int start() { return start; }
-    public String filename() { return filename; }
+    public Filename filename() { return filename; }

    @Override
    public String toString() {
-        return filename + ":" + line + ":" + start;
+        return filename.toString() + ":" + line + ":" + start;
    }

    public Location add(int n, boolean clone) {
@@ -55,7 +55,18 @@ public class Location {
        return true;
    }

-    public Location(int line, int start, String filename) {
+    @Override
+    public int compareTo(Location other) {
+        int a = filename.toString().compareTo(other.filename.toString());
+        int b = Integer.compare(line, other.line);
+        int c = Integer.compare(start, other.start);
+
+        if (a != 0) return a;
+        if (b != 0) return b;
+        return c;
+    }
+
+    public Location(int line, int start, Filename filename) {
        this.line = line;
        this.start = start;
        this.filename = filename;
--- a/src/me/topchetoeu/jscript/Main.java
+++ b/src/me/topchetoeu/jscript/Main.java
@@ -1,129 +1,165 @@
-package me.topchetoeu.jscript;
-
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.nio.file.Files;
-import java.nio.file.Path;
-
-import me.topchetoeu.jscript.engine.Message;
-import me.topchetoeu.jscript.engine.Engine;
-import me.topchetoeu.jscript.engine.Environment;
-import me.topchetoeu.jscript.engine.values.NativeFunction;
-import me.topchetoeu.jscript.engine.values.Values;
-import me.topchetoeu.jscript.events.Observer;
-import me.topchetoeu.jscript.exceptions.EngineException;
-import me.topchetoeu.jscript.exceptions.SyntaxException;
-import me.topchetoeu.jscript.polyfills.Internals;
-
-public class Main {
-    static Thread task;
-    static Engine engine;
-    static Environment env;
-
-    public static String streamToString(InputStream in) {
-        try {
-            StringBuilder out = new StringBuilder();
-            BufferedReader br = new BufferedReader(new InputStreamReader(in));
-
-            for(var line = br.readLine(); line != null; line = br.readLine()) {
-                out.append(line).append('\n');
-            }
-
-            br.close();
-            return out.toString();
-        }
-        catch (IOException e) {
-            return null;
-        }
-    }
-    public static String resourceToString(String name) {
-        var str = Main.class.getResourceAsStream("/me/topchetoeu/jscript/" + name);
-        if (str == null) return null;
-        return streamToString(str);
-    }
-
-    private static Observer<Object> valuePrinter = new Observer<Object>() {
-        public void next(Object data) {
-            try { Values.printValue(null, data); }
-            catch (InterruptedException e) { }
-            System.out.println();
-        }
-
-        public void error(RuntimeException err) {
-            try { Values.printError(err, null); }
-            catch (InterruptedException ex) { return; }
-        }
-    };
-
-    public static void main(String args[]) {
-        System.out.println(String.format("Running %s v%s by %s", Metadata.NAME, Metadata.VERSION, Metadata.AUTHOR));
-        var in = new BufferedReader(new InputStreamReader(System.in));
-        engine = new Engine();
-
-        env = new Environment(null, null, null);
-        var exited = new boolean[1];
-
-        engine.pushMsg(false, new Message(engine), new NativeFunction((ctx, thisArg, _a) -> {
-            new Internals().apply(env);
-
-            env.global.define("exit", _ctx -> {
-                exited[0] = true;
-                task.interrupt();
-                throw new InterruptedException();
-            });
-            env.global.define("go", _ctx -> {
-                try {
-                    var func = _ctx.compile("do.js", new String(Files.readAllBytes(Path.of("do.js"))));
-                    return func.call(_ctx);
-                }
-                catch (IOException e) {
-                    throw new EngineException("Couldn't open do.js");
-                }
-            });
-
-            return null;
-        }), null);
-
-        task = engine.start();
-        var reader = new Thread(() -> {
-            try {
-                while (true) {
-                    try {
-                        var raw = in.readLine();
-
-                        if (raw == null) break;
-                        engine.pushMsg(false, env.context(new Message(engine)), "<stdio>", raw, null).toObservable().once(valuePrinter);
-                    }
-                    catch (EngineException e) {
-                        try {
-                            System.out.println("Uncaught " + e.toString(null));
-                        }
-                        catch (EngineException ex) {
-                            System.out.println("Uncaught [error while converting to string]");
-                        }
-                    }
-                }
-            }
-            catch (IOException e) {
-                e.printStackTrace();
-                return;
-            }
-            catch (SyntaxException ex) {
-                if (exited[0]) return;
-                System.out.println("Syntax error:" + ex.msg);
-            }
-            catch (RuntimeException ex) {
-                if (exited[0]) return;
-                System.out.println("Internal error ocurred:");
-                ex.printStackTrace();
-            }
-            catch (InterruptedException e) { return; }
-            if (exited[0]) return;
-        });
-        reader.setDaemon(true);
-        reader.setName("STD Reader");
-        reader.start();
-    }
-}
+package me.topchetoeu.jscript;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.Engine;
+import me.topchetoeu.jscript.engine.Environment;
+import me.topchetoeu.jscript.engine.debug.DebugServer;
+import me.topchetoeu.jscript.engine.debug.SimpleDebugger;
+import me.topchetoeu.jscript.engine.values.ArrayValue;
+import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.events.Observer;
+import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.exceptions.InterruptException;
+import me.topchetoeu.jscript.exceptions.SyntaxException;
+import me.topchetoeu.jscript.filesystem.MemoryFilesystem;
+import me.topchetoeu.jscript.filesystem.Mode;
+import me.topchetoeu.jscript.filesystem.PhysicalFilesystem;
+import me.topchetoeu.jscript.lib.Internals;
+
+public class Main {   
+    public static class Printer implements Observer<Object> {
+        public void next(Object data) {
+            Values.printValue(null, data);
+            System.out.println();
+        }
+
+        public void error(RuntimeException err) {
+            Values.printError(err, null);
+        }
+
+        public void finish() {
+            engineTask.interrupt();
+        }
+    }
+
+    static Thread engineTask, debugTask;
+    static Engine engine = new Engine(true);
+    static DebugServer debugServer = new DebugServer();
+    static Environment environment = new Environment(null, null, null);
+
+    static int j = 0;
+    static boolean exited = false;
+    static String[] args;
+
+    private static void reader() {
+        try {
+            for (var arg : args) {
+                try {
+                    if (arg.equals("--ts")) initTypescript();
+                    else {
+                        var file = Path.of(arg);
+                        var raw = Files.readString(file);
+                        var res = engine.pushMsg(
+                            false, new Context(engine, environment),
+                            Filename.fromFile(file.toFile()),
+                            raw, null
+                        ).await();
+                        Values.printValue(null, res);
+                        System.out.println();
+                    }
+                }
+                catch (EngineException e) { Values.printError(e, null); }
+            }
+            for (var i = 0; ; i++) {
+                try {
+                    var raw = Reading.read();
+
+                    if (raw == null) break;
+                    var res = engine.pushMsg(
+                        false, new Context(engine, environment),
+                        new Filename("jscript", "repl/" + i + ".js"),
+                        raw, null
+                    ).await();
+                    Values.printValue(null, res);
+                    System.out.println();
+                }
+                catch (EngineException e) { Values.printError(e, null); }
+                catch (SyntaxException e) { Values.printError(e, null); }
+            }
+        }
+        catch (IOException e) {
+            System.out.println(e.toString());
+            exited = true;
+        }
+        catch (RuntimeException ex) {
+            if (!exited) {
+                System.out.println("Internal error ocurred:");
+                ex.printStackTrace();
+            }
+        }
+        if (exited) {
+            debugTask.interrupt();
+            engineTask.interrupt();
+        }
+    }
+
+    private static void initEnv() {
+        environment = Internals.apply(environment);
+
+        environment.global.define("exit", _ctx -> {
+            exited = true;
+            throw new InterruptException();
+        });
+        environment.global.define("go", _ctx -> {
+            try {
+                var f = Path.of("do.js");
+                var func = _ctx.compile(new Filename("do", "do/" + j++ + ".js"), new String(Files.readAllBytes(f)));
+                return func.call(_ctx);
+            }
+            catch (IOException e) {
+                throw new EngineException("Couldn't open do.js");
+            }
+        });
+
+        environment.filesystem.protocols.put("temp", new MemoryFilesystem(Mode.READ_WRITE));
+        environment.filesystem.protocols.put("file", new PhysicalFilesystem(Path.of(".").toAbsolutePath()));
+    }
+    private static void initEngine() {
+        debugServer.targets.put("target", (ws, req) -> new SimpleDebugger(ws, engine));
+        engineTask = engine.start();
+        debugTask = debugServer.start(new InetSocketAddress("127.0.0.1", 9229), true);
+    }
+    private static void initTypescript() {
+        try {
+            var tsEnv = Internals.apply(new Environment(null, null, null));
+            var bsEnv = Internals.apply(new Environment(null, null, null));
+
+            engine.pushMsg(
+                false, new Context(engine, tsEnv),
+                new Filename("jscript", "ts.js"),
+                Reading.resourceToString("js/ts.js"), null
+            ).await();
+            System.out.println("Loaded typescript!");
+
+            var ctx = new Context(engine, bsEnv);
+
+            engine.pushMsg(
+                false, ctx,
+                new Filename("jscript", "internals/bootstrap.js"), Reading.resourceToString("js/bootstrap.js"), null,
+                tsEnv.global.get(ctx, "ts"), environment, new ArrayValue(null, Reading.resourceToString("js/lib.d.ts"))
+            ).await();
+        }
+        catch (EngineException e) {
+            Values.printError(e, "(while initializing TS)");
+        }
+    }
+
+    public static void main(String args[]) {
+        System.out.println(String.format("Running %s v%s by %s", Metadata.name(), Metadata.version(), Metadata.author()));
+
+        Main.args = args;
+        var reader = new Thread(Main::reader);
+
+        initEnv();
+        initEngine();
+
+        reader.setDaemon(true);
+        reader.setName("STD Reader");
+        reader.start();
+    }
+}
--- a/src/me/topchetoeu/jscript/Metadata.java
+++ b/src/me/topchetoeu/jscript/Metadata.java
@@ -1,7 +1,20 @@
 package me.topchetoeu.jscript;

 public class Metadata {
-    public static final String VERSION = "${VERSION}";
-    public static final String AUTHOR = "${AUTHOR}";
-    public static final String NAME = "${NAME}";
+    private static final String VERSION = "${VERSION}";
+    private static final String AUTHOR = "${AUTHOR}";
+    private static final String NAME = "${NAME}";
+
+    public static String version() {
+        if (VERSION.equals("$" + "{VERSION}")) return "1337-devel";
+        else return VERSION;
+    }
+    public static String author() {
+        if (AUTHOR.equals("$" + "{AUTHOR}")) return "anonymous";
+        else return AUTHOR;
+    }
+    public static String name() {
+        if (NAME.equals("$" + "{NAME}")) return "some-product";
+        else return NAME;
+    }
 }
--- a/src/me/topchetoeu/jscript/Reading.java
+++ b/src/me/topchetoeu/jscript/Reading.java
@@ -0,0 +1,36 @@
+package me.topchetoeu.jscript;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
+import me.topchetoeu.jscript.exceptions.UncheckedException;
+
+public class Reading {
+    private static final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+
+    public static synchronized String read() throws IOException {
+        return reader.readLine();
+    }
+
+    public static String streamToString(InputStream in) {
+        try {
+            StringBuilder out = new StringBuilder();
+            BufferedReader br = new BufferedReader(new InputStreamReader(in));
+
+            for(var line = br.readLine(); line != null; line = br.readLine()) {
+                out.append(line).append('\n');
+            }
+
+            br.close();
+            return out.toString();
+        }
+        catch (Throwable e) { throw new UncheckedException(e); }
+    }
+    public static String resourceToString(String name) {
+        var str = Main.class.getResourceAsStream("/me/topchetoeu/jscript/" + name);
+        if (str == null) return null;
+        return streamToString(str);
+    }
+}
--- a/src/me/topchetoeu/jscript/compilation/CompileTarget.java
+++ b/src/me/topchetoeu/jscript/compilation/CompileTarget.java
@@ -1,11 +1,15 @@
 package me.topchetoeu.jscript.compilation;

 import java.util.Map;
+import java.util.TreeSet;
 import java.util.Vector;

+import me.topchetoeu.jscript.Location;
+
 public class CompileTarget {
    public final Vector<Instruction> target = new Vector<>();
-    public final Map<Long, Instruction[]> functions;
+    public final Map<Long, FunctionBody> functions;
+    public final TreeSet<Location> breakpoints;

    public Instruction add(Instruction instr) {
        target.add(instr);
@@ -14,6 +18,12 @@ public class CompileTarget {
    public Instruction set(int i, Instruction instr) {
        return target.set(i, instr);
    }
+    public void setDebug(int i) {
+        breakpoints.add(target.get(i).location);
+    }
+    public void setDebug() {
+        setDebug(target.size() - 1);
+    }
    public Instruction get(int i) {
        return target.get(i);
    }
@@ -21,7 +31,8 @@ public class CompileTarget {

    public Instruction[] array() { return target.toArray(Instruction[]::new); }

-    public CompileTarget(Map<Long, Instruction[]> functions) {
+    public CompileTarget(Map<Long, FunctionBody> functions, TreeSet<Location> breakpoints) {
        this.functions = functions;
+        this.breakpoints = breakpoints;
    }
 }
--- a/src/me/topchetoeu/jscript/compilation/CompoundStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/CompoundStatement.java
@@ -11,6 +11,7 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;

 public class CompoundStatement extends Statement {
    public final Statement[] statements;
+    public Location end;

    @Override
    public void declare(ScopeRecord varsScope) {
@@ -23,20 +24,23 @@ public class CompoundStatement extends Statement {
    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
        for (var stm : statements) {
            if (stm instanceof FunctionStatement) {
-                int start = target.size();
                ((FunctionStatement)stm).compile(target, scope, null, true);
-                target.get(start).setDebug(true);
                target.add(Instruction.discard());
            }
        }

        for (var i = 0; i < statements.length; i++) {
            var stm = statements[i];
-            
+
            if (stm instanceof FunctionStatement) continue;
            if (i != statements.length - 1) stm.compileWithDebug(target, scope, false);
            else stm.compileWithDebug(target, scope, pollute);
        }
+
+        if (end != null) {
+            target.add(Instruction.nop().locate(end));
+            target.setDebug();
+        }
    }

    @Override
@@ -59,6 +63,11 @@ public class CompoundStatement extends Statement {
        else return new CompoundStatement(loc(), res.toArray(Statement[]::new));
    }

+    public CompoundStatement setEnd(Location loc) {
+        this.end = loc;
+        return this;
+    }
+
    public CompoundStatement(Location loc, Statement ...statements) {
        super(loc);
        this.statements = statements;
--- a/src/me/topchetoeu/jscript/compilation/FunctionBody.java
+++ b/src/me/topchetoeu/jscript/compilation/FunctionBody.java
@@ -0,0 +1,17 @@
+package me.topchetoeu.jscript.compilation;
+
+public class FunctionBody {
+    public final Instruction[] instructions;
+    public final String[] captureNames, localNames;
+
+    public FunctionBody(Instruction[] instructions, String[] captureNames, String[] localNames) {
+        this.instructions = instructions;
+        this.captureNames = captureNames;
+        this.localNames = localNames;
+    }
+    public FunctionBody(Instruction[] instructions) {
+        this.instructions = instructions;
+        this.captureNames = new String[0];
+        this.localNames = new String[0];
+    }
+}
--- a/src/me/topchetoeu/jscript/compilation/Instruction.java
+++ b/src/me/topchetoeu/jscript/compilation/Instruction.java
@@ -90,16 +90,11 @@ public class Instruction {
    public final Type type;
    public final Object[] params;
    public Location location;
-    public boolean debugged;

    public Instruction locate(Location loc) {
        this.location = loc;
        return this;
    }
-    public Instruction setDebug(boolean debug) {
-        debugged = debug;
-        return this;
-    }

    @SuppressWarnings("unchecked")
    public <T> T get(int i) {
@@ -152,14 +147,6 @@ public class Instruction {
    public static Instruction debug() {
        return new Instruction(null, Type.NOP, "debug");
    }
-    public static Instruction debugVarNames(String[] names) {
-        var args = new Object[names.length + 1];
-        args[0] = "dbg_vars";
-
-        System.arraycopy(names, 0, args, 1, names.length);
-
-        return new Instruction(null, Type.NOP, args);
-    }

    public static Instruction nop(Object ...params) {
        for (var param : params) {
@@ -264,8 +251,8 @@ public class Instruction {
        return new Instruction(null, Type.TYPEOF, varName);
    }

-    public static Instruction keys() {
-        return new Instruction(null, Type.KEYS);
+    public static Instruction keys(boolean forInFormat) {
+        return new Instruction(null, Type.KEYS, forInFormat);
    }

    public static Instruction defProp() {
--- a/src/me/topchetoeu/jscript/compilation/Statement.java
+++ b/src/me/topchetoeu/jscript/compilation/Statement.java
@@ -14,7 +14,7 @@ public abstract class Statement {
    public void compileWithDebug(CompileTarget target, ScopeRecord scope, boolean pollute) {
        int start = target.size();
        compile(target, scope, pollute);
-        if (target.size() != start) target.get(start).setDebug(true);
+        if (target.size() != start) target.setDebug(start);
    }

    public Location loc() { return _loc; }
--- a/src/me/topchetoeu/jscript/compilation/VariableDeclareStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/VariableDeclareStatement.java
@@ -10,10 +10,12 @@ public class VariableDeclareStatement extends Statement {
    public static class Pair {
        public final String name;
        public final Statement value;
+        public final Location location;

-        public Pair(String name, Statement value) {
+        public Pair(String name, Statement value, Location location) {
            this.name = name;
            this.value = value;
+            this.location = location;
        }
    }

@@ -30,16 +32,20 @@ public class VariableDeclareStatement extends Statement {
        for (var entry : values) {
            if (entry.name == null) continue;
            var key = scope.getKey(entry.name);
-            if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(loc()));
+            int start = target.size();
+
+            if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(entry.location));

            if (entry.value instanceof FunctionStatement) {
                ((FunctionStatement)entry.value).compile(target, scope, entry.name, false);
-                target.add(Instruction.storeVar(key).locate(loc()));
+                target.add(Instruction.storeVar(key).locate(entry.location));
            }
            else if (entry.value != null) {
                entry.value.compile(target, scope, true);
-                target.add(Instruction.storeVar(key).locate(loc()));
+                target.add(Instruction.storeVar(key).locate(entry.location));
            }
+
+            if (target.size() != start) target.setDebug(start);
        }

        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
--- a/src/me/topchetoeu/jscript/compilation/control/ForInStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/control/ForInStatement.java
@@ -12,6 +12,7 @@ public class ForInStatement extends Statement {
    public final boolean isDeclaration;
    public final Statement varValue, object, body;
    public final String label;
+    public final Location varLocation;

    @Override
    public void declare(ScopeRecord globScope) {
@@ -22,6 +23,8 @@ public class ForInStatement extends Statement {
    @Override
    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
        var key = scope.getKey(varName);
+
+        int first = target.size();
        if (key instanceof String) target.add(Instruction.makeVar((String)key));

        if (varValue != null) {
@@ -29,45 +32,37 @@ public class ForInStatement extends Statement {
            target.add(Instruction.storeVar(scope.getKey(varName)));
        }

-        object.compile(target, scope, true);
-        target.add(Instruction.keys());
-        
+        object.compileWithDebug(target, scope, true);
+        target.add(Instruction.keys(true));
+
        int start = target.size();
        target.add(Instruction.dup());
-        target.add(Instruction.loadMember("length"));
-        target.add(Instruction.loadValue(0));
-        target.add(Instruction.operation(Operation.LESS_EQUALS));
+        target.add(Instruction.loadValue(null));
+        target.add(Instruction.operation(Operation.EQUALS));
        int mid = target.size();
        target.add(Instruction.nop());

-        target.add(Instruction.dup());
-        target.add(Instruction.dup());
-        target.add(Instruction.loadMember("length"));
-        target.add(Instruction.loadValue(1));
-        target.add(Instruction.operation(Operation.SUBTRACT));
-        target.add(Instruction.dup(1, 2));
-        target.add(Instruction.loadValue("length"));
-        target.add(Instruction.dup(1, 2));
-        target.add(Instruction.storeMember());
-        target.add(Instruction.loadMember());
+        target.add(Instruction.loadMember("value").locate(varLocation));
+        target.setDebug();
        target.add(Instruction.storeVar(key));

-        for (var i = start; i < target.size(); i++) target.get(i).locate(loc());
-
        body.compileWithDebug(target, scope, false);

        int end = target.size();

        WhileStatement.replaceBreaks(target, label, mid + 1, end, start, end + 1);

-        target.add(Instruction.jmp(start - end).locate(loc()));
-        target.add(Instruction.discard().locate(loc()));
-        target.set(mid, Instruction.jmpIf(end - mid + 1).locate(loc()));
-        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
+        target.add(Instruction.jmp(start - end));
+        target.add(Instruction.discard());
+        target.set(mid, Instruction.jmpIf(end - mid + 1));
+        if (pollute) target.add(Instruction.loadValue(null));
+        target.get(first).locate(loc());
+        target.setDebug(first);
    }

-    public ForInStatement(Location loc, String label, boolean isDecl, String varName, Statement varValue, Statement object, Statement body) {
+    public ForInStatement(Location loc, Location varLocation, String label, boolean isDecl, String varName, Statement varValue, Statement object, Statement body) {
        super(loc);
+        this.varLocation = varLocation;
        this.label = label;
        this.isDeclaration = isDecl;
        this.varName = varName;
--- a/src/me/topchetoeu/jscript/compilation/control/SwitchStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/control/SwitchStatement.java
@@ -33,8 +33,8 @@ public class SwitchStatement extends Statement {

    @Override
    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
-        var caseMap = new HashMap<Integer, Integer>();
-        var stmIndexMap = new HashMap<Integer, Integer>();
+        var caseToStatement = new HashMap<Integer, Integer>();
+        var statementToIndex = new HashMap<Integer, Integer>();

        value.compile(target, scope, true);

@@ -42,8 +42,8 @@ public class SwitchStatement extends Statement {
            target.add(Instruction.dup().locate(loc()));
            ccase.value.compile(target, scope, true);
            target.add(Instruction.operation(Operation.EQUALS).locate(loc()));
-            caseMap.put(target.size(), ccase.statementI);
-            target.add(Instruction.nop());
+            caseToStatement.put(target.size(), ccase.statementI);
+            target.add(Instruction.nop().locate(ccase.value.loc()));
        }

        int start = target.size();
@@ -51,27 +51,31 @@ public class SwitchStatement extends Statement {
        target.add(Instruction.nop());

        for (var stm : body) {
-            stmIndexMap.put(stmIndexMap.size(), target.size());
+            statementToIndex.put(statementToIndex.size(), target.size());
            stm.compileWithDebug(target, scope, false);
        }

-        if (defaultI < 0 || defaultI >= body.length) target.set(start, Instruction.jmp(target.size() - start).locate(loc()));
-        else target.set(start, Instruction.jmp(stmIndexMap.get(defaultI) - start)).locate(loc());
+        int end = target.size();
+        target.add(Instruction.discard().locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null));

-        for (int i = start; i < target.size(); i++) {
+        if (defaultI < 0 || defaultI >= body.length) target.set(start, Instruction.jmp(end - start).locate(loc()));
+        else target.set(start, Instruction.jmp(statementToIndex.get(defaultI) - start)).locate(loc());
+
+        for (int i = start; i < end; i++) {
            var instr = target.get(i);
            if (instr.type == Type.NOP && instr.is(0, "break") && instr.get(1) == null) {
-                target.set(i, Instruction.jmp(target.size() - i).locate(instr.location));
+                target.set(i, Instruction.jmp(end - i).locate(instr.location));
            }
        }
-        for (var el : caseMap.entrySet()) {
+        for (var el : caseToStatement.entrySet()) {
            var loc = target.get(el.getKey()).location;
-            var i = stmIndexMap.get(el.getValue());
-            if (i == null) i = target.size();
-            target.set(el.getKey(), Instruction.jmpIf(i - el.getKey()).locate(loc).setDebug(true));
+            var i = statementToIndex.get(el.getValue());
+            if (i == null) i = end;
+            target.set(el.getKey(), Instruction.jmpIf(i - el.getKey()).locate(loc));
+            target.setDebug(el.getKey());
        }

-        target.add(Instruction.discard().locate(loc()));
    }

    public SwitchStatement(Location loc, Statement value, int defaultI, SwitchCase[] cases, Statement[] body) {
--- a/src/me/topchetoeu/jscript/compilation/values/CallStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/CallStatement.java
@@ -16,13 +16,14 @@ public class CallStatement extends Statement {
            ((IndexStatement)func).compile(target, scope, true, true);
        }
        else {
-               target.add(Instruction.loadValue(null).locate(loc()));
+            target.add(Instruction.loadValue(null).locate(loc()));
            func.compile(target, scope, true);
        }

        for (var arg : args) arg.compile(target, scope, true);

-        target.add(Instruction.call(args.length).locate(loc()).setDebug(true));
+        target.add(Instruction.call(args.length).locate(loc()));
+        target.setDebug();
        if (!pollute) target.add(Instruction.discard().locate(loc()));
    }

--- a/src/me/topchetoeu/jscript/compilation/values/ChangeStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/ChangeStatement.java
@@ -15,8 +15,12 @@ public class ChangeStatement extends Statement {

    @Override
    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
-        value.toAssign(new ConstantStatement(loc(), -addAmount), Operation.SUBTRACT).compile(target, scope, postfix);
+        value.toAssign(new ConstantStatement(loc(), -addAmount), Operation.SUBTRACT).compile(target, scope, true);
        if (!pollute) target.add(Instruction.discard().locate(loc()));
+        else if (postfix) {
+            target.add(Instruction.loadValue(addAmount));
+            target.add(Instruction.operation(Operation.SUBTRACT));
+        }
    }

    public ChangeStatement(Location loc, AssignableStatement value, double addAmount, boolean postfix) {
--- a/src/me/topchetoeu/jscript/compilation/values/CommaStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/CommaStatement.java
@@ -0,0 +1,38 @@
+package me.topchetoeu.jscript.compilation.values;
+
+import java.util.Vector;
+
+import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.CompileTarget;
+import me.topchetoeu.jscript.compilation.Statement;
+import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+
+public class CommaStatement extends Statement {
+    public final Statement[] values;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        for (var i = 0; i < values.length; i++) {
+            values[i].compileWithDebug(target, scope, i == values.length - 1 && pollute);
+        }
+    }
+    
+    @Override
+    public Statement optimize() {
+        var res = new Vector<Statement>(values.length);
+
+        for (var i = 0; i < values.length; i++) {
+            var stm = values[i].optimize();
+            if (i < values.length - 1 && stm.pure()) continue;
+            res.add(stm);
+        }
+
+        if (res.size() == 1) return res.get(0);
+        else return new CommaStatement(loc(), res.toArray(Statement[]::new));
+    }
+
+    public CommaStatement(Location loc, Statement ...args) {
+        super(loc);
+        this.values = args;
+    }
+}
--- a/src/me/topchetoeu/jscript/compilation/values/FunctionStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/FunctionStatement.java
@@ -5,6 +5,7 @@ import java.util.Random;
 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.compilation.CompileTarget;
 import me.topchetoeu.jscript.compilation.CompoundStatement;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
 import me.topchetoeu.jscript.compilation.Instruction.Type;
@@ -51,7 +52,7 @@ public class FunctionStatement extends Statement {
        var subscope = scope.child();

        int start = target.size();
-        var funcTarget = new CompileTarget(target.functions);
+        var funcTarget = new CompileTarget(target.functions, target.breakpoints);

        subscope.define("this");
        var argsVar = subscope.define("arguments");
@@ -69,7 +70,6 @@ public class FunctionStatement extends Statement {
        }

        body.declare(subscope);
-        funcTarget.add(Instruction.debugVarNames(subscope.locals()));
        body.compile(funcTarget, subscope, false);
        funcTarget.add(Instruction.ret().locate(loc()));
        checkBreakAndCont(funcTarget, start);
@@ -77,7 +77,7 @@ public class FunctionStatement extends Statement {
        var id = rand.nextLong();

        target.add(Instruction.loadFunc(id, subscope.localsCount(), args.length, subscope.getCaptures()).locate(loc()));
-        target.functions.put(id, funcTarget.array());
+        target.functions.put(id, new FunctionBody(funcTarget.array(), subscope.captures(), subscope.locals()));

        if (name == null) name = this.name;

--- a/src/me/topchetoeu/jscript/compilation/values/IndexAssignStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/IndexAssignStatement.java
@@ -24,14 +24,16 @@ public class IndexAssignStatement extends Statement {
            value.compile(target, scope, true);
            target.add(Instruction.operation(operation).locate(loc()));

-            target.add(Instruction.storeMember(pollute).locate(loc()).setDebug(true));
+            target.add(Instruction.storeMember(pollute).locate(loc()));
+            target.setDebug();
        }
        else {
            object.compile(target, scope, true);
            index.compile(target, scope, true);
            value.compile(target, scope, true);

-            target.add(Instruction.storeMember(pollute).locate(loc()).setDebug(true));
+            target.add(Instruction.storeMember(pollute).locate(loc()));
+            target.setDebug();
        }
    }

--- a/src/me/topchetoeu/jscript/compilation/values/IndexStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/IndexStatement.java
@@ -20,17 +20,17 @@ public class IndexStatement extends AssignableStatement {
        return new IndexAssignStatement(loc(), object, index, val, operation);
    }
    public void compile(CompileTarget target, ScopeRecord scope, boolean dupObj, boolean pollute) {
-        int start = 0;
        object.compile(target, scope, true);
        if (dupObj) target.add(Instruction.dup().locate(loc()));
        if (index instanceof ConstantStatement) {
            target.add(Instruction.loadMember(((ConstantStatement)index).value).locate(loc()));
+            target.setDebug();
            return;
        }

        index.compile(target, scope, true);
        target.add(Instruction.loadMember().locate(loc()));
-        target.get(start).setDebug(true);
+        target.setDebug();
        if (!pollute) target.add(Instruction.discard().locate(loc()));
    }
    @Override
--- a/src/me/topchetoeu/jscript/compilation/values/LazyAndStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/LazyAndStatement.java
@@ -29,7 +29,7 @@ public class LazyAndStatement extends Statement {
        if (pollute) target.add(Instruction.dup().locate(loc()));
        int start = target.size();
        target.add(Instruction.nop());
-        target.add(Instruction.discard().locate(loc()));
+        if (pollute) target.add(Instruction.discard().locate(loc()));
        second.compile(target, scope, pollute);
        target.set(start, Instruction.jmpIfNot(target.size() - start).locate(loc()));
    }
--- a/src/me/topchetoeu/jscript/compilation/values/LazyOrStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/LazyOrStatement.java
@@ -29,7 +29,7 @@ public class LazyOrStatement extends Statement {
        if (pollute) target.add(Instruction.dup().locate(loc()));
        int start = target.size();
        target.add(Instruction.nop());
-        target.add(Instruction.discard().locate(loc()));
+        if (pollute) target.add(Instruction.discard().locate(loc()));
        second.compile(target, scope, pollute);
        target.set(start, Instruction.jmpIf(target.size() - start).locate(loc()));
    }
--- a/src/me/topchetoeu/jscript/compilation/values/NewStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/NewStatement.java
@@ -16,7 +16,8 @@ public class NewStatement extends Statement {

        for (var arg : args) arg.compile(target, scope, true);

-        target.add(Instruction.callNew(args.length).locate(loc()).setDebug(true));
+        target.add(Instruction.callNew(args.length).locate(loc()));
+        target.setDebug();
    }

    public NewStatement(Location loc, Statement func, Statement ...args) {
--- a/src/me/topchetoeu/jscript/compilation/values/OperationStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/OperationStatement.java
@@ -49,13 +49,8 @@ public class OperationStatement extends Statement {
                vals[i] = ((ConstantStatement)args[i]).value;
            }

-            try {
-                return new ConstantStatement(loc(), Values.operation(null, operation, vals));
-            }
-            catch (EngineException e) {
-                return new ThrowStatement(loc(), new ConstantStatement(loc(), e.value));
-            }
-            catch (InterruptedException e) { return null; }
+            try { return new ConstantStatement(loc(), Values.operation(null, operation, vals)); }
+            catch (EngineException e) { return new ThrowStatement(loc(), new ConstantStatement(loc(), e.value)); }
        }

        return new OperationStatement(loc(), operation, args);
--- a/src/me/topchetoeu/jscript/compilation/values/VariableAssignStatement.java
+++ b/src/me/topchetoeu/jscript/compilation/values/VariableAssignStatement.java
@@ -20,15 +20,13 @@ public class VariableAssignStatement extends Statement {
            if (value instanceof FunctionStatement) ((FunctionStatement)value).compile(target, scope, name, false);
            else value.compile(target, scope, true);
            target.add(Instruction.operation(operation).locate(loc()));
-            target.add(Instruction.storeVar(i, false).locate(loc()));
+            target.add(Instruction.storeVar(i, pollute).locate(loc()));
        }
        else {
            if (value instanceof FunctionStatement) ((FunctionStatement)value).compile(target, scope, name, false);
            else value.compile(target, scope, true);
-            target.add(Instruction.storeVar(i, false).locate(loc()));
+            target.add(Instruction.storeVar(i, pollute).locate(loc()));
        }
-
-        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
    }

    public VariableAssignStatement(Location loc, String name, Statement val, Operation operation) {
--- a/src/me/topchetoeu/jscript/engine/Context.java
+++ b/src/me/topchetoeu/jscript/engine/Context.java
@@ -1,27 +1,111 @@
 package me.topchetoeu.jscript.engine;

+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Stack;
+import java.util.TreeSet;
+
+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.parsing.Parsing;

 public class Context {
-    public final Environment env;
-    public final Message message;
+    private final Stack<Environment> env = new Stack<>();
+    private final ArrayList<CodeFrame> frames = new ArrayList<>();
+    public final Engine engine;

-    public FunctionValue compile(String filename, String raw) throws InterruptedException {
-        var res = Values.toString(this, env.compile.call(this, null, raw, filename));
-        return Parsing.compile(message.engine.functions, env, filename, res);
+    public Environment environment() {
+        return env.empty() ? null : env.peek();
    }

-    public Context setEnv(Environment env) {
-        return new Context(env, message);
+    public Context pushEnv(Environment env) {
+        this.env.push(env);
+        return this;
    }
-    public Context setMsg(Message msg) {
-        return new Context(env, msg);
+    public void popEnv() {
+        if (!env.empty()) this.env.pop();
    }

-    public Context(Environment env, Message msg) {
-        this.env = env;
-        this.message = msg;
+    public FunctionValue compile(Filename filename, String raw) {
+        var env = environment();
+        var transpiled = env.compile.call(this, null, raw, filename.toString(), env);
+        String source = null;
+        FunctionValue runner = null;
+
+        if (transpiled instanceof ObjectValue) {
+            source = Values.toString(this, Values.getMember(this, transpiled, "source"));
+            var _runner = Values.getMember(this, transpiled, "runner");
+            if (_runner instanceof FunctionValue) runner = (FunctionValue)_runner;
+        }
+        else source = Values.toString(this, transpiled);
+
+        var breakpoints = new TreeSet<Location>();
+        FunctionValue res = Parsing.compile(Engine.functions, breakpoints, env, filename, source);
+        engine.onSource(filename, source, breakpoints);
+
+        if (runner != null) res = (FunctionValue)runner.call(this, null, res);
+
+        return res;
+    }
+
+
+    public void pushFrame(CodeFrame frame) {
+        frames.add(frame);
+        if (frames.size() > engine.maxStackFrames) throw EngineException.ofRange("Stack overflow!");
+        pushEnv(frame.function.environment);
+    }
+    public boolean popFrame(CodeFrame frame) {
+        if (frames.size() == 0) return false;
+        if (frames.get(frames.size() - 1) != frame) return false;
+        frames.remove(frames.size() - 1);
+        popEnv();
+        engine.onFramePop(this, frame);
+        return true;
+    }
+    public CodeFrame peekFrame() {
+        if (frames.size() == 0) return null;
+        return frames.get(frames.size() - 1);
+    }
+
+    public List<CodeFrame> frames() {
+        return Collections.unmodifiableList(frames);
+    }
+    public List<String> stackTrace() {
+        var res = new ArrayList<String>();
+
+        for (var i = frames.size() - 1; i >= 0; i--) {
+            var el = frames.get(i);
+            var name = el.function.name;
+            Location loc = null;
+
+            for (var j = el.codePtr; j >= 0 && loc == null; j--) loc = el.function.body[j].location;
+            if (loc == null) loc = el.function.loc();
+
+            var trace = "";
+
+            if (loc != null) trace += "at " + loc.toString() + " ";
+            if (name != null && !name.equals("")) trace += "in " + name + " ";
+
+            trace = trace.trim();
+
+            if (!trace.equals("")) res.add(trace);
+        }
+
+        return res;
+    }
+
+    public Context(Engine engine) {
+        this.engine = engine;
+    }
+    public Context(Engine engine, Environment env) {
+        this(engine);
+        this.pushEnv(env);
+        
    }
 }
--- a/src/me/topchetoeu/jscript/engine/Data.java
+++ b/src/me/topchetoeu/jscript/engine/Data.java
@@ -1,43 +1,44 @@
 package me.topchetoeu.jscript.engine;

 import java.util.HashMap;
-import java.util.Iterator;
-import java.util.Map.Entry;
+import java.util.Map;

@SuppressWarnings("unchecked")
-public class Data implements Iterable<Entry<DataKey<?>, ?>> {
+public class Data {
    private HashMap<DataKey<Object>, Object> data = new HashMap<>();

    public Data copy() {
        return new Data().addAll(this);
    }

-    public Data addAll(Iterable<Entry<DataKey<?>, ?>> data) {
-        for (var el : data) {
-            add((DataKey<Object>)el.getKey(), (Object)el.getValue());
+    public Data addAll(Map<DataKey<?>, ?> data) {
+        for (var el : data.entrySet()) {
+            get((DataKey<Object>)el.getKey(), (Object)el.getValue());
+        }
+        return this;
+    }
+    public Data addAll(Data data) {
+        for (var el : data.data.entrySet()) {
+            get((DataKey<Object>)el.getKey(), (Object)el.getValue());
        }
        return this;
    }

+    public <T> T remove(DataKey<T> key) {
+        return (T)data.remove(key);
+    }
    public <T> Data set(DataKey<T> key, T val) {
-        if (val == null) data.remove(key);
-        else data.put((DataKey<Object>)key, (Object)val);
+        data.put((DataKey<Object>)key, (Object)val);
        return this;
    }
-    public <T> T add(DataKey<T> key, T val) {
-        if (data.containsKey(key)) return (T)data.get(key);
-        else {
-            if (val == null) data.remove(key);
-            else data.put((DataKey<Object>)key, (Object)val);
-            return val;
-        }
+    public <T> T get(DataKey<T> key, T val) {
+        if (data.containsKey(key)) return (T)data.get((DataKey<Object>)key);
+        set(key, val);
+        return val;
    }
    public <T> T get(DataKey<T> key) {
-        return get(key, null);
-    }
-    public <T> T get(DataKey<T> key, T defaultVal) {
-        if (!has(key)) return defaultVal;
-        else return (T)data.get(key);
+        if (data.containsKey(key)) return (T)data.get((DataKey<Object>)key);
+        return null;
    }
    public boolean has(DataKey<?> key) { return data.containsKey(key); }

@@ -52,9 +53,4 @@ public class Data implements Iterable<Entry<DataKey<?>, ?>> {
    public int increase(DataKey<Integer> key) {
        return increase(key, 1, 0);
    }
-
-    @Override
-    public Iterator<Entry<DataKey<?>, ?>> iterator() {
-        return (Iterator<Entry<DataKey<?>, ?>>)data.entrySet();
-    }
 }
--- a/src/me/topchetoeu/jscript/engine/Engine.java
+++ b/src/me/topchetoeu/jscript/engine/Engine.java
@@ -1,87 +1,108 @@
 package me.topchetoeu.jscript.engine;

 import java.util.HashMap;
-import java.util.concurrent.LinkedBlockingDeque;
+import java.util.TreeSet;
+import java.util.concurrent.PriorityBlockingQueue;

+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.compilation.Instruction;
+import me.topchetoeu.jscript.engine.debug.DebugController;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
 import me.topchetoeu.jscript.events.Awaitable;
 import me.topchetoeu.jscript.events.DataNotifier;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.exceptions.InterruptException;

-public class Engine {
+public class Engine implements DebugController {
    private class UncompiledFunction extends FunctionValue {
-        public final String filename;
+        public final Filename filename;
        public final String raw;
-        public final Environment env;
+        private FunctionValue compiled = null;

        @Override
-        public Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
-            ctx = ctx.setEnv(env);
-            return ctx.compile(filename, raw).call(ctx, thisArg, args);
+        public Object call(Context ctx, Object thisArg, Object ...args) {
+            if (compiled == null) compiled = ctx.compile(filename, raw);
+            return compiled.call(ctx, thisArg, args);
        }

-        public UncompiledFunction(Environment env, String filename, String raw) {
-            super(filename, 0);
+        public UncompiledFunction(Filename filename, String raw) {
+            super(filename + "", 0);
            this.filename = filename;
            this.raw = raw;
-            this.env = env; 
        }
    }

-    private static class Task {
+    private static class Task implements Comparable<Task> {
        public final FunctionValue func;
        public final Object thisArg;
        public final Object[] args;
        public final DataNotifier<Object> notifier = new DataNotifier<>();
-        public final Message msg;
+        public final Context ctx;
+        public final boolean micro;

-        public Task(Message ctx, FunctionValue func, Object thisArg, Object[] args) {
-            this.msg = ctx;
+        public Task(Context ctx, FunctionValue func, Object thisArg, Object[] args, boolean micro) {
+            this.ctx = ctx;
            this.func = func;
            this.thisArg = thisArg;
            this.args = args;
+            this.micro = micro;
+        }
+
+        @Override
+        public int compareTo(Task other) {
+            return Integer.compare(this.micro ? 0 : 1, other.micro ? 0 : 1);
        }
    }

    private static int nextId = 0;
-
-    private Thread thread;
-    private LinkedBlockingDeque<Task> macroTasks = new LinkedBlockingDeque<>();
-    private LinkedBlockingDeque<Task> microTasks = new LinkedBlockingDeque<>();
+    public static final HashMap<Long, FunctionBody> functions = new HashMap<>();

    public final int id = ++nextId;
-    public final HashMap<Long, Instruction[]> functions = new HashMap<>();
+    public final boolean debugging;
+    public int maxStackFrames = 10000;

-    private void runTask(Task task) throws InterruptedException {
+    private final HashMap<Filename, String> sources = new HashMap<>();
+    private final HashMap<Filename, TreeSet<Location>> bpts = new HashMap<>();
+
+    private DebugController debugger;
+    private Thread thread;
+    private PriorityBlockingQueue<Task> tasks = new PriorityBlockingQueue<>();
+
+    public boolean attachDebugger(DebugController debugger) {
+        if (!debugging || this.debugger != null) return false;
+
+        for (var source : sources.entrySet()) {
+            debugger.onSource(source.getKey(), source.getValue(), bpts.get(source.getKey()));
+        }
+
+        this.debugger = debugger;
+        return true;
+    }
+    public boolean detachDebugger() {
+        if (!debugging || this.debugger == null) return false;
+        this.debugger = null;
+        return true;
+    }
+
+    private void runTask(Task task) {
        try {
-            task.notifier.next(task.func.call(task.msg.context(null), task.thisArg, task.args));
-        }
-        catch (InterruptedException e) {
-            task.notifier.error(new RuntimeException(e));
-            throw e;
-        }
-        catch (EngineException e) {
-            task.notifier.error(e);
+            task.notifier.next(task.func.call(task.ctx, task.thisArg, task.args));
        }
        catch (RuntimeException e) {
+            if (e instanceof InterruptException) throw e;
            task.notifier.error(e);
-            e.printStackTrace();
        }
    }
-    private void run() {
-        while (true) {
+    public void run(boolean untilEmpty) {
+        while (!untilEmpty || !tasks.isEmpty()) {
            try {
-                runTask(macroTasks.take());
-
-                while (!microTasks.isEmpty()) {
-                    runTask(microTasks.take());
-                }
+                runTask(tasks.take());
            }
-            catch (InterruptedException e) {
-                for (var msg : macroTasks) {
-                    msg.notifier.error(new RuntimeException(e));
-                }
+            catch (InterruptedException | InterruptException e) {
+                for (var msg : tasks) msg.notifier.error(new InterruptException(e));
                break;
            }
        }
@@ -89,7 +110,7 @@ public class Engine {

    public Thread start() {
        if (this.thread == null) {
-            this.thread = new Thread(this::run, "JavaScript Runner #" + id);
+            this.thread = new Thread(() -> run(false), "JavaScript Runner #" + id);
            this.thread.start();
        }
        return this.thread;
@@ -105,17 +126,30 @@ public class Engine {
        return this.thread != null;
    }

-    public Awaitable<Object> pushMsg(boolean micro, Message ctx, FunctionValue func, Object thisArg, Object ...args) {
-        var msg = new Task(ctx, func, thisArg, args);
-        if (micro) microTasks.addLast(msg);
-        else macroTasks.addLast(msg);
+    public Awaitable<Object> pushMsg(boolean micro, Context ctx, FunctionValue func, Object thisArg, Object ...args) {
+        var msg = new Task(ctx == null ? new Context(this) : ctx, func, thisArg, args, micro);
+        tasks.add(msg);
        return msg.notifier;
    }
-    public Awaitable<Object> pushMsg(boolean micro, Context ctx, String filename, String raw, Object thisArg, Object ...args) {
-        return pushMsg(micro, ctx.message, new UncompiledFunction(ctx.env, filename, raw), thisArg, args);
+    public Awaitable<Object> pushMsg(boolean micro, Context ctx, Filename filename, String raw, Object thisArg, Object ...args) {
+        return pushMsg(micro, ctx, new UncompiledFunction(filename, raw), thisArg, args);
    }

-    // public Engine() {
-    //     this.typeRegister = new NativeTypeRegister();
-    // }
+    @Override public void onFramePop(Context ctx, CodeFrame frame) {
+        if (debugging && debugger != null) debugger.onFramePop(ctx, frame);
+    }
+    @Override public boolean onInstruction(Context ctx, CodeFrame frame, Instruction instruction, Object returnVal, EngineException error, boolean caught) {
+        if (debugging && debugger != null) return debugger.onInstruction(ctx, frame, instruction, returnVal, error, caught);
+        else return false;
+    }
+    @Override public void onSource(Filename filename, String source, TreeSet<Location> breakpoints) {
+        if (!debugging) return;
+        if (debugger != null) debugger.onSource(filename, source, breakpoints);
+        sources.put(filename, source);
+        bpts.put(filename, breakpoints);
+    }
+
+    public Engine(boolean debugging) {
+        this.debugging = debugging;
+    }
 }
--- a/src/me/topchetoeu/jscript/engine/Environment.java
+++ b/src/me/topchetoeu/jscript/engine/Environment.java
@@ -8,23 +8,32 @@ import me.topchetoeu.jscript.engine.values.NativeFunction;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.engine.values.Symbol;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.filesystem.RootFilesystem;
 import me.topchetoeu.jscript.interop.Native;
 import me.topchetoeu.jscript.interop.NativeGetter;
 import me.topchetoeu.jscript.interop.NativeSetter;
 import me.topchetoeu.jscript.interop.NativeWrapperProvider;
+import me.topchetoeu.jscript.permissions.Permission;
+import me.topchetoeu.jscript.permissions.PermissionsProvider;

-public class Environment {
+public class Environment implements PermissionsProvider {
    private HashMap<String, ObjectValue> prototypes = new HashMap<>();

    public final Data data = new Data();
-    public final HashMap<String, Symbol> symbols = new HashMap<>();
+    public static final HashMap<String, Symbol> symbols = new HashMap<>();

    public GlobalScope global;
-    public WrappersProvider wrappersProvider;
+    public WrappersProvider wrappers;
+    public PermissionsProvider permissions = null;
+    public final RootFilesystem filesystem = new RootFilesystem(this);
+
+    private static int nextId = 0;
+
+    @Native public int id = ++nextId;

    @Native public FunctionValue compile;
    @Native public FunctionValue regexConstructor = new NativeFunction("RegExp", (ctx, thisArg, args) -> {
-        throw EngineException.ofError("Regular expressions not supported.").setContext(ctx);
+        throw EngineException.ofError("Regular expressions not supported.").setCtx(ctx.environment(), ctx.engine);
    });

    public Environment addData(Data data) {
@@ -40,8 +49,7 @@ public class Environment {
    }

    @Native public Symbol symbol(String name) {
-        if (symbols.containsKey(name))
-            return symbols.get(name);
+        if (symbols.containsKey(name)) return symbols.get(name);
        else {
            var res = new Symbol(name);
            symbols.put(name, res);
@@ -57,7 +65,8 @@ public class Environment {
    }

    @Native public Environment fork() {
-        var res = new Environment(compile, wrappersProvider, global);
+        var res = new Environment(compile, null, global);
+        res.wrappers = wrappers.fork(res);
        res.regexConstructor = regexConstructor;
        res.prototypes = new HashMap<>(prototypes);
        return res;
@@ -68,8 +77,15 @@ public class Environment {
        return res;
    }

-    public Context context(Message msg) {
-        return new Context(this, msg);
+    @Override public boolean hasPermission(Permission perm, char delim) {
+        return permissions == null || permissions.hasPermission(perm, delim);
+    }
+    @Override public boolean hasPermission(Permission perm) {
+        return permissions == null || permissions.hasPermission(perm);
+    }
+
+    public Context context(Engine engine) {
+        return new Context(engine).pushEnv(this);
    }

    public Environment(FunctionValue compile, WrappersProvider nativeConverter, GlobalScope global) {
@@ -77,7 +93,7 @@ public class Environment {
        if (nativeConverter == null) nativeConverter = new NativeWrapperProvider(this);
        if (global == null) global = new GlobalScope();

-        this.wrappersProvider = nativeConverter;
+        this.wrappers = nativeConverter;
        this.compile = compile;
        this.global = global;
    }
--- a/src/me/topchetoeu/jscript/engine/Message.java
+++ b/src/me/topchetoeu/jscript/engine/Message.java
@@ -1,63 +0,0 @@
-package me.topchetoeu.jscript.engine;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
-import me.topchetoeu.jscript.engine.frame.CodeFrame;
-import me.topchetoeu.jscript.exceptions.EngineException;
-
-public class Message {
-    public final Engine engine;
-
-    private final ArrayList<CodeFrame> frames = new ArrayList<>();
-    public int maxStackFrames = 1000;
-
-    public final Data data = new Data();
-
-    public List<CodeFrame> frames() { return Collections.unmodifiableList(frames); }
-
-    public Message addData(Data data) {
-        this.data.addAll(data);
-        return this;
-    }
-
-    public Message pushFrame(Context ctx, CodeFrame frame) throws InterruptedException {
-        this.frames.add(frame);
-        if (this.frames.size() > maxStackFrames) throw EngineException.ofRange("Stack overflow!");
-        return this;
-    }
-    public boolean popFrame(CodeFrame frame) {
-        if (this.frames.size() == 0) return false;
-        if (this.frames.get(this.frames.size() - 1) != frame) return false;
-        this.frames.remove(this.frames.size() - 1);
-        return true;
-    }
-
-    public List<String> stackTrace() {
-        var res = new ArrayList<String>();
-
-        for (var el : frames) {
-            var name = el.function.name;
-            var loc = el.function.loc();
-            var trace = "";
-
-            if (loc != null) trace += "at " + loc.toString() + " ";
-            if (name != null && !name.equals("")) trace += "in " + name + " ";
-
-            trace = trace.trim();
-
-            if (!res.equals("")) res.add(trace);
-        }
-
-        return res;
-    }
-
-    public Context context(Environment env) {
-        return new Context(env, this);
-    }
-
-    public Message(Engine engine) {
-        this.engine = engine;
-    }
-}
--- a/src/me/topchetoeu/jscript/engine/WrappersProvider.java
+++ b/src/me/topchetoeu/jscript/engine/WrappersProvider.java
@@ -5,5 +5,8 @@ import me.topchetoeu.jscript.engine.values.ObjectValue;

 public interface WrappersProvider {
    public ObjectValue getProto(Class<?> obj);
+    public ObjectValue getNamespace(Class<?> obj);
    public FunctionValue getConstr(Class<?> obj);
+
+    public WrappersProvider fork(Environment env);
 }
--- a/src/me/topchetoeu/jscript/engine/debug/DebugController.java
+++ b/src/me/topchetoeu/jscript/engine/debug/DebugController.java
@@ -0,0 +1,40 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.util.TreeSet;
+
+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.Instruction;
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.exceptions.EngineException;
+
+public interface DebugController {
+    /**
+     * Called when a script has been loaded
+     * @param breakpoints 
+     */
+    void onSource(Filename filename, String source, TreeSet<Location> breakpoints);
+
+    /**
+     * Called immediatly before an instruction is executed, as well as after an instruction, if it has threw or returned.
+     * This function might pause in order to await debugging commands.
+     * @param ctx The context of execution
+     * @param frame The frame in which execution is occuring
+     * @param instruction The instruction which was or will be executed
+     * @param loc The most recent location the code frame has been at
+     * @param returnVal The return value of the instruction, Runners.NO_RETURN if none
+     * @param error The error that the instruction threw, null if none
+     * @param caught Whether or not the error has been caught
+     * @return Whether or not the frame should restart
+     */
+    boolean onInstruction(Context ctx, CodeFrame frame, Instruction instruction, Object returnVal, EngineException error, boolean caught);
+
+    /**
+     * Called immediatly after a frame has been popped out of the frame stack.
+     * This function might pause in order to await debugging commands.
+     * @param ctx The context of execution
+     * @param frame The code frame which was popped out
+     */
+    void onFramePop(Context ctx, CodeFrame frame);
+}
--- a/src/me/topchetoeu/jscript/engine/debug/DebugHandler.java
+++ b/src/me/topchetoeu/jscript/engine/debug/DebugHandler.java
@@ -0,0 +1,35 @@
+package me.topchetoeu.jscript.engine.debug;
+
+public interface DebugHandler {
+    void enable(V8Message msg);
+    void disable(V8Message msg);
+
+    void setBreakpoint(V8Message msg);
+    void setBreakpointByUrl(V8Message msg);
+    void removeBreakpoint(V8Message msg);
+    void continueToLocation(V8Message msg);
+
+    void getScriptSource(V8Message msg);
+    void getPossibleBreakpoints(V8Message msg);
+
+    void resume(V8Message msg);
+    void pause(V8Message msg);
+
+    void stepInto(V8Message msg);
+    void stepOut(V8Message msg);
+    void stepOver(V8Message msg);
+
+    void setPauseOnExceptions(V8Message msg);
+
+    void evaluateOnCallFrame(V8Message msg);
+
+    void getProperties(V8Message msg);
+    void releaseObjectGroup(V8Message msg);
+    void releaseObject(V8Message msg);
+    /**
+     * This method might not execute the actual code for well-known requests
+     */
+    void callFunctionOn(V8Message msg);
+
+    void runtimeEnable(V8Message msg);
+}
--- a/src/me/topchetoeu/jscript/engine/debug/DebugServer.java
+++ b/src/me/topchetoeu/jscript/engine/debug/DebugServer.java
@@ -0,0 +1,246 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.security.MessageDigest;
+import java.util.Base64;
+import java.util.HashMap;
+
+import me.topchetoeu.jscript.Metadata;
+import me.topchetoeu.jscript.engine.debug.WebSocketMessage.Type;
+import me.topchetoeu.jscript.events.Notifier;
+import me.topchetoeu.jscript.exceptions.SyntaxException;
+import me.topchetoeu.jscript.exceptions.UncheckedException;
+import me.topchetoeu.jscript.exceptions.UncheckedIOException;
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONList;
+import me.topchetoeu.jscript.json.JSONMap;
+
+public class DebugServer {
+    public static String browserDisplayName = Metadata.name() + "/" + Metadata.version();
+
+    public final HashMap<String, DebuggerProvider> targets = new HashMap<>();
+
+    private final byte[] favicon, index, protocol;
+    private final Notifier connNotifier = new Notifier();
+
+    private static void send(HttpRequest req, String val) throws IOException {
+        req.writeResponse(200, "OK", "application/json", val.getBytes());
+    }
+
+    // SILENCE JAVA
+    private MessageDigest getDigestInstance() {
+        try {
+            return MessageDigest.getInstance("sha1");
+        }
+        catch (Throwable e) { throw new UncheckedException(e); }
+
+    }
+
+    private static Thread runAsync(Runnable func, String name) {
+        var res = new Thread(func);
+        res.setName(name);
+        res.start();
+        return res;
+    }
+
+    private void handle(WebSocket ws, Debugger debugger) {
+        WebSocketMessage raw;
+
+        debugger.connect();
+
+        while ((raw = ws.receive()) != null) {
+            if (raw.type != Type.Text) {
+                ws.send(new V8Error("Expected a text message."));
+                continue;
+            }
+
+            V8Message msg;
+
+            try {
+                msg = new V8Message(raw.textData());
+            }
+            catch (SyntaxException e) {
+                ws.send(new V8Error(e.getMessage()));
+                return;
+            }
+
+            try {
+                switch (msg.name) {
+                    case "Debugger.enable":
+                        connNotifier.next();
+                        debugger.enable(msg); continue;
+                    case "Debugger.disable": debugger.disable(msg); continue;
+
+                    case "Debugger.setBreakpoint": debugger.setBreakpoint(msg); continue;
+                    case "Debugger.setBreakpointByUrl": debugger.setBreakpointByUrl(msg); continue;
+                    case "Debugger.removeBreakpoint": debugger.removeBreakpoint(msg); continue;
+                    case "Debugger.continueToLocation": debugger.continueToLocation(msg); continue;
+
+                    case "Debugger.getScriptSource": debugger.getScriptSource(msg); continue;
+                    case "Debugger.getPossibleBreakpoints": debugger.getPossibleBreakpoints(msg); continue;
+
+                    case "Debugger.resume": debugger.resume(msg); continue;
+                    case "Debugger.pause": debugger.pause(msg); continue;
+
+                    case "Debugger.stepInto": debugger.stepInto(msg); continue;
+                    case "Debugger.stepOut": debugger.stepOut(msg); continue;
+                    case "Debugger.stepOver": debugger.stepOver(msg); continue;
+
+                    case "Debugger.setPauseOnExceptions": debugger.setPauseOnExceptions(msg); continue;
+                    case "Debugger.evaluateOnCallFrame": debugger.evaluateOnCallFrame(msg); continue;
+
+                    case "Runtime.releaseObjectGroup": debugger.releaseObjectGroup(msg); continue;
+                    case "Runtime.releaseObject": debugger.releaseObject(msg); continue;
+                    case "Runtime.getProperties": debugger.getProperties(msg); continue;
+                    case "Runtime.callFunctionOn": debugger.callFunctionOn(msg); continue;
+                    // case "NodeWorker.enable": debugger.nodeWorkerEnable(msg); continue;
+                    case "Runtime.enable": debugger.runtimeEnable(msg); continue;
+                }
+
+                if (
+                    msg.name.startsWith("DOM.") ||
+                    msg.name.startsWith("DOMDebugger.") ||
+                    msg.name.startsWith("Emulation.") ||
+                    msg.name.startsWith("Input.") ||
+                    msg.name.startsWith("Network.") ||
+                    msg.name.startsWith("Page.")
+                ) ws.send(new V8Error("This isn't a browser..."));
+                else ws.send(new V8Error("This API is not supported yet."));
+            }
+            catch (Throwable e) {
+                e.printStackTrace();
+                throw new UncheckedException(e);
+            }
+        }
+
+        debugger.disconnect();
+    }
+    private void onWsConnect(HttpRequest req, Socket socket, DebuggerProvider debuggerProvider) {
+        var key = req.headers.get("sec-websocket-key");
+
+        if (key == null) {
+            req.writeResponse(
+                426, "Upgrade Required", "text/txt",
+                "Expected a WS upgrade".getBytes()
+            );
+            return;
+        }
+
+        var resKey = Base64.getEncoder().encodeToString(getDigestInstance().digest(
+            (key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes()
+        ));
+
+        req.writeCode(101, "Switching Protocols");
+        req.writeHeader("Connection", "Upgrade");
+        req.writeHeader("Sec-WebSocket-Accept", resKey);
+        req.writeLastHeader("Upgrade", "WebSocket");
+
+        var ws = new WebSocket(socket);
+        var debugger = debuggerProvider.getDebugger(ws, req);
+
+        if (debugger == null) {
+            ws.close();
+            return;
+        }
+
+        runAsync(() -> {
+            try { handle(ws, debugger); }
+            catch (RuntimeException e) {
+                ws.send(new V8Error(e.getMessage()));
+            }
+            finally { ws.close(); debugger.disconnect(); }
+        }, "Debug Handler");
+    }
+
+    public void awaitConnection() {
+        connNotifier.await();
+    }
+
+    public void run(InetSocketAddress address) {
+        try {
+            ServerSocket server = new ServerSocket();
+            server.bind(address);
+
+            try {
+                while (true) {
+                    var socket = server.accept();
+                    var req = HttpRequest.read(socket);
+
+                    if (req == null) continue;
+    
+                    switch (req.path) {
+                        case "/json/version":
+                            send(req, "{\"Browser\":\"" + browserDisplayName + "\",\"Protocol-Version\":\"1.1\"}");
+                            break;
+                        case "/json/list":
+                        case "/json": {
+                            var res = new JSONList();
+
+                            for (var el : targets.entrySet()) {
+                                res.add(new JSONMap()
+                                    .set("description", "JScript debugger")
+                                    .set("favicon", "/favicon.ico")
+                                    .set("id", el.getKey())
+                                    .set("type", "node")
+                                    .set("webSocketDebuggerUrl", "ws://" + address.getHostString() + ":" + address.getPort() + "/" + el.getKey())
+                                );
+                            }
+                            send(req, JSON.stringify(res));
+                            break;
+                        }
+                        case "/json/protocol":
+                            req.writeResponse(200, "OK", "application/json", protocol);
+                            break;
+                        case "/json/new":
+                        case "/json/activate":
+                        case "/json/close":
+                        case "/devtools/inspector.html":
+                            req.writeResponse(
+                                501, "Not Implemented", "text/txt",
+                                "This feature isn't (and probably won't be) implemented.".getBytes()
+                            );
+                            break;
+                        case "/":
+                        case "/index.html":
+                            req.writeResponse(200, "OK", "text/html", index);
+                            break;
+                        case "/favicon.ico":
+                            req.writeResponse(200, "OK", "image/png", favicon);
+                            break;
+                        default:
+                            if (req.path.length() > 1 && targets.containsKey(req.path.substring(1))) {
+                                onWsConnect(req, socket, targets.get(req.path.substring(1)));
+                            }
+                            break;
+                    }
+                }
+            }
+            finally { server.close(); }
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+
+    public Thread start(InetSocketAddress address, boolean daemon) {
+        var res = new Thread(() -> run(address), "Debug Server");
+        res.setDaemon(daemon);
+        res.start();
+        return res;
+    }
+
+    public DebugServer() {
+        try {
+            this.favicon = getClass().getClassLoader().getResourceAsStream("assets/favicon.png").readAllBytes();
+            this.protocol = getClass().getClassLoader().getResourceAsStream("assets/protocol.json").readAllBytes();
+            var index = new String(getClass().getClassLoader().getResourceAsStream("assets/index.html").readAllBytes());
+            this.index = index
+                .replace("${NAME}", Metadata.name())
+                .replace("${VERSION}", Metadata.version())
+                .replace("${AUTHOR}", Metadata.author())
+                .getBytes();
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/Debugger.java
+++ b/src/me/topchetoeu/jscript/engine/debug/Debugger.java
@@ -0,0 +1,6 @@
+package me.topchetoeu.jscript.engine.debug;
+
+public interface Debugger extends DebugHandler, DebugController {
+    void connect();
+    void disconnect();
+}
--- a/src/me/topchetoeu/jscript/engine/debug/DebuggerProvider.java
+++ b/src/me/topchetoeu/jscript/engine/debug/DebuggerProvider.java
@@ -0,0 +1,5 @@
+package me.topchetoeu.jscript.engine.debug;
+
+public interface DebuggerProvider {
+    Debugger getDebugger(WebSocket socket, HttpRequest req);
+}
--- a/src/me/topchetoeu/jscript/engine/debug/HttpRequest.java
+++ b/src/me/topchetoeu/jscript/engine/debug/HttpRequest.java
@@ -0,0 +1,102 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.util.HashMap;
+import java.util.IllegalFormatException;
+import java.util.Map;
+
+public class HttpRequest {
+    public final String method;
+    public final String path;
+    public final Map<String, String> headers;
+    public final OutputStream out;
+
+
+    public void writeCode(int code, String name) {
+        try { out.write(("HTTP/1.1 " + code + " " + name + "\r\n").getBytes()); }
+        catch (IOException e) { }
+    }
+    public void writeHeader(String name, String value) {
+        try { out.write((name + ": " + value + "\r\n").getBytes()); }
+        catch (IOException e) { }
+    }
+    public void writeLastHeader(String name, String value) {
+        try { out.write((name + ": " + value + "\r\n\r\n").getBytes()); }
+        catch (IOException e) { }
+    }
+    public void writeHeadersEnd() {
+        try { out.write("\n".getBytes()); }
+        catch (IOException e) { }
+    }
+
+    public void writeResponse(int code, String name, String type, byte[] data) {
+        writeCode(code, name);
+        writeHeader("Content-Type", type);
+        writeLastHeader("Content-Length", data.length + "");
+        try {
+            out.write(data);
+            out.close();
+        }
+        catch (IOException e) { }
+    }
+    public void writeResponse(int code, String name, String type, InputStream data) {
+        try {
+            writeResponse(code, name, type, data.readAllBytes());
+        }
+        catch (IOException e) { }
+    }
+
+    public HttpRequest(String method, String path, Map<String, String> headers, OutputStream out) {
+        this.method = method;
+        this.path = path;
+        this.headers = headers;
+        this.out = out;
+    }
+
+    // We dont need no http library
+    public static HttpRequest read(Socket socket) {
+        try {
+            var str = socket.getInputStream();
+            var lines = new BufferedReader(new InputStreamReader(str));
+            var line = lines.readLine();
+            var i1 = line.indexOf(" ");
+            var i2 = line.indexOf(" ", i1 + 1);
+
+            if (i1 < 0 || i2 < 0) {
+                socket.close();
+                return null;
+            }
+
+            var method = line.substring(0, i1).trim().toUpperCase();
+            var path = line.substring(i1 + 1, i2).trim();
+            var headers = new HashMap<String, String>();
+
+            while (!(line = lines.readLine()).isEmpty()) {
+                var i = line.indexOf(":");
+                if (i < 0) continue;
+                var name = line.substring(0, i).trim().toLowerCase();
+                var value = line.substring(i + 1).trim();
+
+                if (name.length() == 0) continue;
+                headers.put(name, value);
+            }
+
+            if (headers.containsKey("content-length")) {
+                try {
+                    var i = Integer.parseInt(headers.get("content-length"));
+                    str.skip(i);
+                }
+                catch (IllegalFormatException e) { /* ¯\_(ツ)_/¯ */ }
+            }
+
+            return new HttpRequest(method, path, headers, socket.getOutputStream());
+        }
+        catch (IOException | NullPointerException e) { return null; }
+    }
+}
+
--- a/src/me/topchetoeu/jscript/engine/debug/SimpleDebugger.java
+++ b/src/me/topchetoeu/jscript/engine/debug/SimpleDebugger.java
@@ -0,0 +1,813 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.TreeSet;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.Instruction;
+import me.topchetoeu.jscript.compilation.Instruction.Type;
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.Engine;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.engine.frame.Runners;
+import me.topchetoeu.jscript.engine.scope.GlobalScope;
+import me.topchetoeu.jscript.engine.values.ArrayValue;
+import me.topchetoeu.jscript.engine.values.CodeFunction;
+import me.topchetoeu.jscript.engine.values.FunctionValue;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.engine.values.Symbol;
+import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.events.Notifier;
+import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONElement;
+import me.topchetoeu.jscript.json.JSONList;
+import me.topchetoeu.jscript.json.JSONMap;
+
+// very simple indeed
+public class SimpleDebugger implements Debugger {
+    public static final String CHROME_GET_PROP_FUNC = "function s(e){let t=this;const n=JSON.parse(e);for(let e=0,i=n.length;e<i;++e)t=t[n[e]];return t}";
+    public static final String VSCODE_STRINGIFY_VAL = "function(...runtimeArgs){\n    let t = 1024; let e = null;\n    if(e)try{let r=\"<<default preview>>\",i=e.call(this,r);if(i!==r)return String(i)}catch(r){return`<<indescribable>>${JSON.stringify([String(r),\"object\"])}`}if(typeof this==\"object\"&&this){let r;for(let i of[Symbol.for(\"debug.description\"),Symbol.for(\"nodejs.util.inspect.custom\")])try{r=this[i]();break}catch{}if(!r&&!String(this.toString).includes(\"[native code]\")&&(r=String(this)),r&&!r.startsWith(\"[object \"))return r.length>=t?r.slice(0,t)+\"\\u2026\":r}\n  ;\n\n}";
+    public static final String VSCODE_STRINGIFY_PROPS = "function(...runtimeArgs){\n    let t = 1024; let e = null;\n    let r={},i=\"<<default preview>>\";if(typeof this!=\"object\"||!this)return r;for(let[n,s]of Object.entries(this)){if(e)try{let o=e.call(s,i);if(o!==i){r[n]=String(o);continue}}catch(o){r[n]=`<<indescribable>>${JSON.stringify([String(o),n])}`;continue}if(typeof s==\"object\"&&s){let o;for(let a of runtimeArgs[0])try{o=s[a]();break}catch{}!o&&!String(s.toString).includes(\"[native code]\")&&(o=String(s)),o&&!o.startsWith(\"[object \")&&(r[n]=o.length>=t?o.slice(0,t)+\"\\u2026\":o)}}return r\n  ;\n\n}";
+    public static final String VSCODE_SYMBOL_REQUEST = "function(){return[Symbol.for(\"debug.description\"),Symbol.for(\"nodejs.util.inspect.custom\")]\n}";
+    public static final String VSCODE_SHALLOW_COPY = "function(){let t={__proto__:this.__proto__\n},e=Object.getOwnPropertyNames(this);for(let r=0;r<e.length;++r){let i=e[r],n=i>>>0;if(String(n>>>0)===i&&n>>>0!==4294967295)continue;let s=Object.getOwnPropertyDescriptor(this,i);s&&Object.defineProperty(t,i,s)}return t}";
+    public static final String VSCODE_FLATTEN_ARRAY = "function(t,e){let r={\n},i=t===-1?0:t,n=e===-1?this.length:t+e;for(let s=i;s<n&&s<this.length;++s){let o=Object.getOwnPropertyDescriptor(this,s);o&&Object.defineProperty(r,s,o)}return r}";
+    public static final String VSCODE_CALL = "function(t){return t.call(this)\n}";
+
+    private static enum State {
+        RESUMED,
+        STEPPING_IN,
+        STEPPING_OUT,
+        STEPPING_OVER,
+        PAUSED_NORMAL,
+        PAUSED_EXCEPTION,
+    }
+    private static enum CatchType {
+        NONE,
+        UNCAUGHT,
+        ALL,
+    }
+    private static class Source {
+        public final int id;
+        public final Filename filename;
+        public final String source;
+        public final TreeSet<Location> breakpoints;
+
+        public Source(int id, Filename filename, String source, TreeSet<Location> breakpoints) {
+            this.id = id;
+            this.filename = filename;
+            this.source = source;
+            this.breakpoints = breakpoints;
+        }
+    }
+    private static class Breakpoint {
+        public final int id;
+        public final Location location;
+        public final String condition;
+
+        public Breakpoint(int id, Location location, String condition) {
+            this.id = id;
+            this.location = location;
+            this.condition = condition;
+        }
+    }
+    private static class BreakpointCandidate {
+        public final int id;
+        public final String condition;
+        public final Pattern pattern;
+        public final int line, start;
+        public final HashSet<Breakpoint> resolvedBreakpoints = new HashSet<>();
+
+        public BreakpointCandidate(int id, Pattern pattern, int line, int start, String condition) {
+            this.id = id;
+            this.pattern = pattern;
+            this.line = line;
+            this.start = start;
+            if (condition != null && condition.trim().equals("")) condition = null;
+            this.condition = condition;
+        }
+    }
+    private class Frame {
+        public CodeFrame frame;
+        public CodeFunction func;
+        public int id;
+        public ObjectValue local, capture, global, valstack;
+        public JSONMap serialized;
+        public Location location;
+        public boolean debugData = false;
+
+        public void updateLoc(Location loc) {
+            serialized.set("location", serializeLocation(loc));
+            this.location = loc;
+        }
+
+        public Frame(Context ctx, CodeFrame frame, int id) {
+            this.frame = frame;
+            this.func = frame.function;
+            this.id = id;
+            this.location = frame.function.loc();
+
+            this.global = frame.function.environment.global.obj;
+            this.local = frame.getLocalScope(ctx, true);
+            this.capture = frame.getCaptureScope(ctx, true);
+            this.local.setPrototype(ctx, capture);
+            this.capture.setPrototype(ctx, global);
+            this.valstack = frame.getValStackScope(ctx);
+
+            if (location != null) {
+                debugData = true;
+                this.serialized = new JSONMap()
+                    .set("callFrameId", id + "")
+                    .set("functionName", func.name)
+                    .set("location", serializeLocation(location))
+                    .set("scopeChain", new JSONList()
+                        .add(new JSONMap().set("type", "local").set("name", "Local Scope").set("object", serializeObj(ctx, local)))
+                        .add(new JSONMap().set("type", "closure").set("name", "Closure").set("object", serializeObj(ctx, capture)))
+                        .add(new JSONMap().set("type", "global").set("name", "Global Scope").set("object", serializeObj(ctx, global)))
+                        .add(new JSONMap().set("type", "other").set("name", "Value Stack").set("object", serializeObj(ctx, valstack)))
+                    );
+            }
+        }
+    }
+
+    private static class RunResult {
+        public final Context ctx;
+        public final Object result;
+        public final EngineException error;
+
+        public RunResult(Context ctx, Object result, EngineException error) {
+            this.ctx = ctx;
+            this.result = result;
+            this.error = error;
+        }
+    }
+
+    public boolean enabled = true;
+    public CatchType execptionType = CatchType.ALL; 
+    public State state = State.RESUMED;
+
+    public final WebSocket ws;
+    public final Engine target;
+
+    private ObjectValue emptyObject = new ObjectValue();
+
+    private HashMap<Integer, BreakpointCandidate> idToBptCand = new HashMap<>();
+
+    private HashMap<Integer, Breakpoint> idToBreakpoint = new HashMap<>();
+    private HashMap<Location, Breakpoint> locToBreakpoint = new HashMap<>();
+    private HashSet<Location> tmpBreakpts = new HashSet<>();
+
+    private HashMap<Filename, Integer> filenameToId = new HashMap<>();
+    private HashMap<Integer, Source> idToSource = new HashMap<>();
+    private ArrayList<Source> pendingSources = new ArrayList<>();
+
+    private HashMap<Integer, Frame> idToFrame = new HashMap<>();
+    private HashMap<CodeFrame, Frame> codeFrameToFrame = new HashMap<>();
+
+    private HashMap<Integer, ObjectValue> idToObject = new HashMap<>();
+    private HashMap<ObjectValue, Integer> objectToId = new HashMap<>();
+    private HashMap<ObjectValue, Context> objectToCtx = new HashMap<>();
+    private HashMap<String, ArrayList<ObjectValue>> objectGroups = new HashMap<>();
+
+    private Notifier updateNotifier = new Notifier(); 
+
+    private int nextId = new Random().nextInt() & 0x7FFFFFFF;
+    private Location prevLocation = null;
+    private Frame stepOutFrame = null, currFrame = null;
+
+    private int nextId() {
+        return nextId++ ^ 1630022591 /* big prime */;
+    }
+
+    private void updateFrames(Context ctx) {
+        var frame = ctx.peekFrame();
+        if (frame == null) return;
+
+        if (!codeFrameToFrame.containsKey(frame)) {
+            var id = nextId();
+            var fr = new Frame(ctx, frame, id);
+
+            idToFrame.put(id, fr);
+            codeFrameToFrame.put(frame, fr);
+        }
+
+        currFrame = codeFrameToFrame.get(frame);
+    }
+    private JSONList serializeFrames(Context ctx) {
+        var res = new JSONList();
+        var frames = ctx.frames();
+
+        for (var i = frames.size() - 1; i >= 0; i--) {
+            res.add(codeFrameToFrame.get(frames.get(i)).serialized);
+        }
+
+        return res;
+    }
+
+    private Location correctLocation(Source source, Location loc) {
+        var set = source.breakpoints;
+
+        if (set.contains(loc)) return loc;
+
+        var tail = set.tailSet(loc);
+        if (tail.isEmpty()) return null;
+
+        return tail.first();
+    }
+    private Location deserializeLocation(JSONElement el, boolean correct) {
+        if (!el.isMap()) throw new RuntimeException("Expected location to be a map.");
+        var id = Integer.parseInt(el.map().string("scriptId"));
+        var line = (int)el.map().number("lineNumber") + 1;
+        var column = (int)el.map().number("columnNumber") + 1;
+
+        if (!idToSource.containsKey(id)) throw new RuntimeException(String.format("The specified source %s doesn't exist.", id));
+
+        var res = new Location(line, column, idToSource.get(id).filename);
+        if (correct) res = correctLocation(idToSource.get(id), res);
+        return res;
+    }
+    private JSONMap serializeLocation(Location loc) {
+        var source = filenameToId.get(loc.filename());
+        return new JSONMap()
+            .set("scriptId", source + "")
+            .set("lineNumber", loc.line() - 1)
+            .set("columnNumber", loc.start() - 1);
+    }
+
+    private Integer objectId(Context ctx, ObjectValue obj) {
+        if (objectToId.containsKey(obj)) return objectToId.get(obj);
+        else {
+            int id = nextId();
+            objectToId.put(obj, id);
+            if (ctx != null) objectToCtx.put(obj, ctx);
+            idToObject.put(id, obj);
+            return id;
+        }
+    }
+    private JSONMap serializeObj(Context ctx, Object val) {
+        val = Values.normalize(null, val);
+
+        if (val == Values.NULL) {
+            return new JSONMap()
+                .set("type", "object")
+                .set("subtype", "null")
+                .setNull("value")
+                .set("description", "null");
+        }
+
+        if (val instanceof ObjectValue) {
+            var obj = (ObjectValue)val;
+            var id = objectId(ctx, obj);
+            var type = "object";
+            String subtype = null;
+            String className = null;
+
+            if (obj instanceof FunctionValue) type = "function";
+            if (obj instanceof ArrayValue) subtype = "array";
+
+            try { className = Values.toString(ctx, Values.getMember(ctx, obj.getMember(ctx, "constructor"), "name")); }
+            catch (Exception e) { }
+
+            var res = new JSONMap()
+                .set("type", type)
+                .set("objectId", id + "");
+
+            if (subtype != null) res.set("subtype", subtype);
+            if (className != null) {
+                res.set("className", className);
+                res.set("description", "{ " + className + " }");
+            }
+
+            return res;
+        }
+
+        if (val == null) return new JSONMap().set("type", "undefined");
+        if (val instanceof String) return new JSONMap().set("type", "string").set("value", (String)val);
+        if (val instanceof Boolean) return new JSONMap().set("type", "boolean").set("value", (Boolean)val);
+        if (val instanceof Symbol) return new JSONMap().set("type", "symbol").set("description", val.toString());
+        if (val instanceof Number) {
+            var num = (double)(Number)val;
+            var res = new JSONMap().set("type", "number");
+
+            if (Double.POSITIVE_INFINITY == num) res.set("unserializableValue", "Infinity");
+            else if (Double.NEGATIVE_INFINITY == num) res.set("unserializableValue", "-Infinity");
+            else if (Double.doubleToRawLongBits(num) == Double.doubleToRawLongBits(-0d)) res.set("unserializableValue", "-0");
+            else if (Double.doubleToRawLongBits(num) == Double.doubleToRawLongBits(0d)) res.set("unserializableValue", "0");
+            else if (Double.isNaN(num)) res.set("unserializableValue", "NaN");
+            else res.set("value", num);
+
+            return res;
+        }
+
+        throw new IllegalArgumentException("Unexpected JS object.");
+    }
+    private void setObjectGroup(String name, Object val) {
+        if (val instanceof ObjectValue) {
+            var obj = (ObjectValue)val;
+
+            if (objectGroups.containsKey(name)) objectGroups.get(name).add(obj);
+            else objectGroups.put(name, new ArrayList<>(List.of(obj)));
+        }
+    }
+    private void releaseGroup(String name) {
+        var objs = objectGroups.remove(name);
+
+        if (objs != null) {
+            for (var obj : objs) {
+                var id = objectToId.remove(obj);
+                if (id != null) idToObject.remove(id);
+            }
+        }
+    }
+    private Object deserializeArgument(JSONMap val) {
+        if (val.isString("objectId")) return idToObject.get(Integer.parseInt(val.string("objectId")));
+        else if (val.isString("unserializableValue")) switch (val.string("unserializableValue")) {
+            case "NaN": return Double.NaN;
+            case "-Infinity": return Double.NEGATIVE_INFINITY;
+            case "Infinity": return Double.POSITIVE_INFINITY;
+            case "-0": return -0.;
+        }
+        return JSON.toJs(val.get("value"));
+    }
+
+    private JSONMap serializeException(Context ctx, EngineException err) {
+        String text = null;
+
+        try {
+            text = Values.toString(ctx, err.value);
+        }
+        catch (EngineException e) {
+            text = "[error while stringifying]";
+        }
+
+        var res = new JSONMap()
+            .set("exceptionId", nextId())
+            .set("exception", serializeObj(ctx, err.value))
+            .set("exception", serializeObj(ctx, err.value))
+            .set("text", text);
+
+        return res;
+    }
+
+    private void resume(State state) {
+        this.state = state;
+        ws.send(new V8Event("Debugger.resumed", new JSONMap()));
+        updateNotifier.next();
+    }
+    private void pauseDebug(Context ctx, Breakpoint bp) {
+        state = State.PAUSED_NORMAL;
+        var map = new JSONMap()
+            .set("callFrames", serializeFrames(ctx))
+            .set("reason", "debugCommand");
+
+        if (bp != null) map.set("hitBreakpoints", new JSONList().add(bp.id + ""));
+        ws.send(new V8Event("Debugger.paused", map));
+    }
+    private void pauseException(Context ctx) {
+        state = State.PAUSED_EXCEPTION;
+        var map = new JSONMap()
+            .set("callFrames", serializeFrames(ctx))
+            .set("reason", "exception");
+
+        ws.send(new V8Event("Debugger.paused", map));
+    }
+
+    private void sendSource(Source src) {
+        ws.send(new V8Event("Debugger.scriptParsed", new JSONMap()
+            .set("scriptId", src.id + "")
+            .set("hash", src.source.hashCode())
+            .set("url", src.filename + "")
+        ));
+    }
+
+    private void addBreakpoint(Breakpoint bpt) {
+        idToBreakpoint.put(bpt.id, bpt);
+        locToBreakpoint.put(bpt.location, bpt);
+
+        ws.send(new V8Event("Debugger.breakpointResolved", new JSONMap()
+            .set("breakpointId", bpt.id)
+            .set("location", serializeLocation(bpt.location))
+        ));
+    }
+
+    private RunResult run(Frame codeFrame, String code) {
+        var engine = new Engine(false);
+        var env = codeFrame.func.environment.fork();
+
+        ObjectValue global = env.global.obj,
+            capture = codeFrame.frame.getCaptureScope(null, enabled),
+            local = codeFrame.frame.getLocalScope(null, enabled);
+
+        capture.setPrototype(null, global);
+        local.setPrototype(null, capture);
+        env.global = new GlobalScope(local);
+
+        var ctx = new Context(engine).pushEnv(env);
+        var awaiter = engine.pushMsg(false, ctx, new Filename("jscript", "eval"), code, codeFrame.frame.thisArg, codeFrame.frame.args);
+
+        engine.run(true);
+
+        try { return new RunResult(ctx, awaiter.await(), null); }
+        catch (EngineException e) { return new RunResult(ctx, null, e); }
+    }
+
+    @Override public void enable(V8Message msg) {
+        enabled = true;
+        ws.send(msg.respond());
+
+        for (var el : pendingSources) sendSource(el);
+        pendingSources.clear();
+
+        updateNotifier.next();
+    }
+    @Override public void disable(V8Message msg) {
+        enabled = false;
+        ws.send(msg.respond());
+        updateNotifier.next();
+    }
+
+    @Override public void getScriptSource(V8Message msg) {
+        int id = Integer.parseInt(msg.params.string("scriptId"));
+        ws.send(msg.respond(new JSONMap().set("scriptSource", idToSource.get(id).source)));
+    }
+    @Override public void getPossibleBreakpoints(V8Message msg) {
+        var src = idToSource.get(Integer.parseInt(msg.params.map("start").string("scriptId")));
+        var start = deserializeLocation(msg.params.get("start"), false);
+        var end = msg.params.isMap("end") ? deserializeLocation(msg.params.get("end"), false) : null;
+
+        var res = new JSONList();
+
+        for (var loc : src.breakpoints.tailSet(start, true)) {
+            if (end != null && loc.compareTo(end) > 0) break;
+            res.add(serializeLocation(loc));
+        }
+
+        ws.send(msg.respond(new JSONMap().set("locations", res)));
+    }
+
+    @Override public void pause(V8Message msg) {
+    }
+
+    @Override public void resume(V8Message msg) {
+        resume(State.RESUMED);
+        ws.send(msg.respond(new JSONMap()));
+    }
+
+    @Override public void setBreakpoint(V8Message msg) {
+        // int id = nextId();
+        // var loc = deserializeLocation(msg.params.get("location"), true);
+        // var bpt = new Breakpoint(id, loc, null);
+        // breakpoints.put(loc, bpt);
+        // idToBrpt.put(id, bpt);
+        // ws.send(msg.respond(new JSONMap()
+        //     .set("breakpointId", id)
+        //     .set("actualLocation", serializeLocation(loc))
+        // ));
+    }
+    @Override public void setBreakpointByUrl(V8Message msg) {
+        var line = (int)msg.params.number("lineNumber") + 1;
+        var col = (int)msg.params.number("columnNumber", 0) + 1;
+        var cond = msg.params.string("condition", "").trim();
+
+        if (cond.equals("")) cond = null;
+        if (cond != null) cond  = "(" + cond + ")";
+
+        Pattern regex;
+
+        if (msg.params.isString("url")) regex = Pattern.compile(Pattern.quote(msg.params.string("url")));
+        else regex = Pattern.compile(msg.params.string("urlRegex"));
+
+        var bpcd = new BreakpointCandidate(nextId(), regex, line, col, cond);
+        idToBptCand.put(bpcd.id, bpcd);
+
+        var locs = new JSONList();
+
+        for (var src : idToSource.values()) {
+            if (regex.matcher(src.filename.toString()).matches()) {
+                var loc = correctLocation(src, new Location(line, col, src.filename));
+                if (loc == null) continue;
+                var bp = new Breakpoint(nextId(), loc, bpcd.condition);
+
+                bpcd.resolvedBreakpoints.add(bp);
+                locs.add(serializeLocation(loc));
+                addBreakpoint(bp);
+            }
+        }
+
+        ws.send(msg.respond(new JSONMap()
+            .set("breakpointId", bpcd.id + "")
+            .set("locations", locs)
+        ));
+    }
+    @Override public void removeBreakpoint(V8Message msg) {
+        var id = Integer.parseInt(msg.params.string("breakpointId"));
+
+        if (idToBptCand.containsKey(id)) {
+            var bpcd = idToBptCand.get(id);
+            for (var bp : bpcd.resolvedBreakpoints) {
+                idToBreakpoint.remove(bp.id);
+                locToBreakpoint.remove(bp.location);
+            }
+            idToBptCand.remove(id);
+        }
+        else if (idToBreakpoint.containsKey(id)) {
+            var bp = idToBreakpoint.remove(id);
+            locToBreakpoint.remove(bp.location);
+        }
+        ws.send(msg.respond());
+    }
+    @Override public void continueToLocation(V8Message msg) {
+        var loc = deserializeLocation(msg.params.get("location"), true);
+
+        tmpBreakpts.add(loc);
+
+        resume(State.RESUMED);
+        ws.send(msg.respond());
+    }
+
+    @Override public void setPauseOnExceptions(V8Message msg) {
+        ws.send(new V8Error("i dont wanna to"));
+    }
+
+    @Override public void stepInto(V8Message msg) {
+        if (state == State.RESUMED) ws.send(new V8Error("Debugger is resumed."));
+        else {
+            prevLocation = currFrame.location;
+            stepOutFrame = currFrame;
+            resume(State.STEPPING_IN);
+            ws.send(msg.respond());
+        }
+    }
+    @Override public void stepOut(V8Message msg) {
+        if (state == State.RESUMED) ws.send(new V8Error("Debugger is resumed."));
+        else {
+            prevLocation = currFrame.location;
+            stepOutFrame = currFrame;
+            resume(State.STEPPING_OUT);
+            ws.send(msg.respond());
+        }
+    }
+    @Override public void stepOver(V8Message msg) {
+        if (state == State.RESUMED) ws.send(new V8Error("Debugger is resumed."));
+        else {
+            prevLocation = currFrame.location;
+            stepOutFrame = currFrame;
+            resume(State.STEPPING_OVER);
+            ws.send(msg.respond());
+        }
+    }
+
+    @Override public void evaluateOnCallFrame(V8Message msg) {
+        var cfId = Integer.parseInt(msg.params.string("callFrameId"));
+        var expr = msg.params.string("expression");
+        var group = msg.params.string("objectGroup", null);
+
+        var cf = idToFrame.get(cfId);
+        var res = run(cf, expr);
+
+        if (group != null) setObjectGroup(group, res.result);
+
+        if (res.error != null) ws.send(msg.respond(new JSONMap().set("exceptionDetails", serializeObj(res.ctx, res.result))));
+
+        ws.send(msg.respond(new JSONMap().set("result", serializeObj(res.ctx, res.result))));
+    }
+
+    @Override public void releaseObjectGroup(V8Message msg) {
+        var group = msg.params.string("objectGroup");
+        releaseGroup(group);
+        ws.send(msg.respond());
+    }
+    @Override
+    public void releaseObject(V8Message msg) {
+        var id = Integer.parseInt(msg.params.string("objectId"));
+        var obj = idToObject.remove(id);
+        if (obj != null) objectToId.remove(obj);
+        ws.send(msg.respond());
+    }
+    @Override public void getProperties(V8Message msg) {
+        var obj = idToObject.get(Integer.parseInt(msg.params.string("objectId")));
+
+        var res = new JSONList();
+        var ctx = objectToCtx.get(obj);
+
+        if (obj != emptyObject) {
+            for (var key : obj.keys(true)) {
+                var propDesc = new JSONMap();
+
+                if (obj.properties.containsKey(key)) {
+                    var prop = obj.properties.get(key);
+
+                    propDesc.set("name", Values.toString(ctx, key));
+                    if (prop.getter != null) propDesc.set("get", serializeObj(ctx, prop.getter));
+                    if (prop.setter != null) propDesc.set("set", serializeObj(ctx, prop.setter));
+                    propDesc.set("enumerable", obj.memberEnumerable(key));
+                    propDesc.set("configurable", obj.memberConfigurable(key));
+                    propDesc.set("isOwn", true);
+                    res.add(propDesc);
+                }
+                else {
+                    propDesc.set("name", Values.toString(ctx, key));
+                    propDesc.set("value", serializeObj(ctx, obj.getMember(ctx, key)));
+                    propDesc.set("writable", obj.memberWritable(key));
+                    propDesc.set("enumerable", obj.memberEnumerable(key));
+                    propDesc.set("configurable", obj.memberConfigurable(key));
+                    propDesc.set("isOwn", true);
+                    res.add(propDesc);
+                }
+            }
+    
+            var proto = obj.getPrototype(ctx);
+    
+            var protoDesc = new JSONMap();
+            protoDesc.set("name", "__proto__");
+            protoDesc.set("value", serializeObj(ctx, proto == null ? Values.NULL : proto));
+            protoDesc.set("writable", true);
+            protoDesc.set("enumerable", false);
+            protoDesc.set("configurable", false);
+            protoDesc.set("isOwn", true);
+            res.add(protoDesc);
+        }
+
+        ws.send(msg.respond(new JSONMap().set("result", res)));
+    }
+    @Override public void callFunctionOn(V8Message msg) {
+        var src = msg.params.string("functionDeclaration");
+        var args = msg.params
+            .list("arguments", new JSONList())
+            .stream()
+            .map(v -> v.map())
+            .map(this::deserializeArgument)
+            .collect(Collectors.toList());
+
+        var thisArg = idToObject.get(Integer.parseInt(msg.params.string("objectId")));
+        var ctx = objectToCtx.get(thisArg);
+
+        while (true) {
+            var start = src.lastIndexOf("//# sourceURL=");
+            if (start < 0) break;
+            var end = src.indexOf("\n", start);
+            if (end < 0) src = src.substring(0, start);
+            else src = src.substring(0, start) + src.substring(end + 1);
+        }
+
+        try {
+            switch (src) {
+                case CHROME_GET_PROP_FUNC: {
+                    var path = JSON.parse(null, (String)args.get(0)).list();
+                    Object res = thisArg;
+                    for (var el : path) res = Values.getMember(ctx, res, JSON.toJs(el));
+                    ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, res))));
+                    return;
+                }
+                case VSCODE_STRINGIFY_VAL:
+                case VSCODE_STRINGIFY_PROPS:
+                case VSCODE_SHALLOW_COPY:
+                case VSCODE_SYMBOL_REQUEST:
+                    ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, emptyObject))));
+                    break;
+                case VSCODE_FLATTEN_ARRAY:
+                    ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, thisArg))));
+                    break;
+                case VSCODE_CALL: {
+                    var func = (FunctionValue)(args.size() < 1 ? null : args.get(0));
+                    ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, func.call(ctx, thisArg)))));
+                    break;
+                }
+                default:
+                    ws.send(new V8Error("Please use well-known functions with callFunctionOn"));
+                    break;
+                // default: {
+                //     var res = ctx.compile(new Filename("jscript", "eval"), src).call(ctx);
+                //     if (res instanceof FunctionValue) ((FunctionValue)res).call(ctx, thisArg, args);
+                //     ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, res))));
+                // }
+            }
+        }
+        catch (EngineException e) { ws.send(msg.respond(new JSONMap().set("exceptionDetails", serializeException(ctx, e)))); }
+    }
+
+    @Override
+    public void runtimeEnable(V8Message msg) {
+        ws.send(msg.respond());
+    }
+
+    @Override public void onSource(Filename filename, String source, TreeSet<Location> locations) {
+        int id = nextId();
+        var src = new Source(id, filename, source, locations);
+
+        idToSource.put(id, src);
+        filenameToId.put(filename, id);
+
+        for (var bpcd : idToBptCand.values()) {
+            if (!bpcd.pattern.matcher(filename.toString()).matches()) continue;
+            var loc = correctLocation(src, new Location(bpcd.line, bpcd.start, filename));
+            var bp = new Breakpoint(nextId(), loc, bpcd.condition);
+            if (loc == null) continue;
+            bpcd.resolvedBreakpoints.add(bp);
+            addBreakpoint(bp);
+        }
+
+        if (!enabled) pendingSources.add(src);
+        else sendSource(src);
+    }
+    @Override public boolean onInstruction(Context ctx, CodeFrame cf, Instruction instruction, Object returnVal, EngineException error, boolean caught) {
+        if (!enabled) return false;
+
+        updateFrames(ctx);
+        var frame = codeFrameToFrame.get(cf);
+
+        if (!frame.debugData) return false;
+
+        if (instruction.location != null) frame.updateLoc(instruction.location);
+        var loc = frame.location;
+        var isBreakpointable = loc != null && (
+            idToSource.get(filenameToId.get(loc.filename())).breakpoints.contains(loc) ||
+            returnVal != Runners.NO_RETURN
+        );
+
+        // TODO: FIXXXX
+        // if (error != null && !caught && StackData.frames(ctx).size() > 1) error = null;
+
+        if (error != null && (execptionType == CatchType.ALL || execptionType == CatchType.UNCAUGHT && !caught)) {
+            pauseException(ctx);
+        }
+        else if (isBreakpointable && locToBreakpoint.containsKey(loc)) {
+            var bp = locToBreakpoint.get(loc);
+            var ok = bp.condition == null ? true : Values.toBoolean(run(currFrame, bp.condition).result);
+            if (ok) pauseDebug(ctx, locToBreakpoint.get(loc));
+        }
+        else if (isBreakpointable && tmpBreakpts.remove(loc)) pauseDebug(ctx, null);
+        else if (instruction.type == Type.NOP && instruction.match("debug")) pauseDebug(ctx, null);
+
+        while (enabled) {
+            switch (state) {
+                case PAUSED_EXCEPTION:
+                case PAUSED_NORMAL: break;
+
+                case STEPPING_OUT:
+                case RESUMED: return false;
+                case STEPPING_IN:
+                    if (!prevLocation.equals(loc)) {
+                        if (isBreakpointable) pauseDebug(ctx, null);
+                        else if (returnVal != Runners.NO_RETURN) pauseDebug(ctx, null);
+                        else return false;
+                    }
+                    else return false;
+                    break;
+                case STEPPING_OVER:
+                    if (stepOutFrame.frame == frame.frame) {
+                        if (isBreakpointable && (
+                            !loc.filename().equals(prevLocation.filename()) ||
+                            loc.line() != prevLocation.line()
+                        )) pauseDebug(ctx, null);
+                        else return false;
+                    }
+                    else return false;
+                    break;
+            }
+            updateNotifier.await();
+        }
+
+        return false;
+    }
+    @Override public void onFramePop(Context ctx, CodeFrame frame) {
+        updateFrames(ctx);
+
+        try { idToFrame.remove(codeFrameToFrame.remove(frame).id); }
+        catch (NullPointerException e) { }
+
+        if (ctx.frames().size() == 0) resume(State.RESUMED);
+        else if (stepOutFrame != null && stepOutFrame.frame == frame &&
+            (state == State.STEPPING_OUT || state == State.STEPPING_IN || state == State.STEPPING_OVER)
+        ) {
+            // if (state == State.STEPPING_OVER) state = State.STEPPING_IN;
+            // else {
+                pauseDebug(ctx, null);
+                updateNotifier.await();
+            // }
+        }
+    }
+
+    @Override public void connect() {
+        if (!target.attachDebugger(this)) {
+            ws.send(new V8Error("A debugger is already attached to this engine."));
+        }
+    }
+    @Override public void disconnect() {
+        target.detachDebugger();
+        enabled = false;
+        updateNotifier.next();
+    }
+
+    public SimpleDebugger(WebSocket ws, Engine target) {
+        this.ws = ws;
+        this.target = target;
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/V8Error.java
+++ b/src/me/topchetoeu/jscript/engine/debug/V8Error.java
@@ -0,0 +1,19 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONMap;
+
+public class V8Error {
+    public final String message;
+
+    public V8Error(String message) {
+        this.message = message;
+    }
+
+    @Override
+    public String toString() {
+        return JSON.stringify(new JSONMap().set("error", new JSONMap()
+            .set("message", message)
+        ));
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/V8Event.java
+++ b/src/me/topchetoeu/jscript/engine/debug/V8Event.java
@@ -0,0 +1,22 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONMap;
+
+public class V8Event {
+    public final String name;
+    public final JSONMap params;
+
+    public V8Event(String name, JSONMap params) {
+        this.name = name;
+        this.params = params;
+    }
+
+    @Override
+    public String toString() {
+        return JSON.stringify(new JSONMap()
+            .set("method", name)
+            .set("params", params)
+        );
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/V8Message.java
+++ b/src/me/topchetoeu/jscript/engine/debug/V8Message.java
@@ -0,0 +1,50 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.util.Map;
+
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONElement;
+import me.topchetoeu.jscript.json.JSONMap;
+
+public class V8Message {
+    public final String name;
+    public final int id;
+    public final JSONMap params;
+
+    public V8Message(String name, int id, Map<String, JSONElement> params) {
+        this.name = name;
+        this.params = new JSONMap(params);
+        this.id = id;
+    }
+    public V8Result respond(JSONMap result) {
+        return new V8Result(id, result);
+    }
+    public V8Result respond() {
+        return new V8Result(id, new JSONMap());
+    }
+
+    public V8Message(JSONMap raw) {
+        if (!raw.isNumber("id")) throw new IllegalArgumentException("Expected number property 'id'.");
+        if (!raw.isString("method")) throw new IllegalArgumentException("Expected string property 'method'.");
+
+        this.name = raw.string("method");
+        this.id = (int)raw.number("id");
+        this.params = raw.contains("params") ? raw.map("params") : new JSONMap();
+    }
+    public V8Message(String raw) {
+        this(JSON.parse(null, raw).map());
+    }
+
+    public JSONMap toMap() {
+        var res = new JSONMap();
+        return res;
+    }
+    @Override
+    public String toString() {
+        return JSON.stringify(new JSONMap()
+            .set("method", name)
+            .set("params", params)
+            .set("id", id)
+        );
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/V8Result.java
+++ b/src/me/topchetoeu/jscript/engine/debug/V8Result.java
@@ -0,0 +1,22 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import me.topchetoeu.jscript.json.JSON;
+import me.topchetoeu.jscript.json.JSONMap;
+
+public class V8Result {
+    public final int id;
+    public final JSONMap result;
+
+    public V8Result(int id, JSONMap result) {
+        this.id = id;
+        this.result = result;
+    }
+
+    @Override
+    public String toString() {
+        return JSON.stringify(new JSONMap()
+            .set("id", id)
+            .set("result", result)
+        );
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/WebSocket.java
+++ b/src/me/topchetoeu/jscript/engine/debug/WebSocket.java
@@ -0,0 +1,216 @@
+package me.topchetoeu.jscript.engine.debug;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+
+import me.topchetoeu.jscript.engine.debug.WebSocketMessage.Type;
+import me.topchetoeu.jscript.exceptions.UncheckedIOException;
+
+public class WebSocket implements AutoCloseable {
+    public long maxLength = 1 << 20;
+
+    private Socket socket;
+    private boolean closed = false;
+
+    private OutputStream out() {
+        try { return socket.getOutputStream(); }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+    private InputStream in() {
+        try { return socket.getInputStream(); }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+
+    private long readLen(int byteLen) {
+        long res = 0;
+
+        try {
+            if (byteLen == 126) {
+                res |= in().read() << 8;
+                res |= in().read();
+                return res;
+            }
+            else if (byteLen == 127) {
+                res |= in().read() << 56;
+                res |= in().read() << 48;
+                res |= in().read() << 40;
+                res |= in().read() << 32;
+                res |= in().read() << 24;
+                res |= in().read() << 16;
+                res |= in().read() << 8;
+                res |= in().read();
+                return res;
+            }
+            else return byteLen;
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+    private byte[] readMask(boolean has) {
+        if (has) {
+            try { return new byte[] {
+                (byte)in().read(),
+                (byte)in().read(),
+                (byte)in().read(),
+                (byte)in().read()
+            }; }
+            catch (IOException e) { throw new UncheckedIOException(e); }
+        }
+        else return new byte[4];
+    }
+
+    private void writeLength(int len) {
+        try {
+            if (len < 126) {
+                out().write((int)len);
+            }
+            else if (len <= 0xFFFF) {
+                out().write(126);
+                out().write((int)(len >> 8) & 0xFF);
+                out().write((int)len & 0xFF);
+            }
+            else {
+                out().write(127);
+                out().write((len >> 56) & 0xFF);
+                out().write((len >> 48) & 0xFF);
+                out().write((len >> 40) & 0xFF);
+                out().write((len >> 32) & 0xFF);
+                out().write((len >> 24) & 0xFF);
+                out().write((len >> 16) & 0xFF);
+                out().write((len >> 8) & 0xFF);
+                out().write(len & 0xFF);
+            }
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+    private synchronized void write(int type, byte[] data) {
+        try {
+            int i;
+
+            for (i = 0; i < data.length / 0xFFFF; i++) {
+                out().write(type);
+                writeLength(0xFFFF);
+                out().write(data, i * 0xFFFF, 0xFFFF);
+                type = 0;
+            }
+
+            out().write(type | 0x80);
+            writeLength(data.length % 0xFFFF);
+            out().write(data, i * 0xFFFF, data.length % 0xFFFF);
+        }
+        catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    public void send(String data) {
+        if (closed) throw new IllegalStateException("Object is closed.");
+        write(1, data.getBytes());
+    }
+    public void send(byte[] data) {
+        if (closed) throw new IllegalStateException("Object is closed.");
+        write(2, data);
+    }
+    public void send(WebSocketMessage msg) {
+        if (msg.type == Type.Binary) send(msg.binaryData());
+        else send(msg.textData());
+    }
+    public void send(Object data) {
+        if (closed) throw new IllegalStateException("Object is closed.");
+        write(1, data.toString().getBytes());
+    }
+
+    public void close(String reason) {
+        if (socket != null) {
+            try {
+                write(8, reason.getBytes());
+                socket.close();
+            }
+            catch (Throwable e) { }
+        }
+
+        socket = null;
+        closed = true;
+    }
+    public void close() {
+        close("");
+    }
+
+    private WebSocketMessage fail(String reason) {
+        System.out.println("WebSocket Error: " + reason);
+        close(reason);
+        return null;
+    }
+
+    private byte[] readData() {
+        try {
+            var maskLen = in().read();
+            var hasMask = (maskLen & 0x80) != 0;
+            var len = (int)readLen(maskLen & 0x7F);
+            var mask = readMask(hasMask);
+    
+            if (len > maxLength) fail("WebSocket Error: client exceeded configured max message size");
+            else {
+                var buff = new byte[len];
+    
+                if (in().read(buff) < len) fail("WebSocket Error: payload too short");
+                else {
+                    for (int i = 0; i < len; i++) {
+                        buff[i] ^= mask[(int)(i % 4)];
+                    }
+                    return buff;
+                }
+            }
+
+            return null;
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+
+    public WebSocketMessage receive() {
+        try {
+            var data = new ByteArrayOutputStream();
+            var type = 0;
+
+            while (socket != null && !closed) {
+                var finId = in().read();
+                if (finId < 0) break;
+                var fin = (finId & 0x80) != 0;
+                int id = finId & 0x0F;
+
+                if (id == 0x8) { close(); return null; }
+                if (id >= 0x8) {
+                    if (!fin) return fail("WebSocket Error: client-sent control frame was fragmented");
+                    if (id == 0x9) write(0xA, data.toByteArray());
+                    continue;
+                }
+
+                if (type == 0) type = id;
+                if (type == 0) return fail("WebSocket Error: client used opcode 0x00 for first fragment");
+
+                var buff = readData();
+                if (buff == null) break;
+
+                if (data.size() + buff.length > maxLength) return fail("WebSocket Error: client exceeded configured max message size");
+                data.write(buff);
+
+                if (!fin) continue;
+                var raw = data.toByteArray();
+
+                if (type == 1) return new WebSocketMessage(new String(raw));
+                else return new WebSocketMessage(raw);
+            }
+        }
+        catch (IOException e) {
+            close();
+        }
+
+        return null;
+    }
+
+    public WebSocket(Socket socket) {
+        this.socket = socket;
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/debug/WebSocketMessage.java
+++ b/src/me/topchetoeu/jscript/engine/debug/WebSocketMessage.java
@@ -0,0 +1,29 @@
+package me.topchetoeu.jscript.engine.debug;
+
+public class WebSocketMessage {
+    public static enum Type {
+        Text,
+        Binary,
+    }
+
+    public final Type type;
+    private final Object data;
+
+    public final String textData() {
+        if (type != Type.Text) throw new IllegalStateException("Message is not text.");
+        return (String)data;
+    }
+    public final byte[] binaryData() {
+        if (type != Type.Binary) throw new IllegalStateException("Message is not binary.");
+        return (byte[])data;
+    }
+
+    public WebSocketMessage(String data) {
+        this.type = Type.Text;
+        this.data = data;
+    }
+    public WebSocketMessage(byte[] data) {
+        this.type = Type.Binary;
+        this.data = data;
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/frame/CodeFrame.java
+++ b/src/me/topchetoeu/jscript/engine/frame/CodeFrame.java
@@ -1,19 +1,23 @@
 package me.topchetoeu.jscript.engine.frame;

+import java.util.List;
 import java.util.Stack;

 import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.Context;
 import me.topchetoeu.jscript.engine.scope.LocalScope;
 import me.topchetoeu.jscript.engine.scope.ValueVariable;
 import me.topchetoeu.jscript.engine.values.ArrayValue;
 import me.topchetoeu.jscript.engine.values.CodeFunction;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.engine.values.ScopeValue;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.exceptions.InterruptException;

 public class CodeFrame {
-    private class TryCtx {
+    public static class TryCtx {
        public static final int STATE_TRY = 0;
        public static final int STATE_CATCH = 1;
        public static final int STATE_FINALLY_THREW = 2;
@@ -54,8 +58,56 @@ public class CodeFrame {
    public boolean jumpFlag = false;
    private Location prevLoc = null;

+    public ObjectValue getLocalScope(Context ctx, boolean props) {
+        var names = new String[scope.locals.length];
+
+        for (int i = 0; i < scope.locals.length; i++) {
+            var name = "local_" + (i - 2);
+
+            if (i == 0) name = "this";
+            else if (i == 1) name = "arguments";
+            else if (i < function.localNames.length) name = function.localNames[i];
+
+            names[i] = name;
+        }
+
+        return new ScopeValue(scope.locals, names);
+    }
+    public ObjectValue getCaptureScope(Context ctx, boolean props) {
+        var names = new String[scope.captures.length];
+
+        for (int i = 0; i < scope.captures.length; i++) {
+            var name = "capture_" + (i - 2);
+            if (i < function.captureNames.length) name = function.captureNames[i];
+            names[i] = name;
+        }
+
+        return new ScopeValue(scope.captures, names);
+    }
+    public ObjectValue getValStackScope(Context ctx) {
+        return new ObjectValue() {
+            @Override
+            protected Object getField(Context ctx, Object key) {
+                var i = (int)Values.toNumber(ctx, key);
+                if (i < 0 || i >= stackPtr) return null;
+                else return stack[i];
+            }
+            @Override
+            protected boolean hasField(Context ctx, Object key) {
+                return true;
+            }
+            @Override
+            public List<Object> keys(boolean includeNonEnumerable) {
+                var res = super.keys(includeNonEnumerable);
+                for (var i = 0; i < stackPtr; i++) res.add(i);
+                return res;
+            }
+        };
+    }
+
    public void addTry(int n, int catchN, int finallyN) {
        var res = new TryCtx(codePtr + 1, n, catchN, finallyN);
+        if (!tryStack.empty()) res.err = tryStack.peek().err;

        tryStack.add(res);
    }
@@ -93,35 +145,35 @@ public class CodeFrame {
        stack[stackPtr++] = Values.normalize(ctx, val);
    }

-    private void setCause(Context ctx, EngineException err, EngineException cause) throws InterruptedException {
-        if (err.value instanceof ObjectValue) {
-            Values.setMember(ctx, err, ctx.env.symbol("Symbol.cause"), cause);
-        }
-        err.cause = cause;
-    }
-    private Object nextNoTry(Context ctx) throws InterruptedException {
-        if (Thread.currentThread().isInterrupted()) throw new InterruptedException();
-        if (codePtr < 0 || codePtr >= function.body.length) return null;
-
-        var instr = function.body[codePtr];
-
-        var loc = instr.location;
-        if (loc != null) prevLoc = loc;
-
-        try {
-            this.jumpFlag = false;
-            return Runners.exec(ctx, instr, this);
-        }
-        catch (EngineException e) {
-            throw e.add(function.name, prevLoc).setContext(ctx);
-        }
+    private void setCause(Context ctx, EngineException err, EngineException cause) {
+        err.setCause(cause);
    }

-    public Object next(Context ctx, Object value, Object returnValue, EngineException error) throws InterruptedException {
+    public Object next(Context ctx, Object value, Object returnValue, EngineException error) {
        if (value != Runners.NO_RETURN) push(ctx, value);

+        Instruction instr = null;
+        if (codePtr >= 0 && codePtr < function.body.length) instr = function.body[codePtr];
+
        if (returnValue == Runners.NO_RETURN && error == null) {
-            try { returnValue = nextNoTry(ctx); }
+            try {
+                if (Thread.currentThread().isInterrupted()) throw new InterruptException();
+
+                if (instr == null) returnValue = null;
+                else {
+                    ctx.engine.onInstruction(ctx, this, instr, Runners.NO_RETURN, null, false);
+
+                    if (instr.location != null) prevLoc = instr.location;
+
+                    try {
+                        this.jumpFlag = false;
+                        returnValue = Runners.exec(ctx, instr, this);
+                    }
+                    catch (EngineException e) {
+                        error = e.add(function.name, prevLoc).setCtx(function.environment, ctx.engine);
+                    }
+                }
+            }
            catch (EngineException e) { error = e; }
        }

@@ -144,7 +196,7 @@ public class CodeFrame {
                    }
                    else if (returnValue != Runners.NO_RETURN) {
                        if (tryCtx.hasFinally) {
-                            tryCtx.retVal = error;
+                            tryCtx.retVal = returnValue;
                            newState = TryCtx.STATE_FINALLY_RETURNED;
                        }
                        break;
@@ -160,6 +212,7 @@ public class CodeFrame {
                    break;
                case TryCtx.STATE_CATCH:
                    if (error != null) {
+                        setCause(ctx, error, tryCtx.err);
                        if (tryCtx.hasFinally) {
                            tryCtx.err = error;
                            newState = TryCtx.STATE_FINALLY_THREW;
@@ -185,27 +238,31 @@ public class CodeFrame {
                case TryCtx.STATE_FINALLY_THREW:
                    if (error != null) setCause(ctx, error, tryCtx.err);
                    else if (codePtr < tryCtx.finallyStart || codePtr >= tryCtx.end) error = tryCtx.err;
-                    else return Runners.NO_RETURN;
+                    else if (returnValue == Runners.NO_RETURN) return Runners.NO_RETURN;
                    break;
                case TryCtx.STATE_FINALLY_RETURNED:
+                    if (error != null) setCause(ctx, error, tryCtx.err);
                    if (returnValue == Runners.NO_RETURN) {
                        if (codePtr < tryCtx.finallyStart || codePtr >= tryCtx.end) returnValue = tryCtx.retVal;
                        else return Runners.NO_RETURN;
                    }
                    break;
                case TryCtx.STATE_FINALLY_JUMPED:
-                    if (codePtr < tryCtx.finallyStart || codePtr >= tryCtx.end) {
+                    if (error != null) setCause(ctx, error, tryCtx.err);
+                    else if (codePtr < tryCtx.finallyStart || codePtr >= tryCtx.end) {
                        if (!jumpFlag) codePtr = tryCtx.jumpPtr;
                        else codePtr = tryCtx.end;
                    }
-                    else return Runners.NO_RETURN;
+                    else if (returnValue == Runners.NO_RETURN) return Runners.NO_RETURN;
                    break;
            }

            if (tryCtx.state == TryCtx.STATE_CATCH) scope.catchVars.remove(scope.catchVars.size() - 1);

            if (newState == -1) {
+                var err = tryCtx.err;
                tryStack.pop();
+                if (!tryStack.isEmpty()) tryStack.peek().err = err;
                continue;
            }

@@ -214,6 +271,7 @@ public class CodeFrame {
                case TryCtx.STATE_CATCH:
                    scope.catchVars.add(new ValueVariable(false, tryCtx.err.value));
                    codePtr = tryCtx.catchStart;
+                    ctx.engine.onInstruction(ctx, this, function.body[codePtr], null, error, true);
                    break;
                default:
                    codePtr = tryCtx.finallyStart;
@@ -221,23 +279,17 @@ public class CodeFrame {

            return Runners.NO_RETURN;
        }
-    
-        if (error != null) throw error.setContext(ctx);
-        if (returnValue != Runners.NO_RETURN) return returnValue;
-        return Runners.NO_RETURN;
-    }

-    public Object run(Context ctx) throws InterruptedException {
-        try {
-            ctx.message.pushFrame(ctx, this);
-            while (true) {
-                var res = next(ctx, Runners.NO_RETURN, Runners.NO_RETURN, null);
-                if (res != Runners.NO_RETURN) return res;
-            }
+        if (error != null) {
+            ctx.engine.onInstruction(ctx, this, instr, null, error, false);
+            throw error;
        }
-        finally {
-            ctx.message.popFrame(this);
+        if (returnValue != Runners.NO_RETURN) {
+            ctx.engine.onInstruction(ctx, this, instr, returnValue, null, false);
+            return returnValue;
        }
+
+        return Runners.NO_RETURN;
    }

    public CodeFrame(Context ctx, Object thisArg, Object[] args, CodeFunction func) {
--- a/src/me/topchetoeu/jscript/engine/frame/Runners.java
+++ b/src/me/topchetoeu/jscript/engine/frame/Runners.java
@@ -4,6 +4,7 @@ import java.util.Collections;

 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.Engine;
 import me.topchetoeu.jscript.engine.Operation;
 import me.topchetoeu.jscript.engine.scope.ValueVariable;
 import me.topchetoeu.jscript.engine.values.ArrayValue;
@@ -22,52 +23,37 @@ public class Runners {
    public static Object execThrow(Context ctx, Instruction instr, CodeFrame frame) {
        throw new EngineException(frame.pop());
    }
-    public static Object execThrowSyntax(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execThrowSyntax(Context ctx, Instruction instr, CodeFrame frame) {
        throw EngineException.ofSyntax((String)instr.get(0));
    }

-    private static Object call(Context ctx, Object func, Object thisArg, Object ...args) throws InterruptedException {
-        return Values.call(ctx, func, thisArg, args);
-    }
-
-    public static Object execCall(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execCall(Context ctx, Instruction instr, CodeFrame frame) {
        var callArgs = frame.take(instr.get(0));
        var func = frame.pop();
        var thisArg = frame.pop();

-        frame.push(ctx, call(ctx, func, thisArg, callArgs));
+        frame.push(ctx, Values.call(ctx, func, thisArg, callArgs));

        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execCallNew(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execCallNew(Context ctx, Instruction instr, CodeFrame frame) {
        var callArgs = frame.take(instr.get(0));
        var funcObj = frame.pop();

        frame.push(ctx, Values.callNew(ctx, funcObj, callArgs));

-        // if (Values.isFunction(funcObj) && Values.function(funcObj).special) {
-        //     frame.push(ctx, call(ctx, funcObj, null, callArgs));
-        // }
-        // else {
-        //     var proto = Values.getMember(ctx, funcObj, "prototype");
-        //     var obj = new ObjectValue();
-        //     obj.setPrototype(ctx, proto);
-        //     call(ctx, funcObj, obj, callArgs);
-        //     frame.push(ctx, obj);
-        // }
-
        frame.codePtr++;
        return NO_RETURN;
    }

-    public static Object execMakeVar(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execMakeVar(Context ctx, Instruction instr, CodeFrame frame) {
        var name = (String)instr.get(0);
-        ctx.env.global.define(name);
+        ctx.environment().global.define(name);
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execDefProp(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execDefProp(Context ctx, Instruction instr, CodeFrame frame) {
        var setter = frame.pop();
        var getter = frame.pop();
        var name = frame.pop();
@@ -82,7 +68,7 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execInstanceof(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execInstanceof(Context ctx, Instruction instr, CodeFrame frame) {
        var type = frame.pop();
        var obj = frame.pop();

@@ -97,27 +83,37 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execKeys(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execKeys(Context ctx, Instruction instr, CodeFrame frame) {
        var val = frame.pop();

-        var arr = new ObjectValue();
-        var i = 0;
-
        var members = Values.getMembers(ctx, val, false, false);
        Collections.reverse(members);
+
+        frame.push(ctx, null);
+
        for (var el : members) {
            if (el instanceof Symbol) continue;
-            arr.defineProperty(ctx, i++, el);
+            var obj = new ObjectValue();
+            obj.defineProperty(ctx, "value", el);
+            frame.push(ctx, obj);
        }
+        // var arr = new ObjectValue();

-        arr.defineProperty(ctx, "length", i);
+        // var members = Values.getMembers(ctx, val, false, false);
+        // Collections.reverse(members);
+        // for (var el : members) {
+        //     if (el instanceof Symbol) continue;
+        //     arr.defineProperty(ctx, i++, el);
+        // }

-        frame.push(ctx, arr);
+        // arr.defineProperty(ctx, "length", i);
+
+        // frame.push(ctx, arr);
        frame.codePtr++;
        return NO_RETURN;
    }

-    public static Object execTry(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execTry(Context ctx, Instruction instr, CodeFrame frame) {
        frame.addTry(instr.get(0), instr.get(1), instr.get(2));
        frame.codePtr++;
        return NO_RETURN;
@@ -155,10 +151,10 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execLoadVar(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execLoadVar(Context ctx, Instruction instr, CodeFrame frame) {
        var i = instr.get(0);

-        if (i instanceof String) frame.push(ctx, ctx.env.global.get(ctx, (String)i));
+        if (i instanceof String) frame.push(ctx, ctx.environment().global.get(ctx, (String)i));
        else frame.push(ctx, frame.scope.get((int)i).get(ctx));

        frame.codePtr++;
@@ -170,7 +166,7 @@ public class Runners {
        return NO_RETURN;
    }
    public static Object execLoadGlob(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, ctx.env.global.obj);
+        frame.push(ctx, ctx.environment().global.obj);
        frame.codePtr++;
        return NO_RETURN;
    }
@@ -191,15 +187,15 @@ public class Runners {
            captures[i - 3] = frame.scope.get(instr.get(i));
        }

-        var body = ctx.message.engine.functions.get(id);
-        var func = new CodeFunction(ctx.env, "", localsN, len, captures, body);
+        var body = Engine.functions.get(id);
+        var func = new CodeFunction(ctx.environment(), "", localsN, len, captures, body);

        frame.push(ctx, func);

        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execLoadMember(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execLoadMember(Context ctx, Instruction instr, CodeFrame frame) {
        var key = frame.pop();
        var obj = frame.pop();

@@ -212,12 +208,12 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execLoadKeyMember(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execLoadKeyMember(Context ctx, Instruction instr, CodeFrame frame) {
        frame.push(ctx, instr.get(0));
        return execLoadMember(ctx, instr, frame);
    }
-    public static Object execLoadRegEx(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
-        frame.push(ctx, ctx.env.regexConstructor.call(ctx, null, instr.get(0), instr.get(1)));
+    public static Object execLoadRegEx(Context ctx, Instruction instr, CodeFrame frame) {
+        frame.push(ctx, ctx.environment().regexConstructor.call(ctx, null, instr.get(0), instr.get(1)));
        frame.codePtr++;
        return NO_RETURN;
    }
@@ -227,7 +223,7 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execStoreMember(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execStoreMember(Context ctx, Instruction instr, CodeFrame frame) {
        var val = frame.pop();
        var key = frame.pop();
        var obj = frame.pop();
@@ -237,11 +233,11 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execStoreVar(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execStoreVar(Context ctx, Instruction instr, CodeFrame frame) {
        var val = (boolean)instr.get(1) ? frame.peek() : frame.pop();
        var i = instr.get(0);

-        if (i instanceof String) ctx.env.global.set(ctx, (String)i, val);
+        if (i instanceof String) ctx.environment().global.set(ctx, (String)i, val);
        else frame.scope.get((int)i).set(ctx, val);

        frame.codePtr++;
@@ -258,7 +254,7 @@ public class Runners {
        frame.jumpFlag = true;
        return NO_RETURN;
    }
-    public static Object execJmpIf(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execJmpIf(Context ctx, Instruction instr, CodeFrame frame) {
        if (Values.toBoolean(frame.pop())) {
            frame.codePtr += (int)instr.get(0);
            frame.jumpFlag = true;
@@ -266,7 +262,7 @@ public class Runners {
        else frame.codePtr ++;
        return NO_RETURN;
    }
-    public static Object execJmpIfNot(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execJmpIfNot(Context ctx, Instruction instr, CodeFrame frame) {
        if (Values.not(frame.pop())) {
            frame.codePtr += (int)instr.get(0);
            frame.jumpFlag = true;
@@ -275,7 +271,7 @@ public class Runners {
        return NO_RETURN;
    }

-    public static Object execIn(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execIn(Context ctx, Instruction instr, CodeFrame frame) {
        var obj = frame.pop();
        var index = frame.pop();

@@ -283,13 +279,13 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execTypeof(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execTypeof(Context ctx, Instruction instr, CodeFrame frame) {
        String name = instr.get(0);
        Object obj;

        if (name != null) {
-            if (ctx.env.global.has(ctx, name)) {
-                obj = ctx.env.global.get(ctx, name);
+            if (ctx.environment().global.has(ctx, name)) {
+                obj = ctx.environment().global.get(ctx, name);
            }
            else obj = null;
        }
@@ -300,21 +296,12 @@ public class Runners {
        frame.codePtr++;
        return NO_RETURN;
    }
-    public static Object execNop(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
-        if (instr.is(0, "dbg_names")) {
-            var names = new String[instr.params.length - 1];
-            for (var i = 0; i < instr.params.length - 1; i++) {
-                if (!(instr.params[i + 1] instanceof String)) throw EngineException.ofSyntax("NOP dbg_names instruction must specify only string parameters.");
-                names[i] = (String)instr.params[i + 1];
-            }
-            frame.scope.setNames(names);
-        }
-
+    public static Object execNop(Context ctx, Instruction instr, CodeFrame frame) {
        frame.codePtr++;
        return NO_RETURN;
    }

-    public static Object execDelete(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execDelete(Context ctx, Instruction instr, CodeFrame frame) {
        var key = frame.pop();
        var val = frame.pop();

@@ -324,7 +311,7 @@ public class Runners {
        return NO_RETURN;
    }

-    public static Object execOperation(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object execOperation(Context ctx, Instruction instr, CodeFrame frame) {
        Operation op = instr.get(0);
        var args = new Object[op.operands];

@@ -335,7 +322,7 @@ public class Runners {
        return NO_RETURN;
    }

-    public static Object exec(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
+    public static Object exec(Context ctx, Instruction instr, CodeFrame frame) {
        switch (instr.type) {
            case NOP: return execNop(ctx, instr, frame);
            case RETURN: return execReturn(ctx, instr, frame);
--- a/src/me/topchetoeu/jscript/engine/scope/GlobalScope.java
+++ b/src/me/topchetoeu/jscript/engine/scope/GlobalScope.java
@@ -15,7 +15,7 @@ public class GlobalScope implements ScopeRecord {
    @Override
    public GlobalScope parent() { return null; }

-    public boolean has(Context ctx, String name) throws InterruptedException {
+    public boolean has(Context ctx, String name) {
        return obj.hasMember(ctx, name, false);
    }
    public Object getKey(String name) {
@@ -32,13 +32,7 @@ public class GlobalScope implements ScopeRecord {
    }

    public Object define(String name) {
-        try {
-            if (obj.hasMember(null, name, true)) return name;
-        }
-        catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-            return name;
-        }
+        if (obj.hasMember(null, name, true)) return name;
        obj.defineProperty(null, name, null);
        return name;
    }
@@ -59,11 +53,11 @@ public class GlobalScope implements ScopeRecord {
        define(null, val.name, readonly, val);
    }

-    public Object get(Context ctx, String name) throws InterruptedException {
+    public Object get(Context ctx, String name) {
        if (!obj.hasMember(ctx, name, false)) throw EngineException.ofSyntax("The variable '" + name + "' doesn't exist.");
        else return obj.getMember(ctx, name);
    }
-    public void set(Context ctx, String name, Object val) throws InterruptedException {
+    public void set(Context ctx, String name, Object val) {
        if (!obj.hasMember(ctx, name, false)) throw EngineException.ofSyntax("The variable '" + name + "' doesn't exist.");
        if (!obj.setMember(ctx, name, val, false)) throw EngineException.ofSyntax("The global '" + name + "' is readonly.");
    }
--- a/src/me/topchetoeu/jscript/engine/scope/LocalScope.java
+++ b/src/me/topchetoeu/jscript/engine/scope/LocalScope.java
@@ -3,43 +3,21 @@ package me.topchetoeu.jscript.engine.scope;
 import java.util.ArrayList;

 public class LocalScope {
-    private String[] names;
    public final ValueVariable[] captures;
    public final ValueVariable[] locals;
    public final ArrayList<ValueVariable> catchVars = new ArrayList<>();

    public ValueVariable get(int i) {
-        if (i >= locals.length)
-            return catchVars.get(i - locals.length);
+        if (i >= locals.length) return catchVars.get(i - locals.length);
        if (i >= 0) return locals[i];
        else return captures[~i];
    }

-    public String[] getNames() {
-        var res = new String[locals.length];
-
-        for (var i = 0; i < locals.length; i++) {
-            if (names == null || i >= names.length) res[i] = "local_" + i;
-            else res[i] = names[i];
-        }
-
-        return res;
-    }
-    public void setNames(String[] names) {
-        this.names = names;
-    }

    public int size() {
        return captures.length + locals.length;
    }

-    public void toGlobal(GlobalScope global) {
-        var names = getNames();
-        for (var i = 0; i < names.length; i++) {
-            global.define(names[i], locals[i]);
-        }
-    }
-
    public LocalScope(int n, ValueVariable[] captures) {
        locals = new ValueVariable[n];
        this.captures = captures;
--- a/src/me/topchetoeu/jscript/engine/scope/LocalScopeRecord.java
+++ b/src/me/topchetoeu/jscript/engine/scope/LocalScopeRecord.java
@@ -11,6 +11,9 @@ public class LocalScopeRecord implements ScopeRecord {
    private final ArrayList<String> captures = new ArrayList<>();
    private final ArrayList<String> locals = new ArrayList<>();

+    public String[] captures() {
+        return captures.toArray(String[]::new);
+    }
    public String[] locals() {
        return locals.toArray(String[]::new);
    }
@@ -59,7 +62,7 @@ public class LocalScopeRecord implements ScopeRecord {

        return name;
    }
-    public boolean has(Context ctx, String name) throws InterruptedException {
+    public boolean has(Context ctx, String name) {
        return
            global.has(ctx, name) ||
            locals.contains(name) ||
--- a/src/me/topchetoeu/jscript/engine/scope/Variable.java
+++ b/src/me/topchetoeu/jscript/engine/scope/Variable.java
@@ -3,7 +3,7 @@ package me.topchetoeu.jscript.engine.scope;
 import me.topchetoeu.jscript.engine.Context;

 public interface Variable {
-    Object get(Context ctx) throws InterruptedException;
+    Object get(Context ctx);
    default boolean readonly() { return true; }
-    default void set(Context ctx, Object val) throws InterruptedException { }
+    default void set(Context ctx, Object val) { }
 }
--- a/src/me/topchetoeu/jscript/engine/values/ArrayValue.java
+++ b/src/me/topchetoeu/jscript/engine/values/ArrayValue.java
@@ -14,13 +14,14 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
    private Object[] values;
    private int size;

-    private void alloc(int index) {
-        if (index < values.length) return;
+    private Object[] alloc(int index) {
+        index++;
+        if (index < values.length) return values;
        if (index < values.length * 2) index = values.length * 2;

        var arr = new Object[index];
        System.arraycopy(values, 0, arr, 0, values.length);
-        values = arr;
+        return arr;
    }

    public int size() { return size; }
@@ -28,7 +29,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        if (val < 0) return false;
        if (size > val) shrink(size - val);
        else {
-            alloc(val);
+            values = alloc(val);
            size = val;
        }
        return true;
@@ -43,7 +44,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
    public void set(Context ctx, int i, Object val) {
        if (i < 0) return;

-        alloc(i);
+        values = alloc(i);

        val = Values.normalize(ctx, val);
        if (val == null) val = UNDEFINED;
@@ -51,7 +52,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        if (i >= size) size = i + 1;
    }
    public boolean has(int i) {
-        return i >= 0 && i < values.length && values[i] != null;
+        return i >= 0 && i < size && values[i] != null;
    }
    public void remove(int i) {
        if (i < 0 || i >= values.length) return;
@@ -84,8 +85,9 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
    public void copyTo(Context ctx, ArrayValue arr, int sourceStart, int destStart, int count) {
        // Iterate in reverse to reallocate at most once
        for (var i = count - 1; i >= 0; i--) {
-            if (i + sourceStart < 0 || i + sourceStart >= size) arr.set(ctx, i + destStart, null);
+            if (i + sourceStart < 0 || i + sourceStart >= size) arr.remove(i + destStart);
            if (values[i + sourceStart] == UNDEFINED) arr.set(ctx, i + destStart, null);
+            else if (values[i + sourceStart] == null) arr.remove(i + destStart);
            else arr.set(ctx, i + destStart, values[i + sourceStart]);
        }
    }
@@ -97,7 +99,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
    }

    public void move(int srcI, int dstI, int n) {
-        alloc(dstI + n);
+        values = alloc(dstI + n);

        System.arraycopy(values, srcI, values, dstI, n);

@@ -122,7 +124,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
    }

    @Override
-    protected Object getField(Context ctx, Object key) throws InterruptedException {
+    protected Object getField(Context ctx, Object key) {
        if (key instanceof Number) {
            var i = ((Number)key).doubleValue();
            if (i >= 0 && i - Math.floor(i) == 0) {
@@ -133,7 +135,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        return super.getField(ctx, key);
    }
    @Override
-    protected boolean setField(Context ctx, Object key, Object val) throws InterruptedException {
+    protected boolean setField(Context ctx, Object key, Object val) {
        if (key instanceof Number) {
            var i = Values.number(key);
            if (i >= 0 && i - Math.floor(i) == 0) {
@@ -145,7 +147,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        return super.setField(ctx, key, val);
    }
    @Override
-    protected boolean hasField(Context ctx, Object key) throws InterruptedException {
+    protected boolean hasField(Context ctx, Object key) {
        if (key instanceof Number) {
            var i = Values.number(key);
            if (i >= 0 && i - Math.floor(i) == 0) {
@@ -156,7 +158,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        return super.hasField(ctx, key);
    }
    @Override
-    protected void deleteField(Context ctx, Object key) throws InterruptedException {
+    protected void deleteField(Context ctx, Object key) {
        if (key instanceof Number) {
            var i = Values.number(key);
            if (i >= 0 && i - Math.floor(i) == 0) {
@@ -212,7 +214,7 @@ public class ArrayValue extends ObjectValue implements Iterable<Object> {
        for (var i = 0; i < size; i++) this.values[i] = Values.normalize(ctx, values[i]);
    }

-    public static ArrayValue of(Context ctx, Collection<Object> values) {
+    public static ArrayValue of(Context ctx, Collection<?> values) {
        return new ArrayValue(ctx, values.toArray(Object[]::new));
    }
 }
--- a/src/me/topchetoeu/jscript/engine/values/CodeFunction.java
+++ b/src/me/topchetoeu/jscript/engine/values/CodeFunction.java
@@ -1,16 +1,19 @@
 package me.topchetoeu.jscript.engine.values;

 import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.Context;
 import me.topchetoeu.jscript.engine.Environment;
 import me.topchetoeu.jscript.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.engine.frame.Runners;
 import me.topchetoeu.jscript.engine.scope.ValueVariable;

 public class CodeFunction extends FunctionValue {
    public final int localsN;
    public final int length;
    public final Instruction[] body;
+    public final String[] captureNames, localNames;
    public final ValueVariable[] captures;
    public Environment environment;

@@ -28,16 +31,29 @@ public class CodeFunction extends FunctionValue {
    }

    @Override
-    public Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
-        return new CodeFrame(ctx, thisArg, args, this).run(ctx.setEnv(environment));
+    public Object call(Context ctx, Object thisArg, Object ...args) {
+        var frame = new CodeFrame(ctx, thisArg, args, this);
+        try {
+            ctx.pushFrame(frame);
+
+            while (true) {
+                var res = frame.next(ctx, Runners.NO_RETURN, Runners.NO_RETURN, null);
+                if (res != Runners.NO_RETURN) return res;
+            }
+        }
+        finally {
+            ctx.popFrame(frame);
+        }
    }

-    public CodeFunction(Environment environment, String name, int localsN, int length, ValueVariable[] captures, Instruction[] body) {
+    public CodeFunction(Environment environment, String name, int localsN, int length, ValueVariable[] captures, FunctionBody body) {
        super(name, length);
        this.captures = captures;
+        this.captureNames = body.captureNames;
+        this.localNames = body.localNames;
        this.environment = environment;
        this.localsN = localsN;
        this.length = length;
-        this.body = body;
+        this.body = body.instructions;
    }
 }
--- a/src/me/topchetoeu/jscript/engine/values/FunctionValue.java
+++ b/src/me/topchetoeu/jscript/engine/values/FunctionValue.java
@@ -11,31 +11,31 @@ public abstract class FunctionValue extends ObjectValue {

    @Override
    public String toString() {
-        return "function(...) {  ...}";
+        return String.format("function %s(...)", name);
    }

-    public abstract Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException;
-    public Object call(Context ctx) throws InterruptedException {
+    public abstract Object call(Context ctx, Object thisArg, Object ...args);
+    public Object call(Context ctx) {
        return call(ctx, null);
    }

    @Override
-    protected Object getField(Context ctx, Object key) throws InterruptedException {
-        if (key.equals("name")) return name;
-        if (key.equals("length")) return length;
+    protected Object getField(Context ctx, Object key) {
+        if ("name".equals(key)) return name;
+        if ("length".equals(key)) return length;
        return super.getField(ctx, key);
    }
    @Override
-    protected boolean setField(Context ctx, Object key, Object val) throws InterruptedException {
-        if (key.equals("name")) name = Values.toString(ctx, val);
-        else if (key.equals("length")) length = (int)Values.toNumber(ctx, val);
+    protected boolean setField(Context ctx, Object key, Object val) {
+        if ("name".equals(key)) name = Values.toString(ctx, val);
+        else if ("length".equals(key)) length = (int)Values.toNumber(ctx, val);
        else return super.setField(ctx, key, val);
        return true;
    }
    @Override
-    protected boolean hasField(Context ctx, Object key) throws InterruptedException {
-        if (key.equals("name")) return true;
-        if (key.equals("length")) return true;
+    protected boolean hasField(Context ctx, Object key) {
+        if ("name".equals(key)) return true;
+        if ("length".equals(key)) return true;
        return super.hasField(ctx, key);
    }

--- a/src/me/topchetoeu/jscript/engine/values/NativeFunction.java
+++ b/src/me/topchetoeu/jscript/engine/values/NativeFunction.java
@@ -4,13 +4,13 @@ import me.topchetoeu.jscript.engine.Context;

 public class NativeFunction extends FunctionValue {
    public static interface NativeFunctionRunner {
-        Object run(Context ctx, Object thisArg, Object[] args) throws InterruptedException;
+        Object run(Context ctx, Object thisArg, Object[] args);
    }

    public final NativeFunctionRunner action;

    @Override
-    public Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
+    public Object call(Context ctx, Object thisArg, Object ...args) {
        return action.run(ctx, thisArg, args);
    }

--- a/src/me/topchetoeu/jscript/engine/values/NativeWrapper.java
+++ b/src/me/topchetoeu/jscript/engine/values/NativeWrapper.java
@@ -7,12 +7,24 @@ public class NativeWrapper extends ObjectValue {
    public final Object wrapped;

    @Override
-    public ObjectValue getPrototype(Context ctx) throws InterruptedException {
-        if (prototype == NATIVE_PROTO)
-            return ctx.env.wrappersProvider.getProto(wrapped.getClass());
+    public ObjectValue getPrototype(Context ctx) {
+        if (prototype == NATIVE_PROTO) return ctx.environment().wrappers.getProto(wrapped.getClass());
        else return super.getPrototype(ctx);
    }

+    @Override
+    public String toString() {
+        return wrapped.toString();
+    }
+    @Override
+    public boolean equals(Object obj) {
+        return wrapped.equals(obj);
+    }
+    @Override
+    public int hashCode() {
+        return wrapped.hashCode();
+    }
+
    public NativeWrapper(Object wrapped) {
        this.wrapped = wrapped;
        prototype = NATIVE_PROTO;
--- a/src/me/topchetoeu/jscript/engine/values/ObjectValue.java
+++ b/src/me/topchetoeu/jscript/engine/values/ObjectValue.java
@@ -1,8 +1,8 @@
 package me.topchetoeu.jscript.engine.values;

 import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;

@@ -47,11 +47,11 @@ public class ObjectValue {
    protected Object prototype;

    public State state = State.NORMAL;
-    public HashMap<Object, Object> values = new HashMap<>();
-    public HashMap<Object, Property> properties = new HashMap<>();
-    public HashSet<Object> nonWritableSet = new HashSet<>();
-    public HashSet<Object> nonConfigurableSet = new HashSet<>();
-    public HashSet<Object> nonEnumerableSet = new HashSet<>();
+    public LinkedHashMap<Object, Object> values = new LinkedHashMap<>();
+    public LinkedHashMap<Object, Property> properties = new LinkedHashMap<>();
+    public LinkedHashSet<Object> nonWritableSet = new LinkedHashSet<>();
+    public LinkedHashSet<Object> nonConfigurableSet = new LinkedHashSet<>();
+    public LinkedHashSet<Object> nonEnumerableSet = new LinkedHashSet<>();

    public final boolean memberWritable(Object key) {
        if (state == State.FROZEN) return false;
@@ -103,8 +103,7 @@ public class ObjectValue {
        ) return true;

        if (!extensible() && !values.containsKey(key) && !properties.containsKey(key)) return false;
-        if (!memberConfigurable(key))
-            return false;
+        if (!memberConfigurable(key)) return false;

        nonWritableSet.remove(key);
        nonEnumerableSet.remove(key);
@@ -145,19 +144,17 @@ public class ObjectValue {
        return true;
    }

-    public ObjectValue getPrototype(Context ctx) throws InterruptedException {
+    public ObjectValue getPrototype(Context ctx) {
        try {
-            if (prototype == OBJ_PROTO) return ctx.env.proto("object");
-            if (prototype == ARR_PROTO) return ctx.env.proto("array");
-            if (prototype == FUNC_PROTO) return ctx.env.proto("function");
-            if (prototype == ERR_PROTO) return ctx.env.proto("error");
-            if (prototype == RANGE_ERR_PROTO) return ctx.env.proto("rangeErr");
-            if (prototype == SYNTAX_ERR_PROTO) return ctx.env.proto("syntaxErr");
-            if (prototype == TYPE_ERR_PROTO) return ctx.env.proto("typeErr");
-        }
-        catch (NullPointerException e) {
-            return null;
+            if (prototype == OBJ_PROTO) return ctx.environment().proto("object");
+            if (prototype == ARR_PROTO) return ctx.environment().proto("array");
+            if (prototype == FUNC_PROTO) return ctx.environment().proto("function");
+            if (prototype == ERR_PROTO) return ctx.environment().proto("error");
+            if (prototype == RANGE_ERR_PROTO) return ctx.environment().proto("rangeErr");
+            if (prototype == SYNTAX_ERR_PROTO) return ctx.environment().proto("syntaxErr");
+            if (prototype == TYPE_ERR_PROTO) return ctx.environment().proto("typeErr");
        }
+        catch (NullPointerException e) { return null; }

        return (ObjectValue)prototype;
    }
@@ -172,14 +169,14 @@ public class ObjectValue {
        else if (Values.isObject(val)) {
            var obj = Values.object(val);

-            if (ctx != null && ctx.env != null) {
-                if (obj == ctx.env.proto("object")) prototype = OBJ_PROTO;
-                else if (obj == ctx.env.proto("array")) prototype = ARR_PROTO;
-                else if (obj == ctx.env.proto("function")) prototype = FUNC_PROTO;
-                else if (obj == ctx.env.proto("error")) prototype = ERR_PROTO;
-                else if (obj == ctx.env.proto("syntaxErr")) prototype = SYNTAX_ERR_PROTO;
-                else if (obj == ctx.env.proto("typeErr")) prototype = TYPE_ERR_PROTO;
-                else if (obj == ctx.env.proto("rangeErr")) prototype = RANGE_ERR_PROTO;
+            if (ctx != null && ctx.environment() != null) {
+                if (obj == ctx.environment().proto("object")) prototype = OBJ_PROTO;
+                else if (obj == ctx.environment().proto("array")) prototype = ARR_PROTO;
+                else if (obj == ctx.environment().proto("function")) prototype = FUNC_PROTO;
+                else if (obj == ctx.environment().proto("error")) prototype = ERR_PROTO;
+                else if (obj == ctx.environment().proto("syntaxErr")) prototype = SYNTAX_ERR_PROTO;
+                else if (obj == ctx.environment().proto("typeErr")) prototype = TYPE_ERR_PROTO;
+                else if (obj == ctx.environment().proto("rangeErr")) prototype = RANGE_ERR_PROTO;
                else prototype = obj;
            }
            else prototype = obj;
@@ -203,19 +200,19 @@ public class ObjectValue {
        return true;
    }

-    protected Property getProperty(Context ctx, Object key) throws InterruptedException {
+    protected Property getProperty(Context ctx, Object key) {
        if (properties.containsKey(key)) return properties.get(key);
        var proto = getPrototype(ctx);
        if (proto != null) return proto.getProperty(ctx, key);
        else return null;
    }
-    protected Object getField(Context ctx, Object key) throws InterruptedException {
+    protected Object getField(Context ctx, Object key) {
        if (values.containsKey(key)) return values.get(key);
        var proto = getPrototype(ctx);
        if (proto != null) return proto.getField(ctx, key);
        else return null;
    }
-    protected boolean setField(Context ctx, Object key, Object val) throws InterruptedException {
+    protected boolean setField(Context ctx, Object key, Object val) {
        if (val instanceof FunctionValue && ((FunctionValue)val).name.equals("")) {
            ((FunctionValue)val).name = Values.toString(ctx, key);
        }
@@ -223,14 +220,14 @@ public class ObjectValue {
        values.put(key, val);
        return true;
    }
-    protected void deleteField(Context ctx, Object key) throws InterruptedException {
+    protected void deleteField(Context ctx, Object key) {
        values.remove(key);
    }
-    protected boolean hasField(Context ctx, Object key) throws InterruptedException {
+    protected boolean hasField(Context ctx, Object key) {
        return values.containsKey(key);
    }

-    public final Object getMember(Context ctx, Object key, Object thisArg) throws InterruptedException {
+    public final Object getMember(Context ctx, Object key, Object thisArg) {
        key = Values.normalize(ctx, key);

        if ("__proto__".equals(key)) {
@@ -246,11 +243,11 @@ public class ObjectValue {
        }
        else return getField(ctx, key);
    }
-    public final Object getMember(Context ctx, Object key) throws InterruptedException {
+    public final Object getMember(Context ctx, Object key) {
        return getMember(ctx, key, this);
    }

-    public final boolean setMember(Context ctx, Object key, Object val, Object thisArg, boolean onlyProps) throws InterruptedException {
+    public final boolean setMember(Context ctx, Object key, Object val, Object thisArg, boolean onlyProps) {
        key = Values.normalize(ctx, key); val = Values.normalize(ctx, val);

        var prop = getProperty(ctx, key);
@@ -265,25 +262,25 @@ public class ObjectValue {
            values.put(key, val);
            return true;
        }
-        else if (key.equals("__proto__")) return setPrototype(ctx, val);
+        else if ("__proto__".equals(key)) return setPrototype(ctx, val);
        else if (nonWritableSet.contains(key)) return false;
        else return setField(ctx, key, val);
    }
-    public final boolean setMember(Context ctx, Object key, Object val, boolean onlyProps) throws InterruptedException {
+    public final boolean setMember(Context ctx, Object key, Object val, boolean onlyProps) {
        return setMember(ctx, Values.normalize(ctx, key), Values.normalize(ctx, val), this, onlyProps);
    }

-    public final boolean hasMember(Context ctx, Object key, boolean own) throws InterruptedException {
+    public final boolean hasMember(Context ctx, Object key, boolean own) {
        key = Values.normalize(ctx, key);

-        if (key != null && key.equals("__proto__")) return true;
+        if (key != null && "__proto__".equals(key)) return true;
        if (hasField(ctx, key)) return true;
        if (properties.containsKey(key)) return true;
        if (own) return false;
        var proto = getPrototype(ctx);
        return proto != null && proto.hasMember(ctx, key, own);
    }
-    public final boolean deleteMember(Context ctx, Object key) throws InterruptedException {
+    public final boolean deleteMember(Context ctx, Object key) {
        key = Values.normalize(ctx, key);

        if (!memberConfigurable(key)) return false;
@@ -294,7 +291,7 @@ public class ObjectValue {
        return true;
    }

-    public final ObjectValue getMemberDescriptor(Context ctx, Object key) throws InterruptedException {
+    public final ObjectValue getMemberDescriptor(Context ctx, Object key) {
        key = Values.normalize(ctx, key);

        var prop = properties.get(key);
--- a/src/me/topchetoeu/jscript/engine/values/ScopeValue.java
+++ b/src/me/topchetoeu/jscript/engine/values/ScopeValue.java
@@ -0,0 +1,51 @@
+package me.topchetoeu.jscript.engine.values;
+
+import java.util.HashMap;
+import java.util.List;
+
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.scope.ValueVariable;
+
+public class ScopeValue extends ObjectValue {
+    public final ValueVariable[] variables;
+    public final HashMap<String, Integer> names = new HashMap<>();
+
+    @Override
+    protected Object getField(Context ctx, Object key) {
+        if (names.containsKey(key)) return variables[names.get(key)].get(ctx);
+        return super.getField(ctx, key);
+    }
+    @Override
+    protected boolean setField(Context ctx, Object key, Object val) {
+        if (names.containsKey(key)) {
+            variables[names.get(key)].set(ctx, val);
+            return true;
+        }
+
+        return super.setField(ctx, key, val);
+    }
+    @Override
+    protected void deleteField(Context ctx, Object key) {
+        if (names.containsKey(key)) return;
+        super.deleteField(ctx, key);
+    }
+    @Override
+    protected boolean hasField(Context ctx, Object key) {
+        if (names.containsKey(key)) return true;
+        return super.hasField(ctx, key);
+    }
+    @Override
+    public List<Object> keys(boolean includeNonEnumerable) {
+        var res = super.keys(includeNonEnumerable);
+        res.addAll(names.keySet());
+        return res;
+    }
+
+    public ScopeValue(ValueVariable[] variables, String[] names) {
+        this.variables = variables;
+        for (var i = 0; i < names.length && i < variables.length; i++) {
+            this.names.put(names[i], i);
+            this.nonConfigurableSet.add(names[i]);
+        }
+    }
+}
--- a/src/me/topchetoeu/jscript/engine/values/Values.java
+++ b/src/me/topchetoeu/jscript/engine/values/Values.java
@@ -16,8 +16,28 @@ import me.topchetoeu.jscript.engine.frame.ConvertHint;
 import me.topchetoeu.jscript.exceptions.ConvertException;
 import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.exceptions.SyntaxException;
+import me.topchetoeu.jscript.exceptions.UncheckedException;
+import me.topchetoeu.jscript.lib.PromiseLib;

 public class Values {
+    public static enum CompareResult {
+        NOT_EQUAL,
+        EQUAL,
+        LESS,
+        GREATER;
+
+        public boolean less() { return this == LESS; }
+        public boolean greater() { return this == GREATER; }
+        public boolean lessOrEqual() { return this == LESS || this == EQUAL; }
+        public boolean greaterOrEqual() { return this == GREATER || this == EQUAL; }
+
+        public static CompareResult from(int cmp) {
+            if (cmp < 0) return LESS;
+            if (cmp > 0) return GREATER;
+            return EQUAL;
+        }
+    }
+
    public static final Object NULL = new Object();

    public static boolean isObject(Object val) { return val instanceof ObjectValue; }
@@ -67,7 +87,7 @@ public class Values {
        return "object";
    }

-    private static Object tryCallConvertFunc(Context ctx, Object obj, String name) throws InterruptedException {
+    private static Object tryCallConvertFunc(Context ctx, Object obj, String name) {
        var func = getMember(ctx, obj, name);

        if (func != null) {
@@ -88,7 +108,7 @@ public class Values {
            obj == NULL;
    }

-    public static Object toPrimitive(Context ctx, Object obj, ConvertHint hint) throws InterruptedException {
+    public static Object toPrimitive(Context ctx, Object obj, ConvertHint hint) {
        obj = normalize(ctx, obj);
        if (isPrimitive(obj)) return obj;

@@ -96,37 +116,32 @@ public class Values {
        var second = hint == ConvertHint.VALUEOF ? "toString" : "valueOf";

        if (ctx != null) {
-            try {
-                return tryCallConvertFunc(ctx, obj, first);
-            }
-            catch (EngineException unused) {
-                return tryCallConvertFunc(ctx, obj, second);
-            }
+            try { return tryCallConvertFunc(ctx, obj, first); }
+            catch (EngineException unused) { return tryCallConvertFunc(ctx, obj, second); }
        }

        throw EngineException.ofType("Value couldn't be converted to a primitive.");
    }
    public static boolean toBoolean(Object obj) {
        if (obj == NULL || obj == null) return false;
-        if (obj instanceof Number && number(obj) == 0) return false;
+        if (obj instanceof Number && (number(obj) == 0 || Double.isNaN(number(obj)))) return false;
        if (obj instanceof String && ((String)obj).equals("")) return false;
        if (obj instanceof Boolean) return (Boolean)obj;
        return true;
    }
-    public static double toNumber(Context ctx, Object obj) throws InterruptedException {
+    public static double toNumber(Context ctx, Object obj) {
        var val = toPrimitive(ctx, obj, ConvertHint.VALUEOF);

        if (val instanceof Number) return number(val);
        if (val instanceof Boolean) return ((Boolean)val) ? 1 : 0;
        if (val instanceof String) {
-            try {
-                return Double.parseDouble((String)val);
-            }
-            catch (NumberFormatException e) { }
+            try { return Double.parseDouble((String)val); }
+            catch (NumberFormatException e) { return Double.NaN; }
+            catch (Throwable e) { throw new UncheckedException(e); }
        }
        return Double.NaN;
    }
-    public static String toString(Context ctx, Object obj) throws InterruptedException {
+    public static String toString(Context ctx, Object obj) {
        var val = toPrimitive(ctx, obj, ConvertHint.VALUEOF);

        if (val == null) return "undefined";
@@ -141,52 +156,52 @@ public class Values {
        }
        if (val instanceof Boolean) return (Boolean)val ? "true" : "false";
        if (val instanceof String) return (String)val;
-        if (val instanceof Symbol) return ((Symbol)val).toString();
+        if (val instanceof Symbol) return val.toString();

        return "Unknown value";
    }

-    public static Object add(Context ctx, Object a, Object b) throws InterruptedException {
+    public static Object add(Context ctx, Object a, Object b) {
        if (a instanceof String || b instanceof String) return toString(ctx, a) + toString(ctx, b);
        else return toNumber(ctx, a) + toNumber(ctx, b);
    }
-    public static double subtract(Context ctx, Object a, Object b) throws InterruptedException {
+    public static double subtract(Context ctx, Object a, Object b) {
        return toNumber(ctx, a) - toNumber(ctx, b);
    }
-    public static double multiply(Context ctx, Object a, Object b) throws InterruptedException {
+    public static double multiply(Context ctx, Object a, Object b) {
        return toNumber(ctx, a) * toNumber(ctx, b);
    }
-    public static double divide(Context ctx, Object a, Object b) throws InterruptedException {
+    public static double divide(Context ctx, Object a, Object b) {
        return toNumber(ctx, a) / toNumber(ctx, b);
    }
-    public static double modulo(Context ctx, Object a, Object b) throws InterruptedException {
+    public static double modulo(Context ctx, Object a, Object b) {
        return toNumber(ctx, a) % toNumber(ctx, b);
    }
    
-    public static double negative(Context ctx, Object obj) throws InterruptedException {
+    public static double negative(Context ctx, Object obj) {
        return -toNumber(ctx, obj);
    }

-    public static int and(Context ctx, Object a, Object b) throws InterruptedException {
+    public static int and(Context ctx, Object a, Object b) {
        return (int)toNumber(ctx, a) & (int)toNumber(ctx, b);
    }
-    public static int or(Context ctx, Object a, Object b) throws InterruptedException {
+    public static int or(Context ctx, Object a, Object b) {
        return (int)toNumber(ctx, a) | (int)toNumber(ctx, b);
    }
-    public static int xor(Context ctx, Object a, Object b) throws InterruptedException {
+    public static int xor(Context ctx, Object a, Object b) {
        return (int)toNumber(ctx, a) ^ (int)toNumber(ctx, b);
    }
-    public static int bitwiseNot(Context ctx, Object obj) throws InterruptedException {
+    public static int bitwiseNot(Context ctx, Object obj) {
        return ~(int)toNumber(ctx, obj);
    }

-    public static int shiftLeft(Context ctx, Object a, Object b) throws InterruptedException {
+    public static int shiftLeft(Context ctx, Object a, Object b) {
        return (int)toNumber(ctx, a) << (int)toNumber(ctx, b);
    }
-    public static int shiftRight(Context ctx, Object a, Object b) throws InterruptedException {
+    public static int shiftRight(Context ctx, Object a, Object b) {
        return (int)toNumber(ctx, a) >> (int)toNumber(ctx, b);
    }
-    public static long unsignedShiftRight(Context ctx, Object a, Object b) throws InterruptedException {
+    public static long unsignedShiftRight(Context ctx, Object a, Object b) {
        long _a = (long)toNumber(ctx, a);
        long _b = (long)toNumber(ctx, b);

@@ -195,19 +210,25 @@ public class Values {
        return _a >>> _b;
    }

-    public static int compare(Context ctx, Object a, Object b) throws InterruptedException {
+    public static CompareResult compare(Context ctx, Object a, Object b) {
        a = toPrimitive(ctx, a, ConvertHint.VALUEOF);
        b = toPrimitive(ctx, b, ConvertHint.VALUEOF);

-        if (a instanceof String && b instanceof String) return ((String)a).compareTo((String)b);
-        else return Double.compare(toNumber(ctx, a), toNumber(ctx, b));
+        if (a instanceof String && b instanceof String) CompareResult.from(((String)a).compareTo((String)b));
+
+        var _a = toNumber(ctx, a);
+        var _b = toNumber(ctx, b);
+
+        if (Double.isNaN(_a) || Double.isNaN(_b)) return CompareResult.NOT_EQUAL;
+
+        return CompareResult.from(Double.compare(_a, _b));
    }

    public static boolean not(Object obj) {
        return !toBoolean(obj);
    }

-    public static boolean isInstanceOf(Context ctx, Object obj, Object proto) throws InterruptedException {
+    public static boolean isInstanceOf(Context ctx, Object obj, Object proto) {
        if (obj == null || obj == NULL || proto == null || proto == NULL) return false;
        var val = getPrototype(ctx, obj);

@@ -219,7 +240,7 @@ public class Values {
        return false;
    }

-    public static Object operation(Context ctx, Operation op, Object ...args) throws InterruptedException {
+    public static Object operation(Context ctx, Operation op, Object ...args) {
        switch (op) {
            case ADD: return add(ctx, args[0], args[1]);
            case SUBTRACT: return subtract(ctx, args[0], args[1]);
@@ -236,10 +257,10 @@ public class Values {
            case LOOSE_EQUALS: return looseEqual(ctx, args[0], args[1]);
            case LOOSE_NOT_EQUALS: return !looseEqual(ctx, args[0], args[1]);

-            case GREATER: return compare(ctx, args[0], args[1]) > 0;
-            case GREATER_EQUALS: return compare(ctx, args[0], args[1]) >= 0;
-            case LESS: return compare(ctx, args[0], args[1]) < 0;
-            case LESS_EQUALS: return compare(ctx, args[0], args[1]) <= 0;
+            case GREATER: return compare(ctx, args[0], args[1]).greater();
+            case GREATER_EQUALS: return compare(ctx, args[0], args[1]).greaterOrEqual();
+            case LESS: return compare(ctx, args[0], args[1]).less();
+            case LESS_EQUALS: return compare(ctx, args[0], args[1]).lessOrEqual();

            case INVERSE: return bitwiseNot(ctx, args[0]);
            case NOT: return not(args[0]);
@@ -260,7 +281,7 @@ public class Values {
        }
    }

-    public static Object getMember(Context ctx, Object obj, Object key) throws InterruptedException {
+    public static Object getMember(Context ctx, Object obj, Object key) {
        obj = normalize(ctx, obj); key = normalize(ctx, key);
        if (obj == null) throw new IllegalArgumentException("Tried to access member of undefined.");
        if (obj == NULL) throw new IllegalArgumentException("Tried to access member of null.");
@@ -276,25 +297,30 @@ public class Values {

        var proto = getPrototype(ctx, obj);

-        if (proto == null) return key.equals("__proto__") ? NULL : null;
-        else if (key != null && key.equals("__proto__")) return proto;
+        if (proto == null) return "__proto__".equals(key) ? NULL : null;
+        else if (key != null && "__proto__".equals(key)) return proto;
        else return proto.getMember(ctx, key, obj);
    }
-    public static boolean setMember(Context ctx, Object obj, Object key, Object val) throws InterruptedException {
+    public static Object getMemberPath(Context ctx, Object obj, Object ...path) {
+        var res = obj;
+        for (var key : path) res = getMember(ctx, res, key);
+        return res;
+    }
+    public static boolean setMember(Context ctx, Object obj, Object key, Object val) {
        obj = normalize(ctx, obj); key = normalize(ctx, key); val = normalize(ctx, val);
        if (obj == null) throw EngineException.ofType("Tried to access member of undefined.");
        if (obj == NULL) throw EngineException.ofType("Tried to access member of null.");
-        if (key.equals("__proto__")) return setPrototype(ctx, obj, val);
+        if (key != null && "__proto__".equals(key)) return setPrototype(ctx, obj, val);
        if (isObject(obj)) return object(obj).setMember(ctx, key, val, false);

        var proto = getPrototype(ctx, obj);
        return proto.setMember(ctx, key, val, obj, true);
    }
-    public static boolean hasMember(Context ctx, Object obj, Object key, boolean own) throws InterruptedException {
+    public static boolean hasMember(Context ctx, Object obj, Object key, boolean own) {
        if (obj == null || obj == NULL) return false;
        obj = normalize(ctx, obj); key = normalize(ctx, key);

-        if (key.equals("__proto__")) return true;
+        if ("__proto__".equals(key)) return true;
        if (isObject(obj)) return object(obj).hasMember(ctx, key, own);

        if (obj instanceof String && key instanceof Number) {
@@ -308,31 +334,31 @@ public class Values {
        var proto = getPrototype(ctx, obj);
        return proto != null && proto.hasMember(ctx, key, own);
    }
-    public static boolean deleteMember(Context ctx, Object obj, Object key) throws InterruptedException {
+    public static boolean deleteMember(Context ctx, Object obj, Object key) {
        if (obj == null || obj == NULL) return false;
        obj = normalize(ctx, obj); key = normalize(ctx, key);

        if (isObject(obj)) return object(obj).deleteMember(ctx, key);
        else return false;
    }
-    public static ObjectValue getPrototype(Context ctx, Object obj) throws InterruptedException {
+    public static ObjectValue getPrototype(Context ctx, Object obj) {
        if (obj == null || obj == NULL) return null;
        obj = normalize(ctx, obj);
        if (isObject(obj)) return object(obj).getPrototype(ctx);
        if (ctx == null) return null;

-        if (obj instanceof String) return ctx.env.proto("string");
-        else if (obj instanceof Number) return ctx.env.proto("number");
-        else if (obj instanceof Boolean) return ctx.env.proto("bool");
-        else if (obj instanceof Symbol) return ctx.env.proto("symbol");
+        if (obj instanceof String) return ctx.environment().proto("string");
+        else if (obj instanceof Number) return ctx.environment().proto("number");
+        else if (obj instanceof Boolean) return ctx.environment().proto("bool");
+        else if (obj instanceof Symbol) return ctx.environment().proto("symbol");

        return null;
    }
-    public static boolean setPrototype(Context ctx, Object obj, Object proto) throws InterruptedException {
+    public static boolean setPrototype(Context ctx, Object obj, Object proto) {
        obj = normalize(ctx, obj);
        return isObject(obj) && object(obj).setPrototype(ctx, proto);
    }
-    public static List<Object> getMembers(Context ctx, Object obj, boolean own, boolean includeNonEnumerable) throws InterruptedException {  
+    public static List<Object> getMembers(Context ctx, Object obj, boolean own, boolean includeNonEnumerable) {  
        List<Object> res = new ArrayList<>();

        if (isObject(obj)) res = object(obj).keys(includeNonEnumerable);
@@ -352,7 +378,7 @@ public class Values {

        return res;
    }
-    public static ObjectValue getMemberDescriptor(Context ctx, Object obj, Object key) throws InterruptedException {
+    public static ObjectValue getMemberDescriptor(Context ctx, Object obj, Object key) {
        if (obj instanceof ObjectValue) return ((ObjectValue)obj).getMemberDescriptor(ctx, key);
        else if (obj instanceof String && key instanceof Number) {
            var i = ((Number)key).intValue();
@@ -370,19 +396,24 @@ public class Values {
        else return null;
    }

-    public static Object call(Context ctx, Object func, Object thisArg, Object ...args) throws InterruptedException {
+    public static Object call(Context ctx, Object func, Object thisArg, Object ...args) {
        if (!isFunction(func)) throw EngineException.ofType("Tried to call a non-function value.");
        return function(func).call(ctx, thisArg, args);
    }
-    public static Object callNew(Context ctx, Object func, Object ...args) throws InterruptedException {
+    public static Object callNew(Context ctx, Object func, Object ...args) {
        var res = new ObjectValue();
-        var proto = Values.getMember(ctx, func, "prototype");
-        res.setPrototype(ctx, proto);
-
-        var ret = call(ctx, func, res, args);
-
-        if (ret != null && func instanceof FunctionValue && ((FunctionValue)func).special) return ret;
-        return res;
+        try {
+            var proto = Values.getMember(ctx, func, "prototype");
+            res.setPrototype(ctx, proto);
+    
+            var ret = call(ctx, func, res, args);
+    
+            if (ret != null && func instanceof FunctionValue && ((FunctionValue)func).special) return ret;
+            return res;
+        }
+        catch (IllegalArgumentException e) {
+            throw EngineException.ofType("Tried to call new on an invalid constructor.");
+        }
    }

    public static boolean strictEquals(Context ctx, Object a, Object b) {
@@ -395,7 +426,7 @@ public class Values {

        return a == b || a.equals(b);
    }
-    public static boolean looseEqual(Context ctx, Object a, Object b) throws InterruptedException {
+    public static boolean looseEqual(Context ctx, Object a, Object b) {
        a = normalize(ctx, a); b = normalize(ctx, b);

        // In loose equality, null is equivalent to undefined
@@ -446,14 +477,14 @@ public class Values {

        if (val instanceof Class) {
            if (ctx == null) return null;
-            else return ctx.env.wrappersProvider.getConstr((Class<?>)val);
+            else return ctx.environment().wrappers.getConstr((Class<?>)val);
        }

        return new NativeWrapper(val);
    }

    @SuppressWarnings("unchecked")
-    public static <T> T convert(Context ctx, Object obj, Class<T> clazz) throws InterruptedException {
+    public static <T> T convert(Context ctx, Object obj, Class<T> clazz) {
        if (clazz == Void.class) return null;

        if (obj instanceof NativeWrapper) {
@@ -517,10 +548,10 @@ public class Values {
        throw new ConvertException(type(obj), clazz.getSimpleName());
    }

-    public static Iterable<Object> toJavaIterable(Context ctx, Object obj) {
+    public static Iterable<Object> fromJSIterator(Context ctx, Object obj) {
        return () -> {
            try {
-                var symbol = ctx.env.symbol("Symbol.iterator");
+                var symbol = ctx.environment().symbol("Symbol.iterator");

                var iteratorFunc = getMember(ctx, obj, symbol);
                if (!isFunction(iteratorFunc)) return Collections.emptyIterator();
@@ -536,7 +567,7 @@ public class Values {
                    public boolean consumed = true;
                    private FunctionValue next = (FunctionValue)nextFunc;

-                    private void loadNext() throws InterruptedException {
+                    private void loadNext() {
                        if (next == null) value = null;
                        else if (consumed) {
                            var curr = object(next.call(ctx, iterator));
@@ -551,63 +582,89 @@ public class Values {

                    @Override
                    public boolean hasNext() {
-                        try {
-                            loadNext();
-                            return next != null;
-                        }
-                        catch (InterruptedException e) {
-                            Thread.currentThread().interrupt();
-                            return false;
-                        }
+                        loadNext();
+                        return next != null;
                    }
                    @Override
                    public Object next() {
-                        try {
-                            loadNext();
-                            var res = value;
-                            value = null;
-                            consumed = true;
-                            return res;
-                        }
-                        catch (InterruptedException e) {
-                            Thread.currentThread().interrupt();
-                            return null;
-                        }
+                        loadNext();
+                        var res = value;
+                        value = null;
+                        consumed = true;
+                        return res;
                    }
                };
            }
-            catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
-                return null;
-            }
            catch (IllegalArgumentException | NullPointerException e) {
                return Collections.emptyIterator();
            }
        };
    }

-    public static ObjectValue fromJavaIterator(Context ctx, Iterator<?> it) throws InterruptedException {
+    public static ObjectValue toJSIterator(Context ctx, Iterator<?> it) {
        var res = new ObjectValue();

        try {
-            var key = getMember(ctx, getMember(ctx, ctx.env.proto("symbol"), "constructor"), "iterator");
+            var key = getMember(ctx, getMember(ctx, ctx.environment().proto("symbol"), "constructor"), "iterator");
            res.defineProperty(ctx, key, new NativeFunction("", (_ctx, thisArg, args) -> thisArg));
        }
        catch (IllegalArgumentException | NullPointerException e) { }

        res.defineProperty(ctx, "next", new NativeFunction("", (_ctx, _th, _args) -> {
            if (!it.hasNext()) return new ObjectValue(ctx, Map.of("done", true));
-            else return new ObjectValue(ctx, Map.of("value", it.next()));
+            else {
+                var obj = new ObjectValue();
+                obj.defineProperty(_ctx, "value", it.next());
+                return obj;
+            }
        }));

        return res;
    }

-    public static ObjectValue fromJavaIterable(Context ctx, Iterable<?> it) throws InterruptedException {
-        return fromJavaIterator(ctx, it.iterator());
+    public static ObjectValue toJSIterator(Context ctx, Iterable<?> it) {
+        return toJSIterator(ctx, it.iterator());
    }

-    private static void printValue(Context ctx, Object val, HashSet<Object> passed, int tab) throws InterruptedException {
+    public static ObjectValue toJSAsyncIterator(Context ctx, Iterator<?> it) {
+        var res = new ObjectValue();
+
+        try {
+            var key = getMemberPath(ctx, ctx.environment().proto("symbol"), "constructor", "asyncIterator");
+            res.defineProperty(ctx, key, new NativeFunction("", (_ctx, thisArg, args) -> thisArg));
+        }
+        catch (IllegalArgumentException | NullPointerException e) { }
+
+        res.defineProperty(ctx, "next", new NativeFunction("", (_ctx, _th, _args) -> {
+            return PromiseLib.await(ctx, () -> {
+                if (!it.hasNext()) return new ObjectValue(ctx, Map.of("done", true));
+                else {
+                    var obj = new ObjectValue();
+                    obj.defineProperty(_ctx, "value", it.next());
+                    return obj;
+                }
+            });
+        }));
+
+        return res;
+    }
+
+    private static boolean isEmptyFunc(ObjectValue val) {
+        if (!(val instanceof FunctionValue)) return false;
+        if (!val.values.containsKey("prototype") || val.values.size() + val.properties.size() > 1) return false;
+        var proto = val.values.get("prototype");
+        if (!(proto instanceof ObjectValue)) return false;
+        var protoObj = (ObjectValue)proto;
+        if (protoObj.values.get("constructor") != val) return false;
+        if (protoObj.values.size() + protoObj.properties.size() != 1) return false;
+        return true;
+    }
+    private static void printValue(Context ctx, Object val, HashSet<Object> passed, int tab) {
+        if (tab == 0 && val instanceof String) {
+            System.out.print(val);
+            return;
+        }
+
        if (passed.contains(val)) {
            System.out.print("[circular]");
            return;
@@ -616,10 +673,7 @@ public class Values {
        var printed = true;

        if (val instanceof FunctionValue) {
-            System.out.print("function ");
-            var name = Values.getMember(ctx, val, "name");
-            if (name != null) System.out.print(Values.toString(ctx, name));
-            System.out.print("(...)");
+            System.out.print(val.toString());
            var loc = val instanceof CodeFunction ? ((CodeFunction)val).loc() : null;

            if (loc != null) System.out.print(" @ " + loc);
@@ -649,7 +703,7 @@ public class Values {
            passed.add(val);

            var obj = (ObjectValue)val;
-            if (obj.values.size() + obj.properties.size() == 0) {
+            if (obj.values.size() + obj.properties.size() == 0 || isEmptyFunc(obj)) {
                if (!printed) System.out.println("{}");
            }
            else {
@@ -667,26 +721,28 @@ public class Values {
                    printValue(ctx, el.getKey(), passed, tab + 1);
                    System.out.println(": [prop],");
                }
-    
+
                for (int i = 0; i < tab; i++) System.out.print("    ");
                System.out.print("}");
-    
-                passed.remove(val);
+
            }
+
+            passed.remove(val);
        }
        else if (val == null) System.out.print("undefined");
        else if (val == Values.NULL) System.out.print("null");
        else if (val instanceof String) System.out.print("'" + val + "'");
        else System.out.print(Values.toString(ctx, val));
    }
-    public static void printValue(Context ctx, Object val) throws InterruptedException {
+    public static void printValue(Context ctx, Object val) {
        printValue(ctx, val, new HashSet<>(), 0);
    }
-    public static void printError(RuntimeException err, String prefix) throws InterruptedException {
+    public static void printError(RuntimeException err, String prefix) {
        prefix = prefix == null ? "Uncaught" : "Uncaught " + prefix;
        try {
            if (err instanceof EngineException) {
-                System.out.println(prefix + " " + ((EngineException)err).toString(((EngineException)err).ctx));
+                var ee = ((EngineException)err);
+                System.out.println(prefix + " " + ee.toString(new Context(ee.engine).pushEnv(ee.env)));
            }
            else if (err instanceof SyntaxException) {
                System.out.println("Syntax error:" + ((SyntaxException)err).msg);
--- a/src/me/topchetoeu/jscript/events/Awaitable.java
+++ b/src/me/topchetoeu/jscript/events/Awaitable.java
@@ -1,7 +1,9 @@
 package me.topchetoeu.jscript.events;

+import me.topchetoeu.jscript.exceptions.InterruptException;
+
 public interface Awaitable<T> {
-    T await() throws FinishedException, InterruptedException;
+    T await() throws FinishedException;

    default Observable<T> toObservable() {
        return sub -> {
@@ -10,9 +12,7 @@ public interface Awaitable<T> {
                    sub.next(await());
                    sub.finish();
                }
-                catch (InterruptedException | FinishedException e) {
-                    sub.finish();
-                }
+                catch (InterruptException | FinishedException e) { sub.finish(); }
                catch (RuntimeException e) {
                    sub.error(e);
                }
--- a/src/me/topchetoeu/jscript/events/DataNotifier.java
+++ b/src/me/topchetoeu/jscript/events/DataNotifier.java
@@ -19,7 +19,7 @@ public class DataNotifier<T> implements Awaitable<T> {
        isErr = false;
        notifier.next();
    }
-    public T await() throws InterruptedException {
+    public T await() {
        notifier.await();

        try {
--- a/src/me/topchetoeu/jscript/events/Notifier.java
+++ b/src/me/topchetoeu/jscript/events/Notifier.java
@@ -1,5 +1,7 @@
 package me.topchetoeu.jscript.events;

+import me.topchetoeu.jscript.exceptions.InterruptException;
+
 public class Notifier {
    private boolean ok = false;

@@ -7,8 +9,11 @@ public class Notifier {
        ok = true;
        notifyAll();
    }
-    public synchronized void await() throws InterruptedException {
-        while (!ok) wait();
-        ok = false;
+    public synchronized void await() {
+        try {
+            while (!ok) wait();
+            ok = false;
+        }
+        catch (InterruptedException e) { throw new InterruptException(e); }
    }
 }
--- a/src/me/topchetoeu/jscript/exceptions/EngineException.java
+++ b/src/me/topchetoeu/jscript/exceptions/EngineException.java
@@ -5,6 +5,8 @@ import java.util.List;

 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.Engine;
+import me.topchetoeu.jscript.engine.Environment;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.engine.values.ObjectValue.PlaceholderProto;
@@ -12,7 +14,8 @@ import me.topchetoeu.jscript.engine.values.ObjectValue.PlaceholderProto;
 public class EngineException extends RuntimeException {
    public final Object value;
    public EngineException cause;
-    public Context ctx = null;
+    public Environment env = null;
+    public Engine engine = null;
    public final List<String> stackTrace = new ArrayList<>();

    public EngineException add(String name, Location location) {
@@ -28,12 +31,13 @@ public class EngineException extends RuntimeException {
        this.cause = cause;
        return this;
    }
-    public EngineException setContext(Context ctx) {
-        this.ctx = ctx;
+    public EngineException setCtx(Environment env, Engine engine) {
+        if (this.env == null) this.env = env;
+        if (this.engine == null) this.engine = engine;
        return this;
    }

-    public String toString(Context ctx) throws InterruptedException {
+    public String toString(Context ctx) {
        var ss = new StringBuilder();
        try {
            ss.append(Values.toString(ctx, value)).append('\n');
@@ -41,10 +45,10 @@ public class EngineException extends RuntimeException {
        catch (EngineException e) {
            ss.append("[Error while stringifying]\n");
        }
-        // for (var line : stackTrace) {
-        //     ss.append("    ").append(line).append('\n');
-        // }
-        // if (cause != null) ss.append("Caused by ").append(cause.toString(ctx)).append('\n');
+        for (var line : stackTrace) {
+            ss.append("    ").append(line).append('\n');
+        }
+        if (cause != null) ss.append("Caused by ").append(cause.toString(ctx)).append('\n');
        ss.deleteCharAt(ss.length() - 1);
        return ss.toString();
    }
--- a/src/me/topchetoeu/jscript/exceptions/InterruptException.java
+++ b/src/me/topchetoeu/jscript/exceptions/InterruptException.java
@@ -0,0 +1,8 @@
+package me.topchetoeu.jscript.exceptions;
+
+public class InterruptException extends RuntimeException {
+    public InterruptException() { }
+    public InterruptException(Throwable e) {
+        super(e);
+    }
+}
--- a/src/me/topchetoeu/jscript/exceptions/UncheckedException.java
+++ b/src/me/topchetoeu/jscript/exceptions/UncheckedException.java
@@ -0,0 +1,7 @@
+package me.topchetoeu.jscript.exceptions;
+
+public class UncheckedException extends RuntimeException {
+    public UncheckedException(Throwable err) {
+        super(err);
+    }
+}
--- a/src/me/topchetoeu/jscript/exceptions/UncheckedIOException.java
+++ b/src/me/topchetoeu/jscript/exceptions/UncheckedIOException.java
@@ -0,0 +1,9 @@
+package me.topchetoeu.jscript.exceptions;
+
+import java.io.IOException;
+
+public class UncheckedIOException extends RuntimeException {
+    public UncheckedIOException(IOException e) {
+        super(e);
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/Buffer.java
+++ b/src/me/topchetoeu/jscript/filesystem/Buffer.java
@@ -0,0 +1,41 @@
+package me.topchetoeu.jscript.filesystem;
+
+public class Buffer {
+    private byte[] data;
+    private int length;
+
+    public void write(int i, byte[] val) {
+        if (i + val.length > data.length) {
+            var newCap = i + val.length + 1;
+            if (newCap < data.length * 2) newCap = data.length * 2;
+
+            var tmp = new byte[newCap];
+            System.arraycopy(this.data, 0, tmp, 0, length);
+            this.data = tmp;
+        }
+
+        System.arraycopy(val, 0, data, i, val.length);
+        if (i + val.length > length) length = i + val.length;
+    }
+    public int read(int i, byte[] buff) {
+        int n = buff.length;
+        if (i + n > length) n = length - i;
+        System.arraycopy(data, i, buff, 0, n);
+        return n;
+    }
+
+    public byte[] data() {
+        var res = new byte[length];
+        System.arraycopy(this.data, 0, res, 0, length);
+        return res;
+    }
+    public int length() {
+        return length;
+    }
+
+    public Buffer(byte[] data) {
+        this.data = new byte[data.length];
+        this.length = data.length;
+        System.arraycopy(data, 0, this.data, 0, data.length);
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/EntryType.java
+++ b/src/me/topchetoeu/jscript/filesystem/EntryType.java
@@ -1,7 +1,13 @@
 package me.topchetoeu.jscript.filesystem;

 public enum EntryType {
-    NONE,
-    FILE,
-    FOLDER,
+    NONE("none"),
+    FILE("file"),
+    FOLDER("folder");
+
+    public final String name;
+
+    private EntryType(String name) {
+        this.name = name;
+    }
 }
--- a/src/me/topchetoeu/jscript/filesystem/File.java
+++ b/src/me/topchetoeu/jscript/filesystem/File.java
@@ -1,27 +1,39 @@
 package me.topchetoeu.jscript.filesystem;

-import java.io.IOException;
-
 public interface File {
-    int read() throws IOException, InterruptedException;
-    boolean write(byte val) throws IOException, InterruptedException;
-    long tell() throws IOException, InterruptedException;
-    void seek(long offset, int pos) throws IOException, InterruptedException;
-    void close() throws IOException, InterruptedException;
-    Permissions perms();
+    int read(byte[] buff);
+    void write(byte[] buff);
+    long getPtr();
+    void setPtr(long offset, int pos);
+    void close();
+    Mode mode();

-    default String readToString() throws IOException, InterruptedException {
-        seek(0, 2);
-        long len = tell();
+    default String readToString() {
+        setPtr(0, 2);
+        long len = getPtr();
        if (len < 0) return null;

-        seek(0, 0);
-        byte[] res = new byte[(int)len];
+        setPtr(0, 0);

-        for (var i = 0; i < len; i++) {
-            res[i] = (byte)read();
-        }
+        byte[] res = new byte[(int)len];
+        read(res);

        return new String(res);
    }
+    default String readLine() {
+        var res = new Buffer(new byte[0]);
+        var buff = new byte[1];
+
+        while (true) {
+            if (read(buff) == 0) {
+                if (res.length() == 0) return null;
+                else break;
+            }
+
+            if (buff[0] == '\n') break;
+
+            res.write(res.length(), buff);
+        }
+        return new String(res.data());
+    }
 }
--- a/src/me/topchetoeu/jscript/filesystem/FileStat.java
+++ b/src/me/topchetoeu/jscript/filesystem/FileStat.java
@@ -0,0 +1,11 @@
+package me.topchetoeu.jscript.filesystem;
+
+public class FileStat {
+    public final Mode mode;
+    public final EntryType type;
+
+    public FileStat(Mode mode, EntryType type) {
+        this.mode = mode;
+        this.type = type;
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/Filesystem.java
+++ b/src/me/topchetoeu/jscript/filesystem/Filesystem.java
@@ -1,10 +1,7 @@
 package me.topchetoeu.jscript.filesystem;

-import java.io.IOException;
-
 public interface Filesystem {
-    File open(String path) throws IOException, InterruptedException;
-    boolean mkdir(String path) throws IOException, InterruptedException;
-    EntryType type(String path) throws IOException, InterruptedException;
-    boolean rm(String path) throws IOException, InterruptedException;
-}
+    File open(String path, Mode mode) throws FilesystemException;
+    void create(String path, EntryType type) throws FilesystemException;
+    FileStat stat(String path) throws FilesystemException;
+}
--- a/src/me/topchetoeu/jscript/filesystem/FilesystemException.java
+++ b/src/me/topchetoeu/jscript/filesystem/FilesystemException.java
@@ -0,0 +1,55 @@
+package me.topchetoeu.jscript.filesystem;
+
+import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.exceptions.EngineException;
+
+public class FilesystemException extends RuntimeException {
+    public static enum FSCode {
+        DOESNT_EXIST(0x1),
+        NOT_FILE(0x2),
+        NOT_FOLDER(0x3),
+        NO_PERMISSIONS_R(0x4),
+        NO_PERMISSIONS_RW(0x5),
+        FOLDER_NOT_EMPTY(0x6),
+        ALREADY_EXISTS(0x7),
+        FOLDER_EXISTS(0x8);
+
+        public final int code;
+
+        private FSCode(int code) { this.code = code; }
+    }
+
+    public static final String[] MESSAGES = {
+        "How did we get here?",
+        "The file or folder '%s' doesn't exist or is inaccessible.",
+        "'%s' is not a file",
+        "'%s' is not a folder",
+        "No permissions to read '%s'",
+        "No permissions to write '%s'",
+        "Can't delete '%s', since it is a full folder.",
+        "'%s' already exists."
+    };
+
+    public final String message, filename;
+    public final FSCode code;
+
+    public FilesystemException(String message, String filename, FSCode code) {
+        super(code + ": " + String.format(message, filename));
+        this.message = message;
+        this.code = code;
+        this.filename = filename;
+    }
+    public FilesystemException(String filename, FSCode code) {
+        super(code + ": " + String.format(MESSAGES[code.code], filename));
+        this.message = MESSAGES[code.code];
+        this.code = code;
+        this.filename = filename;
+    }
+
+    public EngineException toEngineException() {
+        var res = EngineException.ofError("IOError", getMessage());
+        Values.setMember(null, res.value, "code", code);
+        Values.setMember(null, res.value, "filename", filename.toString());
+        return res;
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/InaccessibleFile.java
+++ b/src/me/topchetoeu/jscript/filesystem/InaccessibleFile.java
@@ -1,35 +0,0 @@
-package me.topchetoeu.jscript.filesystem;
-
-import java.io.IOException;
-
-public class InaccessibleFile implements File {
-    public static final InaccessibleFile INSTANCE = new InaccessibleFile();
-
-    @Override
-    public int read() throws IOException, InterruptedException {
-        return -1;
-    }
-
-    @Override
-    public boolean write(byte val) throws IOException, InterruptedException {
-        return false;
-    }
-
-    @Override
-    public long tell() throws IOException, InterruptedException {
-        return 0;
-    }
-
-    @Override
-    public void seek(long offset, int pos) throws IOException, InterruptedException { }
-
-    @Override
-    public void close() throws IOException, InterruptedException { }
-
-    @Override
-    public Permissions perms() {
-        return Permissions.NONE;
-    }
-
-    private InaccessibleFile() { }
-}
--- a/src/me/topchetoeu/jscript/filesystem/MemoryFile.java
+++ b/src/me/topchetoeu/jscript/filesystem/MemoryFile.java
@@ -1,53 +1,66 @@
 package me.topchetoeu.jscript.filesystem;

-import java.io.IOException;
+import me.topchetoeu.jscript.filesystem.FilesystemException.FSCode;

 public class MemoryFile implements File {
    private int ptr;
-    private Permissions mode;
-    public final byte[] data;
+    private Mode mode;
+    private Buffer data;
+    private String filename;
+
+    public Buffer data() { return data; }

    @Override
-    public int read() throws IOException, InterruptedException {
-        if (data == null || !mode.readable || ptr >= data.length) return -1;
-        return data[ptr++];
+    public int read(byte[] buff) {
+        if (data == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
+        var res = data.read(ptr, buff);
+        ptr += res;
+        return res;
+    }
+    @Override
+    public void write(byte[] buff) {
+        if (data == null || !mode.writable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW);
+
+        data.write(ptr, buff);
+        ptr += buff.length;
    }

    @Override
-    public boolean write(byte val) throws IOException, InterruptedException {
-        if (data == null || !mode.writable || ptr >= data.length) return false;
-        data[ptr++] = val;
-        return true;
-    }
-
-    @Override
-    public long tell() throws IOException, InterruptedException {
+    public long getPtr() {
+        if (data == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
        return ptr;
    }
-
    @Override
-    public void seek(long offset, int pos) throws IOException, InterruptedException {
-        if (data == null) return;
+    public void setPtr(long offset, int pos) {
+        if (data == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);

        if (pos == 0) ptr = (int)offset;
        else if (pos == 1) ptr += (int)offset;
-        else if (pos == 2) ptr = data.length - (int)offset;
+        else if (pos == 2) ptr = data.length() - (int)offset;
    }

    @Override
-    public void close() throws IOException, InterruptedException {
-        mode = null;
+    public void close() {
+        mode = Mode.NONE;
        ptr = 0;
    }
-
    @Override
-    public Permissions perms() {
-        if (data == null) return Permissions.NONE;
+    public Mode mode() {
+        if (data == null) return Mode.NONE;
        return mode;
    }

-    public MemoryFile(byte[] buff, Permissions mode) {
+    public MemoryFile(String filename, Buffer buff, Mode mode) {
+        this.filename = filename;
        this.data = buff;
        this.mode = mode;
    }
+
+    public static MemoryFile fromFileList(String filename, java.io.File[] list) {
+        var res = new StringBuilder();
+
+        for (var el : list) res.append(el.getName()).append('\n');
+
+        return new MemoryFile(filename, new Buffer(res.toString().getBytes()), Mode.READ);
+    }
 }
--- a/src/me/topchetoeu/jscript/filesystem/MemoryFilesystem.java
+++ b/src/me/topchetoeu/jscript/filesystem/MemoryFilesystem.java
@@ -0,0 +1,89 @@
+package me.topchetoeu.jscript.filesystem;
+
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.HashSet;
+
+import me.topchetoeu.jscript.filesystem.FilesystemException.FSCode;
+
+public class MemoryFilesystem implements Filesystem {
+    public final Mode mode;
+    private HashMap<Path, Buffer> files = new HashMap<>();
+    private HashSet<Path> folders = new HashSet<>();
+
+    private Path getPath(String name) {
+        return Path.of("/" + name.replace("\\", "/")).normalize();
+    }
+
+    @Override
+    public void create(String path, EntryType type) {
+        var _path = getPath(path);
+
+        switch (type) {
+            case FILE:
+                if (!folders.contains(_path.getParent())) throw new FilesystemException(path, FSCode.DOESNT_EXIST);
+                if (folders.contains(_path) || files.containsKey(_path)) throw new FilesystemException(path, FSCode.ALREADY_EXISTS);
+                if (folders.contains(_path)) throw new FilesystemException(path, FSCode.ALREADY_EXISTS);
+                files.put(_path, new Buffer(new byte[0]));
+                break;
+            case FOLDER:
+                if (!folders.contains(_path.getParent())) throw new FilesystemException(path, FSCode.DOESNT_EXIST);
+                if (folders.contains(_path) || files.containsKey(_path)) throw new FilesystemException(path, FSCode.ALREADY_EXISTS);
+                folders.add(_path);
+                break;
+            default:
+            case NONE:
+                if (!folders.remove(_path) && files.remove(_path) == null) throw new FilesystemException(path, FSCode.DOESNT_EXIST);
+        }
+    }
+
+    @Override
+    public File open(String path, Mode perms) {
+        var _path = getPath(path);
+        var pcount = _path.getNameCount();
+
+        if (files.containsKey(_path)) return new MemoryFile(path, files.get(_path), perms);
+        else if (folders.contains(_path)) {
+            var res = new StringBuilder();
+            for (var folder : folders) {
+                if (pcount + 1 != folder.getNameCount()) continue;
+                if (!folder.startsWith(_path)) continue;
+                res.append(folder.toFile().getName()).append('\n');
+            }
+            for (var file : files.keySet()) {
+                if (pcount + 1 != file.getNameCount()) continue;
+                if (!file.startsWith(_path)) continue;
+                res.append(file.toFile().getName()).append('\n');
+            }
+            return new MemoryFile(path, new Buffer(res.toString().getBytes()), perms.intersect(Mode.READ));
+        }
+        else throw new FilesystemException(path, FSCode.DOESNT_EXIST);
+    }
+
+    @Override
+    public FileStat stat(String path) {
+        var _path = getPath(path);
+
+        if (files.containsKey(_path)) return new FileStat(mode, EntryType.FILE);
+        else if (folders.contains(_path)) return new FileStat(mode, EntryType.FOLDER);
+        else throw new FilesystemException(path, FSCode.DOESNT_EXIST);
+    }
+
+    public MemoryFilesystem put(String path, byte[] data) {
+        var _path = getPath(path);
+        var _curr = "/";
+
+        for (var seg : _path) {
+            create(_curr, EntryType.FOLDER);
+            _curr += seg + "/";
+        }
+
+        files.put(_path, new Buffer(data));
+        return this;
+    }
+
+    public MemoryFilesystem(Mode mode) {
+        this.mode = mode;
+        folders.add(Path.of("/"));
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/Mode.java
+++ b/src/me/topchetoeu/jscript/filesystem/Mode.java
@@ -0,0 +1,31 @@
+package me.topchetoeu.jscript.filesystem;
+
+public enum Mode {
+    NONE("", false, false),
+    READ("r", true, false),
+    READ_WRITE("rw", true, true);
+
+    public final String name;
+    public final boolean readable;
+    public final boolean writable;
+
+    public Mode intersect(Mode other) {
+        if (this == NONE || other == NONE) return NONE;
+        if (this == READ_WRITE && other == READ_WRITE) return READ_WRITE;
+        return READ;
+    }
+
+    private Mode(String mode, boolean r, boolean w) {
+        this.name = mode;
+        this.readable = r;
+        this.writable = w;
+    }
+
+    public static Mode parse(String mode) {
+        switch (mode) {
+            case "r": return READ;
+            case "rw": return READ_WRITE;
+            default: return NONE;
+        }
+    }
+}
--- a/src/me/topchetoeu/jscript/filesystem/Permissions.java
+++ b/src/me/topchetoeu/jscript/filesystem/Permissions.java
@@ -1,17 +0,0 @@
-package me.topchetoeu.jscript.filesystem;
-
-public enum Permissions {
-    NONE("", false, false),
-    READ("r", true, false),
-    READ_WRITE("rw", true, true);
-
-    public final String readMode;
-    public final boolean readable;
-    public final boolean writable;
-
-    private Permissions(String mode, boolean r, boolean w) {
-        this.readMode = mode;
-        this.readable = r;
-        this.writable = w;
-    }
-}
--- a/src/me/topchetoeu/jscript/filesystem/PhysicalFile.java
+++ b/src/me/topchetoeu/jscript/filesystem/PhysicalFile.java
@@ -1,50 +1,62 @@
 package me.topchetoeu.jscript.filesystem;

+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;

+import me.topchetoeu.jscript.filesystem.FilesystemException.FSCode;
+
 public class PhysicalFile implements File {
+    private String filename;
    private RandomAccessFile file;
-    private Permissions perms;
+    private Mode perms;

    @Override
-    public int read() throws IOException, InterruptedException {
-        if (file == null || !perms.readable) return -1;
-        else return file.read();
+    public int read(byte[] buff) {
+        if (file == null || !perms.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
+        else try { return file.read(buff); }
+        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R); }
+    }
+    @Override
+    public void write(byte[] buff) {
+        if (file == null || !perms.writable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW);
+        else try { file.write(buff); }
+        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW); }
    }

    @Override
-    public boolean write(byte val) throws IOException, InterruptedException {
-        if (file == null || !perms.writable) return false;
-        file.write(val);
-        return true;
+    public long getPtr() {
+        if (file == null || !perms.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
+        else try { return file.getFilePointer(); }
+        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R); }
+    }
+    @Override
+    public void setPtr(long offset, int pos) {
+        if (file == null || !perms.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
+
+        try {
+            if (pos == 1) pos += file.getFilePointer();
+            else if (pos == 2) pos += file.length();
+            file.seek(pos);
+        }
+        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R); }
    }

    @Override
-    public long tell() throws IOException, InterruptedException {
-        if (file == null) return 0;
-        return file.getFilePointer();
-    }
-    @Override
-    public void seek(long offset, int pos) throws IOException, InterruptedException {
+    public void close() {
        if (file == null) return;
-        if (pos == 0) file.seek(pos);
-        else if (pos == 1) file.seek(file.getFilePointer() + pos);
-        else if (pos == 2) file.seek(file.length() + pos);
+        try { file.close(); }
+        catch (IOException e) {} // SHUT
+        file = null;
+        perms = Mode.NONE;
    }
-
    @Override
-    public void close() throws IOException, InterruptedException {
-        if (file == null) return;
-        file.close();
-    }
+    public Mode mode() { return perms; }

-    @Override
-    public Permissions perms() { return perms; }
-    
-    public PhysicalFile(String path, Permissions mode) throws IOException {
-        if (mode == Permissions.NONE) file = null;
-        else file = new RandomAccessFile(path, mode.readMode);
+    public PhysicalFile(String path, Mode mode) throws FileNotFoundException {
+        if (mode == Mode.NONE) file = null;
+        else try { file = new RandomAccessFile(path, mode.name); }
+        catch (FileNotFoundException e) { throw new FilesystemException(filename, FSCode.DOESNT_EXIST); }

        perms = mode;
    }
--- a/src/me/topchetoeu/jscript/filesystem/PhysicalFilesystem.java
+++ b/src/me/topchetoeu/jscript/filesystem/PhysicalFilesystem.java
@@ -1,74 +1,74 @@
 package me.topchetoeu.jscript.filesystem;

+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.nio.file.Path;

+import me.topchetoeu.jscript.filesystem.FilesystemException.FSCode;
+
 public class PhysicalFilesystem implements Filesystem {
    public final Path root;

-    private Permissions getPerms(Path path) {
-        var file = path.toFile();
-        if (!path.startsWith(root)) return Permissions.NONE;
-        if (file.canRead() && file.canWrite()) return Permissions.READ_WRITE;
-        if (file.canRead()) return Permissions.READ;
-
-        return Permissions.NONE;
-    }
    private Path getPath(String name) {
-        return root.resolve(name);
+        return root.resolve(name.replace("\\", "/")).normalize();
+    }
+
+    private void checkMode(Path path, Mode mode) {
+        if (!path.startsWith(root)) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_R);
+        if (mode.readable && !path.toFile().canRead()) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_R);
+        if (mode.writable && !path.toFile().canWrite()) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_RW);
    }

    @Override
-    public File open(String path) throws IOException, InterruptedException {
-        var _path = root.resolve(path);
-
-        var perms = getPerms(_path);
-        if (perms == Permissions.NONE) return InaccessibleFile.INSTANCE;
-
+    public File open(String path, Mode perms) {
+        var _path = getPath(path);
        var f = _path.toFile();

-        if (f.isDirectory()) {
-            var res = new StringBuilder();
+        checkMode(_path, perms);

-            for (var child : f.listFiles()) res.append(child.toString()).append('\n');

-            return new MemoryFile(res.toString().getBytes(), Permissions.READ);
+        if (f.isDirectory()) return MemoryFile.fromFileList(path, f.listFiles());
+        else try { return new PhysicalFile(path, perms); }
+        catch (FileNotFoundException e) { throw new FilesystemException(_path.toString(), FSCode.DOESNT_EXIST); }
+    }
+
+    @Override
+    public void create(String path, EntryType type) {
+        var _path = getPath(path);
+        var f = _path.toFile();
+
+        switch (type) {
+            case FILE:
+                try {
+                    if (!f.createNewFile()) throw new FilesystemException(_path.toString(), FSCode.ALREADY_EXISTS);
+                    else break;
+                } 
+                catch (IOException e) { throw new FilesystemException(_path.toString(), FSCode.NO_PERMISSIONS_RW); }
+            case FOLDER:
+                if (!f.mkdir()) throw new FilesystemException(_path.toString(), FSCode.ALREADY_EXISTS);
+                else break;
+            case NONE:
+            default:
+                if (!f.delete()) throw new FilesystemException(_path.toString(), FSCode.DOESNT_EXIST);
+                else break;
        }
-        else return new PhysicalFile(path, perms);
    }

    @Override
-    public boolean mkdir(String path) throws IOException, InterruptedException {
+    public FileStat stat(String path) {
        var _path = getPath(path);
-        var perms = getPerms(_path);
        var f = _path.toFile();

-        if (!perms.writable) return false;
-        else return f.mkdir();
-    }
+        if (!f.exists()) throw new FilesystemException(_path.toString(), FSCode.DOESNT_EXIST);
+        checkMode(_path, Mode.READ);

-    @Override
-    public EntryType type(String path) throws IOException, InterruptedException {
-        var _path = getPath(path);
-        var perms = getPerms(_path);
-        var f = _path.toFile();
-
-        if (perms == Permissions.NONE) return EntryType.NONE;
-        else if (f.isFile()) return EntryType.FILE;
-        else return EntryType.FOLDER;
-    }
-
-    @Override
-    public boolean rm(String path) throws IOException, InterruptedException {
-        var _path = getPath(path);
-        var perms = getPerms(_path);
-        var f = _path.toFile();
-
-        if (!perms.writable) return false;
-        else return f.delete();
+        return new FileStat(
+            f.canWrite() ? Mode.READ_WRITE : Mode.READ,
+            f.isFile() ? EntryType.FILE : EntryType.FOLDER
+        );
    }

    public PhysicalFilesystem(Path root) {
-        this.root = root;
+        this.root = root.toAbsolutePath().normalize();
    }
 }
--- a/src/me/topchetoeu/jscript/filesystem/RootFilesystem.java
+++ b/src/me/topchetoeu/jscript/filesystem/RootFilesystem.java
@@ -0,0 +1,57 @@
+package me.topchetoeu.jscript.filesystem;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.filesystem.FilesystemException.FSCode;
+import me.topchetoeu.jscript.permissions.PermissionsProvider;
+
+public class RootFilesystem implements Filesystem {
+    public final Map<String, Filesystem> protocols = new HashMap<>();
+    public final PermissionsProvider perms;
+
+    private boolean canRead(String _path) {
+        return perms.hasPermission("jscript.file.read:" + _path, '/');
+    }
+    private boolean canWrite(String _path) {
+        return perms.hasPermission("jscript.file.write:" + _path, '/');
+    }
+
+    private void modeAllowed(String _path, Mode mode) throws FilesystemException {
+        if (mode.readable && perms != null && !canRead(_path)) throw new FilesystemException(_path, FSCode.NO_PERMISSIONS_R);
+        if (mode.writable && perms != null && !canWrite(_path)) throw new FilesystemException(_path, FSCode.NO_PERMISSIONS_RW);
+    }
+
+    @Override public File open(String path, Mode perms) throws FilesystemException {
+        var filename = Filename.parse(path);
+        var protocol = protocols.get(filename.protocol);
+        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
+        modeAllowed(filename.toString(), perms);
+
+        try { return protocol.open(filename.path, perms); }
+        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+    }
+    @Override public void create(String path, EntryType type) throws FilesystemException {
+        var filename = Filename.parse(path);
+        var protocol = protocols.get(filename.protocol);
+        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
+        modeAllowed(filename.toString(), Mode.READ_WRITE);
+
+        try { protocol.create(filename.path, type); }
+        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+    }
+    @Override public FileStat stat(String path) throws FilesystemException {
+        var filename = Filename.parse(path);
+        var protocol = protocols.get(filename.protocol);
+        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
+        modeAllowed(filename.toString(), Mode.READ);
+
+        try { return protocol.stat(path); }
+        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+    }
+
+    public RootFilesystem(PermissionsProvider perms) {
+        this.perms = perms;
+    }
+}
--- a/src/me/topchetoeu/jscript/interop/NativeWrapperProvider.java
+++ b/src/me/topchetoeu/jscript/interop/NativeWrapperProvider.java
@@ -9,10 +9,12 @@ import me.topchetoeu.jscript.engine.values.FunctionValue;
 import me.topchetoeu.jscript.engine.values.NativeFunction;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.exceptions.UncheckedException;

 public class NativeWrapperProvider implements WrappersProvider {
    private final HashMap<Class<?>, FunctionValue> constructors = new HashMap<>();
    private final HashMap<Class<?>, ObjectValue> prototypes = new HashMap<>();
+    private final HashMap<Class<?>, ObjectValue> namespaces = new HashMap<>();
    private final Environment env;

    private static void applyMethods(Environment env, boolean member, ObjectValue target, Class<?> clazz) {
@@ -31,7 +33,7 @@ public class NativeWrapperProvider implements WrappersProvider {

                var val = target.values.get(name);

-                if (!(val instanceof OverloadFunction)) target.defineProperty(null, name, val = new OverloadFunction(name.toString()));
+                if (!(val instanceof OverloadFunction)) target.defineProperty(null, name, val = new OverloadFunction(name.toString()), true, true, false);

                ((OverloadFunction)val).add(Overload.fromMethod(method, nat.thisArg()));
            }
@@ -51,7 +53,7 @@ public class NativeWrapperProvider implements WrappersProvider {
                    else getter = new OverloadFunction("get " + name);

                    getter.add(Overload.fromMethod(method, get.thisArg()));
-                    target.defineProperty(null, name, getter, setter, true, true);
+                    target.defineProperty(null, name, getter, setter, true, false);
                }
                if (set != null) {
                    if (set.thisArg() && !member || !set.thisArg() && !memberMatch) continue;
@@ -68,7 +70,7 @@ public class NativeWrapperProvider implements WrappersProvider {
                    else setter = new OverloadFunction("set " + name);

                    setter.add(Overload.fromMethod(method, set.thisArg()));
-                    target.defineProperty(null, name, getter, setter, true, true);
+                    target.defineProperty(null, name, getter, setter, true, false);
                }
            }
        }
@@ -106,6 +108,12 @@ public class NativeWrapperProvider implements WrappersProvider {
        }
    }

+    public static String getName(Class<?> clazz) {
+        var classNat = clazz.getAnnotation(Native.class);
+        if (classNat != null && !classNat.value().trim().equals("")) return classNat.value().trim();
+        else return clazz.getSimpleName();
+    }
+
    /**
     * Generates a prototype for the given class.
     * The returned object will have appropriate wrappers for all instance members.
@@ -115,11 +123,13 @@ public class NativeWrapperProvider implements WrappersProvider {
    public static ObjectValue makeProto(Environment ctx, Class<?> clazz) {
        var res = new ObjectValue();

+        res.defineProperty(null, ctx.symbol("Symbol.typeName"), getName(clazz));
+
        for (var overload : clazz.getDeclaredMethods()) {
            var init = overload.getAnnotation(NativeInit.class);
            if (init == null || init.value() != InitType.PROTOTYPE) continue;
            try { overload.invoke(null, ctx, res); }
-            catch (ReflectiveOperationException e) { e.printStackTrace(); }
+            catch (Throwable e) { throw new UncheckedException(e); }
        }

        applyMethods(ctx, true, res, clazz);
@@ -135,7 +145,7 @@ public class NativeWrapperProvider implements WrappersProvider {
     * @param clazz The class for which a constructor should be generated
     */
    public static FunctionValue makeConstructor(Environment ctx, Class<?> clazz) {
-        FunctionValue func = new OverloadFunction(clazz.getName());
+        FunctionValue func = new OverloadFunction(getName(clazz));

        for (var overload : clazz.getDeclaredConstructors()) {
            var nat = overload.getAnnotation(Native.class);
@@ -151,7 +161,7 @@ public class NativeWrapperProvider implements WrappersProvider {
            var init = overload.getAnnotation(NativeInit.class);
            if (init == null || init.value() != InitType.CONSTRUCTOR) continue;
            try { overload.invoke(null, ctx, func); }
-            catch (ReflectiveOperationException e) { e.printStackTrace(); }
+            catch (Throwable e) { throw new UncheckedException(e); }
        }

        if (((OverloadFunction)func).overloads.size() == 0) {
@@ -179,7 +189,7 @@ public class NativeWrapperProvider implements WrappersProvider {
            var init = overload.getAnnotation(NativeInit.class);
            if (init == null || init.value() != InitType.NAMESPACE) continue;
            try { overload.invoke(null, ctx, res); }
-            catch (ReflectiveOperationException e) { e.printStackTrace(); }
+            catch (Throwable e) { throw new UncheckedException(e); }
        }

        applyMethods(ctx, false, res, clazz);
@@ -209,8 +219,8 @@ public class NativeWrapperProvider implements WrappersProvider {
        if (constr == null) constr = makeConstructor(env, clazz);
        if (proto == null) proto = makeProto(env, clazz);

-        proto.values.put("constructor", constr);
-        constr.values.put("prototype", proto);
+        proto.defineProperty(null, "constructor", constr, true, false, false);
+        constr.defineProperty(null, "prototype", proto, true, false, false);

        prototypes.put(clazz, proto);
        constructors.put(clazz, constr);
@@ -229,11 +239,20 @@ public class NativeWrapperProvider implements WrappersProvider {
        initType(clazz, constructors.get(clazz), prototypes.get(clazz));
        return prototypes.get(clazz);
    }
+    public ObjectValue getNamespace(Class<?> clazz) {
+        if (!namespaces.containsKey(clazz)) namespaces.put(clazz, makeNamespace(env, clazz));
+        return namespaces.get(clazz);
+    }
    public FunctionValue getConstr(Class<?> clazz) {
        initType(clazz, constructors.get(clazz), prototypes.get(clazz));
        return constructors.get(clazz);
    }

+    @Override
+    public WrappersProvider fork(Environment env) {
+        return new NativeWrapperProvider(env);
+    }
+
    public void setProto(Class<?> clazz, ObjectValue value) {
        prototypes.put(clazz, value);
    }
@@ -241,7 +260,27 @@ public class NativeWrapperProvider implements WrappersProvider {
        constructors.put(clazz, value);
    }

+    private void initError() {
+        var proto = new ObjectValue();
+        proto.defineProperty(null, "message", new NativeFunction("message", (ctx, thisArg, args) -> {
+            if (thisArg instanceof Throwable) return ((Throwable)thisArg).getMessage();
+            else return null;
+        }));
+        proto.defineProperty(null, "name", new NativeFunction("name", (ctx, thisArg, args) -> getName(thisArg.getClass())));
+
+        var constr = makeConstructor(null, Throwable.class);
+        proto.defineProperty(null, "constructor", constr, true, false, false);
+        constr.defineProperty(null, "prototype", proto, true, false, false);
+
+        proto.setPrototype(null, getProto(Object.class));
+        constr.setPrototype(null, getConstr(Object.class));
+
+        setProto(Throwable.class, proto);
+        setConstr(Throwable.class, constr);
+    }
+
    public NativeWrapperProvider(Environment env) {
        this.env = env;
+        initError();
    }
 }
--- a/src/me/topchetoeu/jscript/interop/Overload.java
+++ b/src/me/topchetoeu/jscript/interop/Overload.java
@@ -9,10 +9,7 @@ import me.topchetoeu.jscript.engine.Context;

 public class Overload {
    public static interface OverloadRunner {
-        Object run(Context ctx, Object thisArg, Object[] args) throws
-            InterruptedException,
-            ReflectiveOperationException,
-            IllegalArgumentException;
+        Object run(Context ctx, Object thisArg, Object[] args) throws ReflectiveOperationException, IllegalArgumentException;
    }

    public final OverloadRunner runner;
@@ -47,9 +44,11 @@ public class Overload {
    public static Overload setterFromField(Field field) {
        if (Modifier.isFinal(field.getModifiers())) return null;
        return new Overload(
-            (ctx, th, args) -> { field.set(th, args[0]); return null; }, false, false,
+            (ctx, th, args) -> {
+                field.set(th, args[0]); return null;
+            }, false, false,
            Modifier.isStatic(field.getModifiers()) ? null : field.getDeclaringClass(),
-            new Class[0]
+            new Class[] { field.getType() }
        );
    }

--- a/src/me/topchetoeu/jscript/interop/OverloadFunction.java
+++ b/src/me/topchetoeu/jscript/interop/OverloadFunction.java
@@ -8,14 +8,16 @@ import java.util.List;
 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.engine.Context;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
+import me.topchetoeu.jscript.engine.values.NativeWrapper;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.exceptions.ConvertException;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.exceptions.InterruptException;

 public class OverloadFunction extends FunctionValue {
    public final List<Overload> overloads = new ArrayList<>();

-    public Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
+    public Object call(Context ctx, Object thisArg, Object ...args) {
        loop: for (var overload : overloads) {
            Object[] newArgs = new Object[overload.params.length];

@@ -76,29 +78,33 @@ public class OverloadFunction extends FunctionValue {
            try {
                return Values.normalize(ctx, overload.runner.run(ctx, _this, newArgs));
            }
-            catch (InstantiationException e) {
-                throw EngineException.ofError("The class may not be instantiated.");
-            }
-            catch (IllegalAccessException | IllegalArgumentException e) {
-                continue;
-            }
+            catch (InstantiationException e) { throw EngineException.ofError("The class may not be instantiated."); }
+            catch (IllegalAccessException | IllegalArgumentException e) { continue; }
            catch (InvocationTargetException e) {
-                var loc = new Location(0, 0, "<internal>");
+                var loc = Location.INTERNAL;
                if (e.getTargetException() instanceof EngineException) {
                    throw ((EngineException)e.getTargetException()).add(name, loc);
                }
                else if (e.getTargetException() instanceof NullPointerException) {
+                    e.printStackTrace();
                    throw EngineException.ofType("Unexpected value of 'undefined'.").add(name, loc);
                }
+                else if (e.getTargetException() instanceof InterruptException || e.getTargetException() instanceof InterruptedException) {
+                    throw new InterruptException();
+                }
                else {
-                    throw EngineException.ofError(e.getTargetException().getMessage()).add(name, loc);
+                    var target = e.getTargetException();
+                    var targetClass = target.getClass();
+                    var err = new NativeWrapper(e.getTargetException());
+
+                    err.defineProperty(ctx, "message", target.getMessage());
+                    err.defineProperty(ctx, "name", NativeWrapperProvider.getName(targetClass));
+
+                    throw new EngineException(err).add(name, loc);
                }
            }
            catch (ReflectiveOperationException e) {
-                throw EngineException.ofError(e.getMessage()).add(name, new Location(0, 0, "<internal>"));
-            }
-            catch (Exception e) {
-                throw e;
+                throw EngineException.ofError(e.getMessage()).add(name, Location.INTERNAL);
            }
        }

--- a/src/me/topchetoeu/jscript/js/bootstrap.js
+++ b/src/me/topchetoeu/jscript/js/bootstrap.js
@@ -1,86 +1,111 @@
-// TODO: load this in java
-var ts = require('./ts');
-log("Loaded typescript!");
+(function (_arguments) {
+    var ts = _arguments[0];
+    var src = '', version = 0;
+    var lib = _arguments[2].concat([
+        'declare const exit: never; declare const go: any;',
+        'declare function getTsDeclarations(): string[];'
+    ]).join('');
+    var libSnapshot = ts.ScriptSnapshot.fromString(lib);
+    var environments = {};
+    var declSnapshots = [];

-var src = '', lib = libs.concat([ 'declare const exit: never;' ]).join(''), decls = '', version = 0;
-var libSnapshot = ts.ScriptSnapshot.fromString(lib);
+    var settings = {
+        outDir: "/out",
+        declarationDir: "/out",
+        target: ts.ScriptTarget.ES5,
+        lib: [ ],
+        module: ts.ModuleKind.None,
+        declaration: true,
+        stripInternal: true,
+        downlevelIteration: true,
+        forceConsistentCasingInFileNames: true,
+        experimentalDecorators: true,
+        strict: true,
+    };

-var settings = {
-    outDir: "/out",
-    declarationDir: "/out",
-    target: ts.ScriptTarget.ES5,
-    lib: [ ],
-    module: ts.ModuleKind.None,
-    declaration: true,
-    stripInternal: true,
-    downlevelIteration: true,
-    forceConsistentCasingInFileNames: true,
-    experimentalDecorators: true,
-    strict: true,
-};
+    var reg = ts.createDocumentRegistry();
+    var service = ts.createLanguageService({
+        getCurrentDirectory: function() { return "/"; },
+        getDefaultLibFileName: function() { return "/lib.d.ts"; },
+        getScriptFileNames: function() {
+            var res = [ "/src.ts", "/lib.d.ts" ];
+            for (var i = 0; i < declSnapshots.length; i++) res.push("/glob." + (i + 1) + ".d.ts");
+            return res;
+        },
+        getCompilationSettings: function () { return settings; },
+        fileExists: function(filename) { return filename === "/lib.d.ts" || filename === "/src.ts" || filename === "/glob.d.ts"; },

-var reg = ts.createDocumentRegistry();
-var service = ts.createLanguageService({
-    getCurrentDirectory: function() { return "/"; },
-    getDefaultLibFileName: function() { return "/lib_.d.ts"; },
-    getScriptFileNames: function() { return [ "/src.ts", "/lib.d.ts", "/glob.d.ts" ]; },
-    getCompilationSettings: function () { return settings; },
-    fileExists: function(filename) { return filename === "/lib.d.ts" || filename === "/src.ts" || filename === "/glob.d.ts"; },
+        getScriptSnapshot: function(filename) {
+            if (filename === "/lib.d.ts") return libSnapshot;
+            if (filename === "/src.ts") return ts.ScriptSnapshot.fromString(src);

-    getScriptSnapshot: function(filename) {
-        if (filename === "/lib.d.ts") return libSnapshot;
-        if (filename === "/src.ts") return ts.ScriptSnapshot.fromString(src);
-        if (filename === "/glob.d.ts") return ts.ScriptSnapshot.fromString(decls);
-        throw new Error("File '" + filename + "' doesn't exist.");
-    },
-    getScriptVersion: function (filename) {
-        if (filename === "/lib.d.ts") return 0;
-        else return version;
-    },
-}, reg);
-
-service.getEmitOutput('/lib.d.ts');
-log('Loaded libraries!');
-
-function compile(filename, code) {
-    src = code, version++;
-
-    var emit = service.getEmitOutput("/src.ts");
-
-    var diagnostics = []
-        .concat(service.getCompilerOptionsDiagnostics())
-        .concat(service.getSyntacticDiagnostics("/src.ts"))
-        .concat(service.getSemanticDiagnostics("/src.ts"))
-        .map(function (diagnostic) {
-            var message = ts.flattenDiagnosticMessageText(diagnostic.messageText, "\n");
-            if (diagnostic.file) {
-                var pos = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
-                var file = diagnostic.file.fileName.substring(1);
-                if (file === "src.ts") file = filename;
-                return file + ":" + (pos.line + 1) + ":" + (pos.character + 1) + ": " + message;
+            var index = /\/glob\.(\d+)\.d\.ts/g.exec(filename);
+            if (index && index[1] && (index = Number(index[1])) && index > 0 && index <= declSnapshots.length) {
+                return declSnapshots[index - 1];
            }
-            else return "Error: " + message;
-        });

-    if (diagnostics.length > 0) {
-        throw new SyntaxError(diagnostics.join('\n'));
+            throw new Error("File '" + filename + "' doesn't exist.");
+        },
+        getScriptVersion: function (filename) {
+            if (filename === "/lib.d.ts" || filename.startsWith("/glob.")) return 0;
+            else return version;
+        },
+    }, reg);
+
+    service.getEmitOutput("/lib.d.ts");
+    log("Loaded libraries!");
+
+    function compile(code, filename, env) {
+        src = code;
+        version++;
+
+        if (!environments[env.id]) environments[env.id] = []
+        declSnapshots = environments[env.id];
+        var emit = service.getEmitOutput("/src.ts");
+
+        var diagnostics = []
+            .concat(service.getCompilerOptionsDiagnostics())
+            .concat(service.getSyntacticDiagnostics("/src.ts"))
+            .concat(service.getSemanticDiagnostics("/src.ts"))
+            .map(function (diagnostic) {
+                var message = ts.flattenDiagnosticMessageText(diagnostic.messageText, "\n");
+                if (diagnostic.file) {
+                    var pos = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
+                    var file = diagnostic.file.fileName.substring(1);
+                    if (file === "src.ts") file = filename;
+                    return file + ":" + (pos.line + 1) + ":" + (pos.character + 1) + ": " + message;
+                }
+                else return message;
+            });
+
+        if (diagnostics.length > 0) {
+            throw new SyntaxError(diagnostics.join("\n"));
+        }
+
+        var result = emit.outputFiles[0].text;
+        var declaration = emit.outputFiles[1].text;
+        
+
+        return {
+            source: result,
+            runner: function(func) {
+                return function() {
+                    var val = func.apply(this, arguments);
+                    if (declaration !== '') {
+                        declSnapshots.push(ts.ScriptSnapshot.fromString(declaration));
+                    }
+                    return val;
+                }
+            }
+        };
    }

-    return {
-        result: emit.outputFiles[0].text,
-        declaration: emit.outputFiles[1].text
-    };
-}
-
-init(function (filename, code) {
-    var res = compile(filename, code);
-
-    return [
-        res.result,
-        function(func, th, args) {
-            var val = func.apply(th, args);
-            decls += res.declaration;
-            return val;
+    function apply(env) {
+        env.compile = compile;
+        env.global.getTsDeclarations = function() {
+            return environments[env.id];
        }
-    ];
-});
+    }
+
+    apply(_arguments[1]);
+})(arguments);
--- a/src/me/topchetoeu/jscript/js/lib.d.ts
+++ b/src/me/topchetoeu/jscript/js/lib.d.ts
@@ -482,6 +482,35 @@ interface PromiseConstructor {
    allSettled<T extends any[]>(...promises: T): Promise<[...{ [P in keyof T]: PromiseResult<Awaited<T[P]>>}]>;
 }

+interface FileStat {
+    type: 'file' | 'folder';
+    mode: 'r' | 'rw';
+}
+interface File {
+    readonly pointer: Promise<number>;
+    readonly length: Promise<number>;
+    readonly mode: Promise<'' | 'r' | 'rw'>;
+
+    read(n: number): Promise<number[]>;
+    write(buff: number[]): Promise<void>;
+    close(): Promise<void>;
+    setPointer(val: number): Promise<void>;
+}
+interface Filesystem {
+    open(path: string, mode: 'r' | 'rw'): Promise<File>;
+    ls(path: string): AsyncIterableIterator<string>;
+    mkdir(path: string): Promise<void>;
+    mkfile(path: string): Promise<void>;
+    rm(path: string, recursive?: boolean): Promise<void>;
+    stat(path: string): Promise<FileStat>;
+    exists(path: string): Promise<boolean>;
+}
+
+interface Encoding {
+    encode(val: string): number[];
+    decode(val: number[]): string;
+}
+
 declare var String: StringConstructor;
 //@ts-ignore
 declare const arguments: IArguments;
@@ -508,6 +537,8 @@ declare var Object: ObjectConstructor;
 declare var Symbol: SymbolConstructor;
 declare var Promise: PromiseConstructor;
 declare var Math: MathObject;
+declare var Encoding: Encoding;
+declare var Filesystem: Filesystem;

 declare var Error: ErrorConstructor;
 declare var RangeError: RangeErrorConstructor;
--- a/src/me/topchetoeu/jscript/js/ts.js
+++ b/src/me/topchetoeu/jscript/js/ts.js
--- a/src/me/topchetoeu/jscript/json/JSON.java
+++ b/src/me/topchetoeu/jscript/json/JSON.java
@@ -1,8 +1,15 @@
 package me.topchetoeu.jscript.json;

+import java.util.HashSet;
 import java.util.List;
 import java.util.stream.Collectors;

+import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.values.ArrayValue;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.exceptions.SyntaxException;
 import me.topchetoeu.jscript.parsing.Operator;
 import me.topchetoeu.jscript.parsing.ParseRes;
@@ -10,20 +17,80 @@ import me.topchetoeu.jscript.parsing.Parsing;
 import me.topchetoeu.jscript.parsing.Token;

 public class JSON {
+    public static Object toJs(JSONElement val) {
+        if (val.isBoolean()) return val.bool();
+        if (val.isString()) return val.string();
+        if (val.isNumber()) return val.number();
+        if (val.isList()) return ArrayValue.of(null, val.list().stream().map(JSON::toJs).collect(Collectors.toList()));
+        if (val.isMap()) {
+            var res = new ObjectValue();
+            for (var el : val.map().entrySet()) {
+                res.defineProperty(null, el.getKey(), toJs(el.getValue()));
+            }
+            return res;
+        }
+        if (val.isNull()) return Values.NULL;
+        return null;
+    }
+    private static JSONElement fromJs(Context ctx, Object val, HashSet<Object> prev) {
+        if (val instanceof Boolean) return JSONElement.bool((boolean)val);
+        if (val instanceof Number) return JSONElement.number(((Number)val).doubleValue());
+        if (val instanceof String) return JSONElement.string((String)val);
+        if (val == Values.NULL) return JSONElement.NULL;
+        if (val instanceof ObjectValue) {
+            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
+            prev.add(val);
+
+            var res = new JSONMap();
+
+            for (var el : ((ObjectValue)val).keys(false)) {
+                var jsonEl = fromJs(ctx, ((ObjectValue)val).getMember(ctx, el), prev);
+                if (jsonEl == null) continue;
+                if (el instanceof String || el instanceof Number) res.put(el.toString(), jsonEl);
+            }
+
+            prev.remove(val);
+            return JSONElement.of(res);
+        }
+        if (val instanceof ArrayValue) {
+            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
+            prev.add(val);
+
+            var res = new JSONList();
+
+            for (var el : ((ArrayValue)val).toArray()) {
+                var jsonEl = fromJs(ctx, el, prev);
+                if (jsonEl == null) jsonEl = JSONElement.NULL;
+                res.add(jsonEl);
+            }
+
+            prev.remove(val);
+            return JSONElement.of(res);
+        }
+        if (val == null) return null;
+        return null;
+    }
+    public static JSONElement fromJs(Context ctx, Object val) {
+        return fromJs(ctx, val, new HashSet<>());
+    }
+
    public static ParseRes<String> parseIdentifier(List<Token> tokens, int i) {
        return Parsing.parseIdentifier(tokens, i);
    }
-    public static ParseRes<String> parseString(String filename, List<Token> tokens, int i) {
+    public static ParseRes<String> parseString(Filename filename, List<Token> tokens, int i) {
        var res = Parsing.parseString(filename, tokens, i);
        if (res.isSuccess()) return ParseRes.res((String)res.result.value, res.n);
        else return res.transform();
    }
-    public static ParseRes<Double> parseNumber(String filename, List<Token> tokens, int i) {
+    public static ParseRes<Double> parseNumber(Filename filename, List<Token> tokens, int i) {
+        var minus = Parsing.isOperator(tokens, i, Operator.SUBTRACT);
+        if (minus) i++;
+
        var res = Parsing.parseNumber(filename, tokens, i);
-        if (res.isSuccess()) return ParseRes.res((Double)res.result.value, res.n);
+        if (res.isSuccess()) return ParseRes.res((minus ? -1 : 1) * (Double)res.result.value, res.n + (minus ? 1 : 0));
        else return res.transform();
    }
-    public static ParseRes<Boolean> parseBool(String filename, List<Token> tokens, int i) {
+    public static ParseRes<Boolean> parseBool(Filename filename, List<Token> tokens, int i) {
        var id = parseIdentifier(tokens, i);

        if (!id.isSuccess()) return ParseRes.failed();
@@ -32,7 +99,7 @@ public class JSON {
        else return ParseRes.failed();
    }

-    public static ParseRes<?> parseValue(String filename, List<Token> tokens, int i) {
+    public static ParseRes<?> parseValue(Filename filename, List<Token> tokens, int i) {
        return ParseRes.any(
            parseString(filename, tokens, i),
            parseNumber(filename, tokens, i),
@@ -42,7 +109,7 @@ public class JSON {
        );
    }

-    public static ParseRes<JSONMap> parseMap(String filename, List<Token> tokens, int i) {
+    public static ParseRes<JSONMap> parseMap(Filename filename, List<Token> tokens, int i) {
        int n = 0;
        if (!Parsing.isOperator(tokens, i + n++, Operator.BRACE_OPEN)) return ParseRes.failed();

@@ -82,7 +149,7 @@ public class JSON {

        return ParseRes.res(values, n);
    }
-    public static ParseRes<JSONList> parseList(String filename, List<Token> tokens, int i) {
+    public static ParseRes<JSONList> parseList(Filename filename, List<Token> tokens, int i) {
        int n = 0;
        if (!Parsing.isOperator(tokens, i + n++, Operator.BRACKET_OPEN)) return ParseRes.failed();

@@ -109,7 +176,8 @@ public class JSON {

        return ParseRes.res(values, n);
    }
-    public static JSONElement parse(String filename, String raw) {
+    public static JSONElement parse(Filename filename, String raw) {
+        if (filename == null) filename = new Filename("jscript", "json");
        var res = parseValue(filename, Parsing.tokenize(filename, raw), 0);
        if (res.isFailed()) throw new SyntaxException(null, "Invalid JSON given.");
        else if (res.isError()) throw new SyntaxException(null, res.error);
@@ -120,7 +188,28 @@ public class JSON {
        if (el.isNumber()) return Double.toString(el.number());
        if (el.isBoolean()) return el.bool() ? "true" : "false";
        if (el.isNull()) return "null";
-        if (el.isString()) return "\"" + el.string().replace("\\", "\\\\").replace("\"", "\\\"") + "\"";
+        if (el.isString()) {
+            var res = new StringBuilder("\"");
+            var alphabet = "0123456789ABCDEF".toCharArray();
+
+            for (var c : el.string().toCharArray()) {
+                if (c < 32 || c >= 127) {
+                    res
+                        .append("\\u")
+                        .append(alphabet[(c >> 12) & 0xF])
+                        .append(alphabet[(c >> 8) & 0xF])
+                        .append(alphabet[(c >> 4) & 0xF])
+                        .append(alphabet[(c >> 0) & 0xF]);
+                }
+                else if (c == '\\')
+                    res.append("\\\\");
+                else if (c == '"')
+                    res.append("\\\"");
+                else res.append(c);
+            }
+
+            return res.append('"').toString();
+        }
        if (el.isList()) {
            var res = new StringBuilder().append("[");
            for (int i = 0; i < el.list().size(); i++) {
--- a/src/me/topchetoeu/jscript/json/JSONElement.java
+++ b/src/me/topchetoeu/jscript/json/JSONElement.java
@@ -65,10 +65,22 @@ public class JSONElement {
        return (double)value;
    }
    public boolean bool() {
-        if (!isNumber()) throw new IllegalStateException("Element is not a boolean.");
+        if (!isBoolean()) throw new IllegalStateException("Element is not a boolean.");
        return (boolean)value;
    }

+    @Override
+    public String toString() {
+        if (isMap()) return "{...}";
+        if (isList()) return "[...]";
+        if (isString()) return (String)value;
+        if (isString()) return (String)value;
+        if (isNumber()) return (double)value + "";
+        if (isBoolean()) return (boolean)value + "";
+        if (isNull()) return "null";
+        return "";
+    }
+
    private JSONElement(Type type, Object val) {
        this.type = type;
        this.value = val;
--- a/src/me/topchetoeu/jscript/json/JSONList.java
+++ b/src/me/topchetoeu/jscript/json/JSONList.java
@@ -10,6 +10,9 @@ public class JSONList extends ArrayList<JSONElement> {
    public JSONList(JSONElement ...els) {
        super(List.of(els));
    }
+    public JSONList(Collection<JSONElement> els) {
+        super(els);
+    }

    public JSONList addNull() { this.add(JSONElement.NULL); return this; }
    public JSONList add(String val) { this.add(JSONElement.of(val)); return this; }
@@ -17,5 +20,7 @@ public class JSONList extends ArrayList<JSONElement> {
    public JSONList add(boolean val) { this.add(JSONElement.of(val)); return this; }
    public JSONList add(Map<String, JSONElement> val) { this.add(JSONElement.of(val)); return this; }
    public JSONList add(Collection<JSONElement> val) { this.add(JSONElement.of(val)); return this; }
+    public JSONList add(JSONMap val) { this.add(JSONElement.of(val)); return this; }
+    public JSONList add(JSONList val) { this.add(JSONElement.of(val)); return this; }

 }
--- a/src/me/topchetoeu/jscript/json/JSONMap.java
+++ b/src/me/topchetoeu/jscript/json/JSONMap.java
@@ -51,7 +51,7 @@ public class JSONMap implements Map<String, JSONElement> {

    public JSONMap map(String path) {
        var el = get(path);
-        if (el == null) throw new IllegalStateException(String.format("'%s' doesn't exist.", path));
+        if (el == null) throw new RuntimeException(String.format("'%s' doesn't exist.", path));
        return el.map();
    }
    public JSONMap map(String path, JSONMap defaultVal) {
@@ -63,7 +63,7 @@ public class JSONMap implements Map<String, JSONElement> {

    public JSONList list(String path) {
        var el = get(path);
-        if (el == null) throw new IllegalStateException(String.format("'%s' doesn't exist.", path));
+        if (el == null) throw new RuntimeException(String.format("'%s' doesn't exist.", path));
        return el.list();
    }
    public JSONList list(String path, JSONList defaultVal) {
@@ -75,7 +75,7 @@ public class JSONMap implements Map<String, JSONElement> {

    public String string(String path) {
        var el = get(path);
-        if (el == null) throw new IllegalStateException(String.format("'%s' doesn't exist.", path));
+        if (el == null) throw new RuntimeException(String.format("'%s' doesn't exist.", path));
        return el.string();
    }
    public String string(String path, String defaultVal) {
@@ -87,7 +87,7 @@ public class JSONMap implements Map<String, JSONElement> {

    public double number(String path) {
        var el = get(path);
-        if (el == null) throw new IllegalStateException(String.format("'%s' doesn't exist.", path));
+        if (el == null) throw new RuntimeException(String.format("'%s' doesn't exist.", path));
        return el.number();
    }
    public double number(String path, double defaultVal) {
@@ -99,7 +99,7 @@ public class JSONMap implements Map<String, JSONElement> {

    public boolean bool(String path) {
        var el = get(path);
-        if (el == null) throw new IllegalStateException(String.format("'%s' doesn't exist.", path));
+        if (el == null) throw new RuntimeException(String.format("'%s' doesn't exist.", path));
        return el.bool();
    }
    public boolean bool(String path, boolean defaultVal) {
--- a/src/me/topchetoeu/jscript/polyfills/ArrayPolyfill.java
+++ b/src/me/topchetoeu/jscript/polyfills/ArrayPolyfill.java
@@ -1,34 +1,32 @@
-package me.topchetoeu.jscript.polyfills;
+package me.topchetoeu.jscript.lib;

 import java.util.Iterator;
 import java.util.Stack;

 import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.Environment;
 import me.topchetoeu.jscript.engine.values.ArrayValue;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
+import me.topchetoeu.jscript.engine.values.NativeFunction;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.engine.values.Values;
-import me.topchetoeu.jscript.interop.InitType;
 import me.topchetoeu.jscript.interop.Native;
 import me.topchetoeu.jscript.interop.NativeConstructor;
 import me.topchetoeu.jscript.interop.NativeGetter;
-import me.topchetoeu.jscript.interop.NativeInit;
 import me.topchetoeu.jscript.interop.NativeSetter;

-public class ArrayPolyfill {
-    @NativeGetter(thisArg = true) public static int length(Context ctx, ArrayValue thisArg) throws InterruptedException {
+@Native("Array") public class ArrayLib {
+    @NativeGetter(thisArg = true) public static int length(Context ctx, ArrayValue thisArg) {
        return thisArg.size();
    }
-    @NativeSetter(thisArg = true) public static void length(Context ctx, ArrayValue thisArg, int len) throws InterruptedException {
+    @NativeSetter(thisArg = true) public static void length(Context ctx, ArrayValue thisArg, int len) {
        thisArg.setSize(len);
    }
    
-    @Native(thisArg = true) public static ObjectValue values(Context ctx, ArrayValue thisArg) throws InterruptedException {
-        return Values.fromJavaIterable(ctx, thisArg);
+    @Native(thisArg = true) public static ObjectValue values(Context ctx, ArrayValue thisArg) {
+        return Values.toJSIterator(ctx, thisArg);
    }
-    @Native(thisArg = true) public static ObjectValue keys(Context ctx, ArrayValue thisArg) throws InterruptedException {
-        return Values.fromJavaIterable(ctx, () -> new Iterator<Object>() {
+    @Native(thisArg = true) public static ObjectValue keys(Context ctx, ArrayValue thisArg) {
+        return Values.toJSIterator(ctx, () -> new Iterator<Object>() {
            private int i = 0;

            @Override
@@ -42,8 +40,8 @@ public class ArrayPolyfill {
            }
        });
    }
-    @Native(thisArg = true) public static ObjectValue entries(Context ctx, ArrayValue thisArg) throws InterruptedException {
-        return Values.fromJavaIterable(ctx, () -> new Iterator<Object>() {
+    @Native(thisArg = true) public static ObjectValue entries(Context ctx, ArrayValue thisArg) {
+        return Values.toJSIterator(ctx, () -> new Iterator<Object>() {
            private int i = 0;

            @Override
@@ -59,17 +57,17 @@ public class ArrayPolyfill {
    }

    @Native(value = "@@Symbol.iterator", thisArg = true)
-    public static ObjectValue iterator(Context ctx, ArrayValue thisArg) throws InterruptedException {
+    public static ObjectValue iterator(Context ctx, ArrayValue thisArg) {
        return values(ctx, thisArg);
    }
    @Native(value = "@@Symbol.asyncIterator", thisArg = true)
-    public static ObjectValue asyncIterator(Context ctx, ArrayValue thisArg) throws InterruptedException {
+    public static ObjectValue asyncIterator(Context ctx, ArrayValue thisArg) {
        return values(ctx, thisArg);
    }

-    @Native(thisArg = true) public static ArrayValue concat(Context ctx, ArrayValue thisArg, Object ...others) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue concat(Context ctx, ArrayValue thisArg, Object ...others) {
        // TODO: Fully implement with non-array spreadable objects
-        var size = 0;
+        var size = thisArg.size();

        for (int i = 0; i < others.length; i++) {
            if (others[i] instanceof ArrayValue) size += ((ArrayValue)others[i]).size();
@@ -77,8 +75,9 @@ public class ArrayPolyfill {
        }

        var res = new ArrayValue(size);
+        thisArg.copyTo(ctx, res, 0, 0, thisArg.size());

-        for (int i = 0, j = 0; i < others.length; i++) {
+        for (int i = 0, j = thisArg.size(); i < others.length; i++) {
            if (others[i] instanceof ArrayValue) {
                int n = ((ArrayValue)others[i]).size();
                ((ArrayValue)others[i]).copyTo(ctx, res, 0, j, n);
@@ -92,24 +91,17 @@ public class ArrayPolyfill {
        return res;
    }

-    @Native(thisArg = true) public static void sort(Context ctx, ArrayValue arr, FunctionValue cmp) throws InterruptedException {
-        try {
-            arr.sort((a, b) -> {
-                try {
-                    var res = Values.toNumber(ctx, cmp.call(ctx, null, a, b));
-                    if (res < 0) return -1;
-                    if (res > 0) return 1;
-                    return 0;
-                }
-                catch (InterruptedException e) {
-                    throw new RuntimeException(e);
-                }
-            });
-        }
-        catch (RuntimeException e) {
-            if (e.getCause() instanceof InterruptedException) throw (InterruptedException)e.getCause();
-            else throw e;
-        }
+    @Native(thisArg = true) public static ArrayValue sort(Context ctx, ArrayValue arr, FunctionValue cmp) {
+        var defaultCmp = new NativeFunction("", (_ctx, thisArg, args) -> {
+            return Values.toString(ctx, args[0]).compareTo(Values.toString(ctx, args[1]));
+        });
+        arr.sort((a, b) -> {
+            var res = Values.toNumber(ctx, (cmp == null ? defaultCmp : cmp).call(ctx, null, a, b));
+            if (res < 0) return -1;
+            if (res > 0) return 1;
+            return 0;
+        });
+        return arr;
    }

    private static int normalizeI(int len, int i, boolean clamp) {
@@ -121,7 +113,7 @@ public class ArrayPolyfill {
        return i;
    }

-    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val, int start, int end) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val, int start, int end) {
        start = normalizeI(arr.size(), start, true);
        end = normalizeI(arr.size(), end, true);

@@ -131,21 +123,21 @@ public class ArrayPolyfill {

        return arr;
    }
-    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val, int start) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val, int start) {
        return fill(ctx, arr, val, start, arr.size());
    }
-    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue fill(Context ctx, ArrayValue arr, Object val) {
        return fill(ctx, arr, val, 0, arr.size());
    }

-    @Native(thisArg = true) public static boolean every(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static boolean every(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) {
        for (var i = 0; i < arr.size(); i++) {
            if (!Values.toBoolean(func.call(ctx, thisArg, arr.get(i), i, arr))) return false;
        }

        return true;
    }
-    @Native(thisArg = true) public static boolean some(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static boolean some(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) {
        for (var i = 0; i < arr.size(); i++) {
            if (Values.toBoolean(func.call(ctx, thisArg, arr.get(i), i, arr))) return true;
        }
@@ -153,7 +145,7 @@ public class ArrayPolyfill {
        return false;
    }

-    @Native(thisArg = true) public static ArrayValue filter(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue filter(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) {
        var res = new ArrayValue(arr.size());

        for (int i = 0, j = 0; i < arr.size(); i++) {
@@ -161,20 +153,51 @@ public class ArrayPolyfill {
        }
        return res;
    }
-    @Native(thisArg = true) public static ArrayValue map(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue map(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) {
        var res = new ArrayValue(arr.size());
        for (int i = 0, j = 0; i < arr.size(); i++) {
            if (arr.has(i)) res.set(ctx, j++, func.call(ctx, thisArg, arr.get(i), i, arr));
        }
        return res;
    }
-    @Native(thisArg = true) public static void forEach(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static void forEach(Context ctx, ArrayValue arr, FunctionValue func, Object thisArg) {
        for (int i = 0; i < arr.size(); i++) {
            if (arr.has(i)) func.call(ctx, thisArg, arr.get(i), i, arr);
        }
    }

-    @Native(thisArg = true) public static ArrayValue flat(Context ctx, ArrayValue arr, int depth) throws InterruptedException {
+    @Native(thisArg = true) public static Object reduce(Context ctx, ArrayValue arr, FunctionValue func, Object... args) {
+        var i = 0;
+        var res = arr.get(0);
+
+        if (args.length > 0) res = args[0];
+        else for (; !arr.has(i) && i < arr.size(); i++) res = arr.get(i);
+
+        for (; i < arr.size(); i++) {
+            if (arr.has(i)) {
+                res = func.call(ctx, null, res, arr.get(i), i, arr);
+            }
+        }
+
+        return res;
+    }
+    @Native(thisArg = true) public static Object reduceRight(Context ctx, ArrayValue arr, FunctionValue func, Object... args) {
+        var i = arr.size();
+        var res = arr.get(0);
+
+        if (args.length > 0) res = args[0];
+        else while (!arr.has(i--) && i >= 0) res = arr.get(i);
+
+        for (; i >= 0; i--) {
+            if (arr.has(i)) {
+                res = func.call(ctx, null, res, arr.get(i), i, arr);
+            }
+        }
+
+        return res;
+    }
+
+    @Native(thisArg = true) public static ArrayValue flat(Context ctx, ArrayValue arr, int depth) {
        var res = new ArrayValue(arr.size());
        var stack = new Stack<Object>();
        var depths = new Stack<Integer>();
@@ -197,18 +220,18 @@ public class ArrayPolyfill {

        return res;
    }
-    @Native(thisArg = true) public static ArrayValue flatMap(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue flatMap(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) {
        return flat(ctx, map(ctx, arr, cmp, thisArg), 1);
    }

-    @Native(thisArg = true) public static Object find(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static Object find(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) {
        for (int i = 0; i < arr.size(); i++) {
            if (arr.has(i) && Values.toBoolean(cmp.call(ctx, thisArg, arr.get(i), i, arr))) return arr.get(i);
        }

        return null;
    }
-    @Native(thisArg = true) public static Object findLast(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static Object findLast(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) {
        for (var i = arr.size() - 1; i >= 0; i--) {
            if (arr.has(i) && Values.toBoolean(cmp.call(ctx, thisArg, arr.get(i), i, arr))) return arr.get(i);
        }
@@ -216,14 +239,14 @@ public class ArrayPolyfill {
        return null;
    }

-    @Native(thisArg = true) public static int findIndex(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static int findIndex(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) {
        for (int i = 0; i < arr.size(); i++) {
            if (arr.has(i) && Values.toBoolean(cmp.call(ctx, thisArg, arr.get(i), i, arr))) return i;
        }

        return -1;
    }
-    @Native(thisArg = true) public static int findLastIndex(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) throws InterruptedException {
+    @Native(thisArg = true) public static int findLastIndex(Context ctx, ArrayValue arr, FunctionValue cmp, Object thisArg) {
        for (var i = arr.size() - 1; i >= 0; i--) {
            if (arr.has(i) && Values.toBoolean(cmp.call(ctx, thisArg, arr.get(i), i, arr))) return i;
        }
@@ -231,16 +254,16 @@ public class ArrayPolyfill {
        return -1;
    }

-    @Native(thisArg = true) public static int indexOf(Context ctx, ArrayValue arr, Object val, int start) throws InterruptedException {
+    @Native(thisArg = true) public static int indexOf(Context ctx, ArrayValue arr, Object val, int start) {
        start = normalizeI(arr.size(), start, true);

-        for (int i = 0; i < arr.size() && i < start; i++) {
+        for (int i = start; i < arr.size(); i++) {
            if (Values.strictEquals(ctx, arr.get(i), val)) return i;
        }

        return -1;
    }
-    @Native(thisArg = true) public static int lastIndexOf(Context ctx, ArrayValue arr, Object val, int start) throws InterruptedException {
+    @Native(thisArg = true) public static int lastIndexOf(Context ctx, ArrayValue arr, Object val, int start) {
        start = normalizeI(arr.size(), start, true);

        for (int i = arr.size(); i >= start; i--) {
@@ -250,48 +273,46 @@ public class ArrayPolyfill {
        return -1;
    }

-    @Native(thisArg = true) public static boolean includes(Context ctx, ArrayValue arr, Object el, int start) throws InterruptedException {
+    @Native(thisArg = true) public static boolean includes(Context ctx, ArrayValue arr, Object el, int start) {
        return indexOf(ctx, arr, el, start) >= 0;
    }

-    @Native(thisArg = true) public static Object pop(Context ctx, ArrayValue arr) throws InterruptedException {
+    @Native(thisArg = true) public static Object pop(Context ctx, ArrayValue arr) {
        if (arr.size() == 0) return null;
        var val = arr.get(arr.size() - 1);
        arr.shrink(1);
        return val;
    }
-    @Native(thisArg = true) public static int push(Context ctx, ArrayValue arr, Object ...values) throws InterruptedException {
+    @Native(thisArg = true) public static int push(Context ctx, ArrayValue arr, Object ...values) {
        arr.copyFrom(ctx, values, 0, arr.size(), values.length);
        return arr.size();
    }

-    @Native(thisArg = true) public static Object shift(Context ctx, ArrayValue arr) throws InterruptedException {
+    @Native(thisArg = true) public static Object shift(Context ctx, ArrayValue arr) {
        if (arr.size() == 0) return null;
        var val = arr.get(0);
        arr.move(1, 0, arr.size());
        arr.shrink(1);
        return val;
    }
-    @Native(thisArg = true) public static int unshift(Context ctx, ArrayValue arr, Object ...values) throws InterruptedException {
+    @Native(thisArg = true) public static int unshift(Context ctx, ArrayValue arr, Object ...values) {
        arr.move(0, values.length, arr.size());
        arr.copyFrom(ctx, values, 0, 0, values.length);
        return arr.size();
    }

-    @Native(thisArg = true) public static ArrayValue slice(Context ctx, ArrayValue arr, int start, int end) {
+    @Native(thisArg = true) public static ArrayValue slice(Context ctx, ArrayValue arr, int start, Object _end) {
        start = normalizeI(arr.size(), start, true);
-        end = normalizeI(arr.size(), end, true);
+        int end = normalizeI(arr.size(), (int)(_end == null ? arr.size() : Values.toNumber(ctx, _end)), true);

        var res = new ArrayValue(end - start);
        arr.copyTo(ctx, res, start, 0, end - start);
        return res;
    }
-    @Native(thisArg = true) public static ArrayValue slice(Context ctx, ArrayValue arr, int start) {
-        return slice(ctx, arr, start, arr.size());
-    }

-    @Native(thisArg = true) public static ArrayValue splice(Context ctx, ArrayValue arr, int start, int deleteCount, Object ...items) throws InterruptedException {
+    @Native(thisArg = true) public static ArrayValue splice(Context ctx, ArrayValue arr, int start, Object _deleteCount, Object ...items) {
        start = normalizeI(arr.size(), start, true);
+        int deleteCount = _deleteCount == null ? arr.size() - 1 : (int)Values.toNumber(ctx, _deleteCount);
        deleteCount = normalizeI(arr.size(), deleteCount, true);
        if (start + deleteCount >= arr.size()) deleteCount = arr.size() - start;

@@ -304,21 +325,20 @@ public class ArrayPolyfill {

        return res;
    }
-    @Native(thisArg = true) public static ArrayValue splice(Context ctx, ArrayValue arr, int start) throws InterruptedException {
-        return splice(ctx, arr, start, arr.size() - start);
-    }
-    @Native(thisArg = true) public static String toString(Context ctx, ArrayValue arr) throws InterruptedException {
+    @Native(thisArg = true) public static String toString(Context ctx, ArrayValue arr) {
        return join(ctx, arr, ",");
    }

-    @Native(thisArg = true) public static String join(Context ctx, ArrayValue arr, String sep) throws InterruptedException {
+    @Native(thisArg = true) public static String join(Context ctx, ArrayValue arr, String sep) {
        var res = new StringBuilder();
-        var comma = true;
+        var comma = false;

        for (int i = 0; i < arr.size(); i++) {
            if (!arr.has(i)) continue;
+
            if (comma) res.append(sep);
-            comma = false;
+            comma = true;
+
            var el = arr.get(i);
            if (el == null || el == Values.NULL) continue;

@@ -350,8 +370,4 @@ public class ArrayPolyfill {

        return res;
    }
-
-    @NativeInit(InitType.PROTOTYPE) public static void init(Environment env, ObjectValue target) {
-        target.defineProperty(null, env.symbol("Symbol.typeName"), "Array");
-    }
 }
--- a/src/me/topchetoeu/jscript/polyfills/AsyncFunctionPolyfill.java
+++ b/src/me/topchetoeu/jscript/polyfills/AsyncFunctionPolyfill.java
@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.polyfills;
+package me.topchetoeu.jscript.lib;

 import me.topchetoeu.jscript.engine.Context;
 import me.topchetoeu.jscript.engine.frame.CodeFrame;
@@ -7,19 +7,21 @@ import me.topchetoeu.jscript.engine.values.CodeFunction;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
 import me.topchetoeu.jscript.engine.values.NativeFunction;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.interop.Native;

-public class AsyncFunctionPolyfill extends FunctionValue {
+@Native("AsyncFunction") public class AsyncFunctionLib extends FunctionValue {
    public final FunctionValue factory;

    public static class AsyncHelper {
-        public PromisePolyfill promise = new PromisePolyfill();
+        public PromiseLib promise = new PromiseLib();
        public CodeFrame frame;

        private boolean awaiting = false;

-        private void next(Context ctx, Object inducedValue, Object inducedError) throws InterruptedException {
+        private void next(Context ctx, Object inducedValue, Object inducedError) {
            Object res = null;
-            ctx.message.pushFrame(ctx, frame);
+            ctx.pushFrame(frame);
+            ctx.pushEnv(frame.function.environment);

            awaiting = false;
            while (!awaiting) {
@@ -37,18 +39,18 @@ public class AsyncFunctionPolyfill extends FunctionValue {
                }
            }

-            ctx.message.popFrame(frame);
+            ctx.popFrame(frame);

            if (awaiting) {
-                PromisePolyfill.then(ctx, frame.pop(), new NativeFunction(this::fulfill), new NativeFunction(this::reject));
+                PromiseLib.then(ctx, frame.pop(), new NativeFunction(this::fulfill), new NativeFunction(this::reject));
            }
        }

-        public Object fulfill(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
+        public Object fulfill(Context ctx, Object thisArg, Object ...args) {
            next(ctx, args.length > 0 ? args[0] : null, Runners.NO_RETURN);
            return null;
        }
-        public Object reject(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
+        public Object reject(Context ctx, Object thisArg, Object ...args) {
            next(ctx, Runners.NO_RETURN, args.length > 0 ? args[0] : null);
            return null;
        }
@@ -60,7 +62,7 @@ public class AsyncFunctionPolyfill extends FunctionValue {
    }

    @Override
-    public Object call(Context ctx, Object thisArg, Object ...args) throws InterruptedException {
+    public Object call(Context ctx, Object thisArg, Object ...args) {
        var handler = new AsyncHelper();
        var func = factory.call(ctx, thisArg, new NativeFunction("await", handler::await));
        if (!(func instanceof CodeFunction)) throw EngineException.ofType("Return value of argument must be a js function.");
@@ -69,7 +71,7 @@ public class AsyncFunctionPolyfill extends FunctionValue {
        return handler.promise;
    }

-    public AsyncFunctionPolyfill(FunctionValue factory) {
+    public AsyncFunctionLib(FunctionValue factory) {
        super(factory.name, factory.length);
        this.factory = factory;
    }
--- a/src/me/topchetoeu/jscript/lib/AsyncGeneratorFunctionLib.java
+++ b/src/me/topchetoeu/jscript/lib/AsyncGeneratorFunctionLib.java
@@ -0,0 +1,30 @@
+package me.topchetoeu.jscript.lib;
+
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.engine.values.CodeFunction;
+import me.topchetoeu.jscript.engine.values.FunctionValue;
+import me.topchetoeu.jscript.engine.values.NativeFunction;
+import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.interop.Native;
+
+@Native("AsyncGeneratorFunction") public class AsyncGeneratorFunctionLib extends FunctionValue {
+    public final FunctionValue factory;
+
+    @Override
+    public Object call(Context ctx, Object thisArg, Object ...args) {
+        var handler = new AsyncGeneratorLib();
+        var func = factory.call(ctx, thisArg,
+            new NativeFunction("await", handler::await),
+            new NativeFunction("yield", handler::yield)
+        );
+        if (!(func instanceof CodeFunction)) throw EngineException.ofType("Return value of argument must be a js function.");
+        handler.frame = new CodeFrame(ctx, thisArg, args, (CodeFunction)func);
+        return handler;
+    }
+
+    public AsyncGeneratorFunctionLib(FunctionValue factory) {
+        super(factory.name, factory.length);
+        this.factory = factory;
+    }
+}
--- a/src/me/topchetoeu/jscript/lib/AsyncGeneratorLib.java
+++ b/src/me/topchetoeu/jscript/lib/AsyncGeneratorLib.java
@@ -0,0 +1,110 @@
+package me.topchetoeu.jscript.lib;
+
+import java.util.Map;
+
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.engine.frame.Runners;
+import me.topchetoeu.jscript.engine.values.NativeFunction;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.interop.Native;
+
+@Native("AsyncGenerator") public class AsyncGeneratorLib {
+    @Native("@@Symbol.typeName") public final String name = "AsyncGenerator";
+    private int state = 0;
+    private boolean done = false;
+    private PromiseLib currPromise;
+    public CodeFrame frame;
+
+    private void next(Context ctx, Object inducedValue, Object inducedReturn, Object inducedError) {
+        if (done) {
+            if (inducedError != Runners.NO_RETURN) throw new EngineException(inducedError);
+            currPromise.fulfill(ctx, new ObjectValue(ctx, Map.of(
+                "done", true,
+                "value", inducedReturn == Runners.NO_RETURN ? null : inducedReturn
+            )));
+            return;
+        }
+
+        Object res = null;
+        ctx.pushFrame(frame);
+        state = 0;
+
+        while (state == 0) {
+            try {
+                res = frame.next(ctx, inducedValue, inducedReturn, inducedError == Runners.NO_RETURN ? null : new EngineException(inducedError));
+                inducedValue = inducedReturn = inducedError = Runners.NO_RETURN;
+                if (res != Runners.NO_RETURN) {
+                    var obj = new ObjectValue();
+                    obj.defineProperty(ctx, "done", true);
+                    obj.defineProperty(ctx, "value", res);
+                    currPromise.fulfill(ctx, obj);
+                    break;
+                }
+            }
+            catch (EngineException e) {
+                currPromise.reject(ctx, e.value);
+                break;
+            }
+        }
+
+        ctx.popFrame(frame);
+
+        if (state == 1) {
+            PromiseLib.then(ctx, frame.pop(), new NativeFunction(this::fulfill), new NativeFunction(this::reject));
+        }
+        else if (state == 2) {
+            var obj = new ObjectValue();
+            obj.defineProperty(ctx, "done", false);
+            obj.defineProperty(ctx, "value", frame.pop());
+            currPromise.fulfill(ctx, obj);
+        }
+    }
+
+    @Override
+    public String toString() {
+        if (done) return "Generator [closed]";
+        if (state != 0) return "Generator [suspended]";
+        return "Generator [running]";
+    }
+
+    public Object fulfill(Context ctx, Object thisArg, Object ...args) {
+        next(ctx, args.length > 0 ? args[0] : null, Runners.NO_RETURN, Runners.NO_RETURN);
+        return null;
+    }
+    public Object reject(Context ctx, Object thisArg, Object ...args) {
+        next(ctx, Runners.NO_RETURN, args.length > 0 ? args[0] : null, Runners.NO_RETURN);
+        return null;
+    }
+
+    @Native
+    public PromiseLib next(Context ctx, Object ...args) {
+        this.currPromise = new PromiseLib();
+        if (args.length == 0) next(ctx, Runners.NO_RETURN, Runners.NO_RETURN, Runners.NO_RETURN);
+        else next(ctx, args[0], Runners.NO_RETURN, Runners.NO_RETURN);
+        return this.currPromise;
+    }
+    @Native("throw")
+    public PromiseLib _throw(Context ctx, Object error) {
+        this.currPromise = new PromiseLib();
+        next(ctx, Runners.NO_RETURN, Runners.NO_RETURN, error);
+        return this.currPromise;
+    }
+    @Native("return")
+    public PromiseLib _return(Context ctx, Object value) {
+        this.currPromise = new PromiseLib();
+        next(ctx, Runners.NO_RETURN, value, Runners.NO_RETURN);
+        return this.currPromise;
+    }
+
+
+    public Object await(Context ctx, Object thisArg, Object[] args) {
+        this.state = 1;
+        return args.length > 0 ? args[0] : null;
+    }
+    public Object yield(Context ctx, Object thisArg, Object[] args) {
+        this.state = 2;
+        return args.length > 0 ? args[0] : null;
+    }
+}
--- a/src/me/topchetoeu/jscript/polyfills/BooleanPolyfill.java
+++ b/src/me/topchetoeu/jscript/polyfills/BooleanPolyfill.java
@@ -1,17 +1,14 @@
-package me.topchetoeu.jscript.polyfills;
+package me.topchetoeu.jscript.lib;

 import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.Environment;
 import me.topchetoeu.jscript.engine.values.ObjectValue;
 import me.topchetoeu.jscript.engine.values.Values;
-import me.topchetoeu.jscript.interop.InitType;
 import me.topchetoeu.jscript.interop.Native;
 import me.topchetoeu.jscript.interop.NativeConstructor;
-import me.topchetoeu.jscript.interop.NativeInit;

-public class BooleanPolyfill {
-    public static final BooleanPolyfill TRUE = new BooleanPolyfill(true);
-    public static final BooleanPolyfill FALSE = new BooleanPolyfill(false);
+@Native("Boolean") public class BooleanLib {
+    public static final BooleanLib TRUE = new BooleanLib(true);
+    public static final BooleanLib FALSE = new BooleanLib(false);

    public final boolean value;

@@ -27,10 +24,7 @@ public class BooleanPolyfill {
        return Values.toBoolean(thisArg);
    }

-    public BooleanPolyfill(boolean val) {
+    public BooleanLib(boolean val) {
        this.value = val;
    }
-    @NativeInit(InitType.PROTOTYPE) public static void init(Environment env, ObjectValue target) {
-        target.defineProperty(null, env.symbol("Symbol.typeName"), "Boolean");
-    }
 }
--- a/src/me/topchetoeu/jscript/polyfills/Date.java
+++ b/src/me/topchetoeu/jscript/polyfills/Date.java
@@ -1,302 +1,275 @@
-package me.topchetoeu.jscript.polyfills;
-
-import java.util.Calendar;
-import java.util.TimeZone;
-
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.values.Values;
-import me.topchetoeu.jscript.interop.Native;
-
-public class Date {
-    private Calendar normal;
-    private Calendar utc;
-
-    public Date(long timestamp) {
-        normal = Calendar.getInstance();
-        utc = Calendar.getInstance();
-        normal.setTimeInMillis(timestamp);
-        utc.setTimeZone(TimeZone.getTimeZone("UTC"));
-        utc.setTimeInMillis(timestamp);
-    }
-
-    @Native
-    public Date() {
-        this(new java.util.Date().getTime());
-    }
-
-    private void updateUTC() {
-        if (utc == null || normal == null) return;
-        utc.setTimeInMillis(normal.getTimeInMillis());
-    }
-    private void updateNormal() {
-        if (utc == null || normal == null) return;
-        normal.setTimeInMillis(utc.getTimeInMillis());
-    }
-    private void invalidate() {
-        normal = utc = null;
-    }
-
-    @Native
-    public static double now() {
-        return new Date().getTime();
-    }
-
-    @Native
-    public double getYear() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.YEAR) - 1900;
-    }
-    @Native
-    public double setYear(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (real >= 0 && real <= 99) real = real + 1900;
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.YEAR, (int)real);
-        updateUTC();
-        return getTime();
-    }
-
-    @Native
-    public double getFullYear() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.YEAR);
-    }
-    @Native
-    public double getMonth() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.MONTH);
-    }
-    @Native
-    public double getDate() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.DAY_OF_MONTH);
-    }
-    @Native
-    public double getDay() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.DAY_OF_WEEK);
-    }
-    @Native
-    public double getHours() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.HOUR_OF_DAY);
-    }
-    @Native
-    public double getMinutes() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.MINUTE);
-    }
-    @Native
-    public double getSeconds() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.SECOND);
-    }
-    @Native
-    public double getMilliseconds() {
-        if (normal == null) return Double.NaN;
-        return normal.get(Calendar.MILLISECOND);
-    }
-
-    @Native
-    public double getUTCFullYear() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.YEAR);
-    }
-    @Native
-    public double getUTCMonth() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.MONTH);
-    }
-    @Native
-    public double getUTCDate() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.DAY_OF_MONTH);
-    }
-    @Native
-    public double getUTCDay() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.DAY_OF_WEEK);
-    }
-    @Native
-    public double getUTCHours() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.HOUR_OF_DAY);
-    }
-    @Native
-    public double getUTCMinutes() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.MINUTE);
-    }
-    @Native
-    public double getUTCSeconds() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.SECOND);
-    }
-    @Native
-    public double getUTCMilliseconds() {
-        if (utc == null) return Double.NaN;
-        return utc.get(Calendar.MILLISECOND);
-    }
-
-    @Native
-    public double setFullYear(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.YEAR, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setMonth(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.MONTH, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setDate(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.DAY_OF_MONTH, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setDay(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.DAY_OF_WEEK, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setHours(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.HOUR_OF_DAY, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setMinutes(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.MINUTE, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setSeconds(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.SECOND, (int)real);
-        updateUTC();
-        return getTime();
-    }
-    @Native
-    public double setMilliseconds(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else normal.set(Calendar.MILLISECOND, (int)real);
-        updateUTC();
-        return getTime();
-    }
-
-    @Native
-    public double setUTCFullYear(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.YEAR, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCMonth(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.MONTH, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCDate(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.DAY_OF_MONTH, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCDay(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.DAY_OF_WEEK, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCHours(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.HOUR_OF_DAY, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCMinutes(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.MINUTE, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCSeconds(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.SECOND, (int)real);
-        updateNormal();
-        return getTime();
-    }
-    @Native
-    public double setUTCMilliseconds(Context ctx, Object val) throws InterruptedException {
-        var real = Values.toNumber(ctx, val);
-        if (Double.isNaN(real)) invalidate();
-        else utc.set(Calendar.MILLISECOND, (int)real);
-        updateNormal();
-        return getTime();
-    }
-
-    @Native
-    public double getTime() {
-        if (utc == null) return Double.NaN;
-        return utc.getTimeInMillis();
-    }
-    @Native
-    public double getTimezoneOffset() {
-        if (normal == null) return Double.NaN;
-        return normal.getTimeZone().getRawOffset() / 60000;
-    }
-
-    @Native
-    public double valueOf() {
-        if (normal == null) return Double.NaN;
-        else return normal.getTimeInMillis();
-    }
-
-    // I'm not dealing with locales rn
-
-    // @Native
-    // public String toTimeString() {
-    //     if (normal == null || utc == null) return "Invalid date";
-
-    //     var res = "";
-        
-    // }
-    // @Native @Override
-    // public String toString() {
-    //     if (normal == null || utc == null) return "Invalid date";
-    //     else return DateFormat..format(normal.getTime());
-    // }
-}
+package me.topchetoeu.jscript.lib;
+
+import java.util.Calendar;
+import java.util.TimeZone;
+
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.interop.Native;
+
+@Native("Date") public class DateLib {
+    private Calendar normal;
+    private Calendar utc;
+
+    private void updateUTC() {
+        if (utc == null || normal == null) return;
+        utc.setTimeInMillis(normal.getTimeInMillis());
+    }
+    private void updateNormal() {
+        if (utc == null || normal == null) return;
+        normal.setTimeInMillis(utc.getTimeInMillis());
+    }
+    private void invalidate() {
+        normal = utc = null;
+    }
+
+    @Native
+    public static double now() {
+        return new DateLib().getTime();
+    }
+
+    @Native
+    public double getYear() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.YEAR) - 1900;
+    }
+    @Native
+    public double setYear(Context ctx, double real) {
+        if (real >= 0 && real <= 99) real = real + 1900;
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.YEAR, (int)real);
+        updateUTC();
+        return getTime();
+    }
+
+    @Native
+    public double getFullYear() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.YEAR);
+    }
+    @Native
+    public double getMonth() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.MONTH);
+    }
+    @Native
+    public double getDate() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.DAY_OF_MONTH);
+    }
+    @Native
+    public double getDay() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.DAY_OF_WEEK);
+    }
+    @Native
+    public double getHours() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.HOUR_OF_DAY);
+    }
+    @Native
+    public double getMinutes() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.MINUTE);
+    }
+    @Native
+    public double getSeconds() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.SECOND);
+    }
+    @Native
+    public double getMilliseconds() {
+        if (normal == null) return Double.NaN;
+        return normal.get(Calendar.MILLISECOND);
+    }
+
+    @Native
+    public double getUTCFullYear() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.YEAR);
+    }
+    @Native
+    public double getUTCMonth() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.MONTH);
+    }
+    @Native
+    public double getUTCDate() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.DAY_OF_MONTH);
+    }
+    @Native
+    public double getUTCDay() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.DAY_OF_WEEK);
+    }
+    @Native
+    public double getUTCHours() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.HOUR_OF_DAY);
+    }
+    @Native
+    public double getUTCMinutes() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.MINUTE);
+    }
+    @Native
+    public double getUTCSeconds() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.SECOND);
+    }
+    @Native
+    public double getUTCMilliseconds() {
+        if (utc == null) return Double.NaN;
+        return utc.get(Calendar.MILLISECOND);
+    }
+
+    @Native
+    public double setFullYear(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.YEAR, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setMonth(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.MONTH, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setDate(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.DAY_OF_MONTH, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setDay(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.DAY_OF_WEEK, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setHours(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.HOUR_OF_DAY, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setMinutes(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.MINUTE, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setSeconds(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.SECOND, (int)real);
+        updateUTC();
+        return getTime();
+    }
+    @Native
+    public double setMilliseconds(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else normal.set(Calendar.MILLISECOND, (int)real);
+        updateUTC();
+        return getTime();
+    }
+
+    @Native
+    public double setUTCFullYear(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.YEAR, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCMonth(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.MONTH, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCDate(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.DAY_OF_MONTH, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCDay(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.DAY_OF_WEEK, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCHours(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.HOUR_OF_DAY, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCMinutes(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.MINUTE, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCSeconds(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.SECOND, (int)real);
+        updateNormal();
+        return getTime();
+    }
+    @Native
+    public double setUTCMilliseconds(Context ctx, double real) {
+        if (Double.isNaN(real)) invalidate();
+        else utc.set(Calendar.MILLISECOND, (int)real);
+        updateNormal();
+        return getTime();
+    }
+
+    @Native
+    public double getTime() {
+        if (utc == null) return Double.NaN;
+        return utc.getTimeInMillis();
+    }
+    @Native
+    public double getTimezoneOffset() {
+        if (normal == null) return Double.NaN;
+        return normal.getTimeZone().getRawOffset() / 60000;
+    }
+
+    @Native
+    public double valueOf() {
+        if (normal == null) return Double.NaN;
+        else return normal.getTimeInMillis();
+    }
+
+    @Native
+    public String toString() {
+        return normal.getTime().toString();
+    }
+
+    @Native
+    public DateLib(long timestamp) {
+        normal = Calendar.getInstance();
+        utc = Calendar.getInstance();
+        normal.setTimeInMillis(timestamp);
+        utc.setTimeZone(TimeZone.getTimeZone("UTC"));
+        utc.setTimeInMillis(timestamp);
+    }
+
+    @Native
+    public DateLib() {
+        this(new java.util.Date().getTime());
+    }
+}
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
TopchetoEU	4f22e76d2b	fix: make code java 11 compatible	2023-11-25 20:22:16 +02:00
TopchetoEU	8924e7aadc	build: fix build script to exit with code when error occurs	2023-11-25 20:16:06 +02:00
TopchetoEU	1d0e31a423	Merge pull request #9 from TopchetoEU/TopchetoEU/perms-and-fs Permissions and filesystems	2023-11-25 20:10:59 +02:00
TopchetoEU	ab56908171	fix: faulty insufficient permissions error	2023-11-25 20:09:59 +02:00
TopchetoEU	eb14bb080c	fix: debugger breakpoints not registered	2023-11-25 20:09:47 +02:00
TopchetoEU	f52f47cdb4	feat: properly implement filesystems	2023-11-25 19:36:18 +02:00
TopchetoEU	567eaa8514	fix: incorrect declarations	2023-11-25 19:13:20 +02:00
TopchetoEU	2cfdd8e335	feat: add utf8 encoding and decoding	2023-11-25 19:12:56 +02:00
TopchetoEU	4b1ec671e2	fix: micro tasks not handled properly	2023-11-25 18:58:35 +02:00
TopchetoEU	b127aadcf6	fix: promise was sending macro tasks instead of micro	2023-11-25 18:58:24 +02:00
TopchetoEU	b6eaff65ca	style: remove unnececeary import	2023-11-25 18:48:46 +02:00
TopchetoEU	443dc0ffa1	feat: add await function to promise	2023-11-25 18:47:51 +02:00
TopchetoEU	e107dd3507	fix: promise doesn't use microtasks in some cases	2023-11-25 18:47:36 +02:00
TopchetoEU	6af3c70fce	feat: add filesystem libs	2023-11-25 18:47:01 +02:00
TopchetoEU	8b743f49d1	feat: add toString, equals and hashCode overrides to wrappers and objects	2023-11-25 18:46:13 +02:00
TopchetoEU	e1ce384815	feat: add parse function to Filename	2023-11-25 18:44:27 +02:00
TopchetoEU	86d205e521	fix: parsing files won't modify last instruction to RET, instead will just append it	2023-11-25 18:44:11 +02:00
TopchetoEU	f0ad936e5b	refactor: use new iterable names	2023-11-25 18:43:43 +02:00
TopchetoEU	4a1473c5be	fix: sorting with no comparator now works	2023-11-25 18:42:54 +02:00
TopchetoEU	4111dbf5c4	fix: functions now print their name when stringified	2023-11-25 18:41:47 +02:00
TopchetoEU	1666682dc2	refactor: get rid of data parent hierarchy	2023-11-25 18:41:18 +02:00
TopchetoEU	f2b33d0233	feat: add support for async iterators fix: comparasions had small behavioural issue	2023-11-25 18:40:49 +02:00
TopchetoEU	f5a0b6eaf7	fix: some improvements of compiled bytecode	2023-11-25 18:38:43 +02:00
TopchetoEU	829bea755d	fix: CodeFrame didnt't handle out of bounds jumps well	2023-11-25 18:38:16 +02:00
TopchetoEU	4b0dcffd13	feat: add fs declarations in lib.d.ts	2023-11-25 18:37:40 +02:00
TopchetoEU	987f8b8f00	fix: handle native errors properly-ish	2023-11-25 14:18:46 +02:00
TopchetoEU	55e3d46bc2	feat: implement memory and root fs	2023-11-25 14:18:04 +02:00
TopchetoEU	3e25068219	feat: implement bulk of fs	2023-11-25 14:17:37 +02:00
TopchetoEU	7ecb8bfabb	feat: implement permissions	2023-11-25 14:16:02 +02:00
TopchetoEU	488deea164	fix: improve performance of typescript by caching separate declarations	2023-11-14 09:24:39 +02:00
TopchetoEU	ed08041335	fix: internal error when trying to use key of "undefined"	2023-11-14 09:24:00 +02:00
TopchetoEU	0a4149ba81	fix: remove double space in "Uncaught ..."	2023-11-14 09:23:15 +02:00
TopchetoEU	30f5d619c3	fix: errors now have the right prototype and name	2023-11-14 09:22:56 +02:00
TopchetoEU	e7dbe91374	refactor: clean up protocol.json	2023-11-13 20:06:07 +02:00
TopchetoEU	455f5a613e	feat: implement simple permission matching	2023-11-13 19:09:33 +02:00
TopchetoEU	1eeac3ae97	fix: replace templates in Metadata class with placeholder data	2023-11-13 19:08:56 +02:00
TopchetoEU	1acd78e119	refactor: clean up Main class	2023-11-13 18:56:59 +02:00
TopchetoEU	df9932874d	feat: remove unnececeary @NativeInit directives	2023-11-06 14:03:15 +02:00
TopchetoEU	b47d1a7576	refactor: remove StackData and Data usage	2023-11-06 13:53:36 +02:00
TopchetoEU	fdfa8d7713	refactor: some minor fixes, rewrite README example	2023-11-06 10:55:38 +02:00
TopchetoEU	f5d1287948	fix: some annoying bugs, as well as splice	2023-11-06 00:55:30 +02:00
TopchetoEU	15f4278cb1	fix: build with java 17	2023-11-05 21:00:39 +02:00
TopchetoEU	df8465cb49	Merge pull request #8 from TopchetoEU/TopchetoEU/tests Integrate typescript	2023-11-05 20:32:42 +02:00
TopchetoEU	e3104c223c	fix: remove some unnececeary logs	2023-11-05 20:29:21 +02:00
TopchetoEU	1d0bae3de8	feat: include typescript code in source code	2023-11-05 20:27:23 +02:00
TopchetoEU	b66acd3089	fix: several more fixes	2023-11-05 19:44:44 +02:00
TopchetoEU	e326847287	feat: send value stack to debug client	2023-11-05 19:44:35 +02:00
TopchetoEU	26591d6631	fix: lazy operators incorrectly pop values from stack	2023-11-05 19:44:08 +02:00
TopchetoEU	af31b1ab79	fix: several small fixes	2023-11-05 19:43:53 +02:00
TopchetoEU	f885d4349f	refactor: fix some bad code >:(	2023-11-05 19:43:28 +02:00
TopchetoEU	d57044acb7	fix: several bug fixes to help with typescript support	2023-11-05 12:44:29 +02:00
TopchetoEU	7df4e3b03f	fix: oops	2023-11-04 11:43:57 +02:00
TopchetoEU	ed1009ab69	refactor: some code restructuring in the debugging	2023-11-04 11:42:06 +02:00
TopchetoEU	f856cdf37e	fix: messages larger than 64KB are now fragmented properly	2023-11-04 11:41:31 +02:00
TopchetoEU	4f82574b8c	fix: various small behavioural issues fix: pesky try-catch logic	2023-11-04 11:40:50 +02:00
TopchetoEU	0ae24148d8	feat: write some tests	2023-11-04 11:38:48 +02:00
TopchetoEU	ac128d17f4	feat: implement Array.reduce fix: native functions are now named	2023-11-04 11:38:29 +02:00
TopchetoEU	6508f15bb0	refactor: remove typescript source code from repo (for now)	2023-11-04 11:37:13 +02:00
TopchetoEU	69f93b4f87	refactor: make filenames more consistent	2023-11-04 11:36:36 +02:00
TopchetoEU	b675411925	fix: a lot of minor bugs	2023-10-29 23:47:48 +02:00
TopchetoEU	d1e93c2088	Merge branch 'master' of https://github.com/TopchetoEU/java-jscript	2023-10-29 12:33:18 +02:00
TopchetoEU	942db54546	feat: improve vscode debugging compatibility	2023-10-29 12:30:43 +02:00
TopchetoEU	d20df66982	feat: improve vscode debugging compatibility	2023-10-29 12:25:33 +02:00
TopchetoEU	16a9e5d761	Merge pull request #7 from TopchetoEU/TopcehtoEU/debugging Debugging support	2023-10-28 17:11:55 +03:00
TopchetoEU	dc9d84a370	chore: nothing of use	2023-10-28 17:10:27 +03:00
TopchetoEU	edb71daef4	feat: fully implement local and capture scope object wrappers feat: implement object sending and receiving	2023-10-28 16:58:33 +03:00
TopchetoEU	4b84309df6	feat: complete steptrough and breakpoints in debugger	2023-10-27 15:12:14 +03:00
TopchetoEU	d2d9fa9738	fix: exit now works	2023-10-07 14:08:47 +03:00
TopchetoEU	a4e5f7f471	refactor: clean up useless catch blocks	2023-10-07 13:55:44 +03:00
TopchetoEU	cc044374ba	refactor: replace InterruptedException with unchecked alternative	2023-10-07 13:42:55 +03:00
TopchetoEU	517e3e6657	refactor: clean up context and stack data	2023-10-07 13:07:07 +03:00
TopchetoEU	926b9c17d8	feat: readd JSON to lib	2023-10-06 18:42:35 +03:00
TopchetoEU	fc705e7383	feat: readd date internals	2023-10-06 12:03:33 +03:00
TopchetoEU	a17ec737b7	refactor: rename polyfills to libs	2023-10-06 11:57:29 +03:00
TopchetoEU	952a4d631d	fix: keep order of object fields	2023-10-04 22:06:49 +03:00