action attempt 1

Major codebase cleanup

.gitattributes

@@ -0,0 +1 @@
+* -text

.github/workflows/tagged-release.yml

@@ -11,15 +11,22 @@ jobs:
     runs-on: "ubuntu-latest"
 
     steps:
+      - name: Setup Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'adopt'
+          java-version: '11'
+      - name: Setup Gradle
+        uses: gradle/gradle-build-action@v2
       - name: Clone repository
         uses: GuillaumeFalourd/clone-github-repo-action@main
         with:
-          branch: 'master' # fuck this political bullshitshit, took me an hour to fix this
+          branch: 'master'
           owner: 'TopchetoEU'
           repository: 'java-jscript'
-      - name: "Build"
+      - name: Build
         run: |
-          cd java-jscript; node ./build.js release ${{ github.ref }}
+          cd java-jscript; gradle build
 
       - uses: "marvinpinto/action-automatic-releases@latest"
         with:
@@ -27,4 +34,4 @@ jobs:
           prerelease: false
           files: |
             java-jscript/LICENSE
-            java-jscript/dst/*.jar
+            java-jscript/build/libs/*.jar

.gitignore

@@ -1,11 +1,22 @@
-.vscode
-.gradle
-.ignore
-/out
-/build
-/bin
-/dst
-/*.js
+*
+
+!/src
+!/src/**/*
+
+!/doc
+!/doc/**/*
+
+!/tests
+!/tests/**/*
+
+!/.github
+!/.github/**/*
+
+!/.gitignore
+!/.gitattributes
 !/build.js
-/dead-code
-/Metadata.java
+!/LICENSE
+!/README.md
+!/settings.gradle
+!/build.gradle
+!/gradle.properties

README.md

@@ -2,33 +2,28 @@
 
 **NOTE: This had nothing to do with Microsoft's dialect of EcmaScript**
 
-**WARNING: Currently, this code is mostly undocumented. Proceed with caution and a psychiatrist.**
+**WARNING: Currently, this code is 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`:
+The following is going to execute a simple javascript statement:
 
 ```java
-var engine = new PolyfillEngine(new File("."));
-var in = new BufferedReader(new InputStreamReader(System.in));
-engine.start();
+var engine = new Engine();
+// Initialize a standard environment, with implementations of most basic standard libraries (Object, Array, Symbol, etc.)
+var env = Internals.apply(new Environment());
 
-while (true) {
-    try {
-        var raw = in.readLine();
+// Queue code to load internal libraries and start engine
+var awaitable = engine.pushMsg(false, env, new Filename("tmp", "eval"), "10 + Math.sqrt(5 / 3)", null);
+// Run the engine on the same thread, until the event loop runs empty
+engine.run(true);
 
-        var res = engine.pushMsg(false, engine.global(), Map.of(), "<stdio>", raw, null).await();
-        Values.printValue(engine.context(), res);
-        System.out.println();
-    }
-    catch (EngineException e) {
-        try {
-            System.out.println("Uncaught " + e.toString(engine.context()));
-        }
-        catch (InterruptedException _e) {  return; }
-    }
-    catch (IOException | InterruptedException e) { return; }
-}
+// Get our result
+System.out.println(awaitable.await());
 ```
+
+## NOTE:
+
+To setup the typescript bundle in your sources, run `node build.js init-ts`. This will download the latest version of typescript, minify it, and add it to your src folder. If you are going to work with the `node build.js debug|release` command, this is not a necessary step.

build.gradle

@@ -0,0 +1,29 @@
+plugins {
+    id 'application'
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
+}
+
+sourceSets {
+    main.java.srcDirs = [ 'src/java' ]
+    main.resources.srcDirs = [ 'src/assets' ]
+}
+
+processResources {
+    filesMatching('metadata.json') {
+        expand (
+            'version': project.project_version,
+            'name': project.project_name
+        )
+    }
+}
+
+application {
+    mainClass = project.main_class
+}
+
+archivesBaseName = project.project_name
+version = project.project_version

build.js

@@ -1,81 +0,0 @@
-const { spawn } = require('child_process');
-const fs = require('fs/promises');
-const pt = require('path');
-const { argv } = require('process');
-
-const conf = {
-    name: "java-jscript",
-    author: "TopchetoEU",
-    javahome: "",
-    version: argv[3]
-};
-
-console.log(conf)
-
-if (conf.version.startsWith('refs/tags/')) conf.version = conf.version.substring(10);
-if (conf.version.startsWith('v')) conf.version = conf.version.substring(1);
-
-async function* find(src, dst, wildcard) {
-    const stat = await fs.stat(src);
-
-    if (stat.isDirectory()) {
-        for (const el of await fs.readdir(src)) {
-            for await (const res of find(pt.join(src, el), dst ? pt.join(dst, el) : undefined, wildcard)) yield res;
-        }
-    }
-    else if (stat.isFile() && wildcard(src)) yield dst ? { src, dst } : src;
-}
-async function copy(src, dst, wildcard) {
-    const promises = [];
-
-    for await (const el of find(src, dst, wildcard)) {
-        promises.push((async () => {
-            await fs.mkdir(pt.dirname(el.dst), { recursive: true });
-            await fs.copyFile(el.src, el.dst);
-        })());
-    }
-
-    await Promise.all(promises);
-}
-
-function run(cmd, ...args) {
-    return new Promise((res, rej) => {
-        const proc = spawn(cmd, args, { stdio: 'inherit' });
-        proc.once('exit', code => {
-            if (code === 0) res(code);
-            else rej(new Error(`Process ${cmd} exited with code ${code}.`));
-        });
-    })
-}
-
-async function compileJava() {
-    try {
-        await fs.writeFile('Metadata.java', (await fs.readFile('src/me/topchetoeu/jscript/Metadata.java')).toString()
-            .replace('${VERSION}', conf.version)
-            .replace('${NAME}', conf.name)
-            .replace('${AUTHOR}', conf.author)
-        );
-        const args = ['--release', '11', ];
-        if (argv[2] === 'debug') args.push('-g');
-        args.push('-d', 'dst/classes', 'Metadata.java');
-    
-        for await (const path of find('src', undefined, v => v.endsWith('.java') && !v.endsWith('Metadata.java'))) args.push(path);
-        await run(conf.javahome + 'javac', ...args);
-    }
-    finally {
-        await fs.rm('Metadata.java');
-    }
-}
-
-(async () => {
-    try {
-        try { await fs.rm('dst', { recursive: true }); } catch {}
-        await copy('src', 'dst/classes', v => !v.endsWith('.java'));
-        await compileJava();
-        await run('jar', '-c', '-f', 'dst/jscript.jar', '-e', 'me.topchetoeu.jscript.Main', '-C', 'dst/classes', '.');
-    }
-    catch (e) {
-        if (argv[2] === 'debug') throw e;
-        else console.log(e.toString());
-    }
-})();

gradle.properties

@@ -0,0 +1,3 @@
+project_name = jscript
+project_version = 0.8.4-beta
+main_class = me.topchetoeu.jscript.utils.JScriptRepl

src/assets/metadata.json

@@ -0,0 +1,5 @@
+{
+    "version": "${version}",
+    "name": "${name}",
+    "author": "TopchetoEU"
+}

src/java/me/topchetoeu/jscript/common/Buffer.java

@@ -0,0 +1,53 @@
+package me.topchetoeu.jscript.common;
+
+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 void append(byte b) {
+        write(length, new byte[] { b });
+    }
+
+    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);
+    }
+    public Buffer(int capacity) {
+        this.data = new byte[capacity];
+        this.length = 0;
+    }
+    public Buffer() {
+        this.data = new byte[128];
+        this.length = 0;
+    }
+}

src/java/me/topchetoeu/jscript/common/Filename.java

@@ -1,6 +1,7 @@
-package me.topchetoeu.jscript;
+package me.topchetoeu.jscript.common;
 
 import java.io.File;
+import java.nio.file.Path;
 
 public class Filename {
     public final String protocol;
@@ -40,13 +41,25 @@ public class Filename {
         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());
+    }
+    public static Path normalize(String path) {
+        return Path.of(Path.of("/" + path.trim().replace("\\", "/")).normalize().toString().substring(1));
+    }
+    public static Filename fromFile(File file) {
+        return new Filename("file", file.getAbsolutePath());
+    }
 }

src/java/me/topchetoeu/jscript/common/Location.java

@@ -1,7 +1,7 @@
-package me.topchetoeu.jscript;
+package me.topchetoeu.jscript.common;
 
 public class Location implements Comparable<Location> {
-    public static final Location INTERNAL = new Location(0, 0, new Filename("jscript", "internal"));
+    public static final Location INTERNAL = new Location(0, 0, new Filename("jscript", "native"));
     private int line;
     private int start;
     private Filename filename;
@@ -71,4 +71,23 @@ public class Location implements Comparable<Location> {
         this.start = start;
         this.filename = filename;
     }
+
+    public static Location parse(String raw) {
+        int i0 = -1, i1 = -1;
+        for (var i = raw.length() - 1; i >= 0; i--) {
+            if (raw.charAt(i) == ':') {
+                if (i1 == -1) i1 = i;
+                else if (i0 == -1) {
+                    i0 = i;
+                    break;
+                }
+            }
+        }
+
+        return new Location(
+            Integer.parseInt(raw.substring(i0 + 1, i1)),
+            Integer.parseInt(raw.substring(i1 + 1)),
+            Filename.parse(raw.substring(0, i0))
+        );
+    }
 }

src/java/me/topchetoeu/jscript/common/Metadata.java

@@ -0,0 +1,29 @@
+package me.topchetoeu.jscript.common;
+
+import me.topchetoeu.jscript.common.json.JSON;
+
+public class Metadata {
+    private static final String VERSION;
+    private static final String AUTHOR;
+    private static final String NAME;
+
+    static {
+        var data = JSON.parse(null, Reading.resourceToString("metadata.json")).map();
+        VERSION = data.string("version");
+        AUTHOR = data.string("author");
+        NAME = data.string("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;
+    }
+}

src/java/me/topchetoeu/jscript/common/Reading.java

@@ -0,0 +1,33 @@
+package me.topchetoeu.jscript.common;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.UncheckedIOException;
+
+public class Reading {
+    private static final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+
+    public static synchronized String readline() throws IOException {
+        return reader.readLine();
+    }
+
+    /**
+     * Reads the given stream to a string
+     * @param in 
+     * @return
+     */
+    public static String streamToString(InputStream in) {
+        try {
+            return new String(in.readAllBytes());
+        }
+        catch (IOException e) { throw new UncheckedIOException(e); }
+    }
+    public static InputStream resourceToStream(String name) {
+        return Reading.class.getResourceAsStream("/" + name);
+    }
+    public static String resourceToString(String name) {
+        return streamToString(resourceToStream(name));
+    }
+}

src/java/me/topchetoeu/jscript/common/ResultRunnable.java

@@ -0,0 +1,5 @@
+package me.topchetoeu.jscript.common;
+
+public interface ResultRunnable<T> {
+    T run();
+}

src/java/me/topchetoeu/jscript/common/VLQ.java

@@ -0,0 +1,95 @@
+package me.topchetoeu.jscript.common;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class VLQ {
+    private static final String ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    private static long[] toArray(List<Long> list) {
+        var arr = new long[list.size()];
+        for (var i = 0; i < list.size(); i++) arr[i] = list.get(i);
+        return arr;
+    }
+
+    public static String encode(long... arr) {
+        var raw = new StringBuilder();
+
+        for (var data : arr) {
+            var b = data < 0 ? 1 : 0;
+            data = Math.abs(data);
+            b |= (int)(data & 0b1111) << 1;
+            data >>= 4;
+            b |=  data > 0 ? 0x20 : 0;;
+            raw.append(ALPHABET.charAt(b));
+
+            while (data > 0) {
+                b = (int)(data & 0b11111);
+                data >>= 5;
+                b |= data > 0 ? 0x20 : 0;
+                raw.append(ALPHABET.charAt(b));
+            }
+        }
+
+        return raw.toString();
+    }
+    public static long[] decode(String val) {
+        if (val.length() == 0) return new long[0];
+
+        var list = new ArrayList<Long>();
+
+        for (var i = 0; i < val.length();) {
+            var sign = 1;
+            var curr = ALPHABET.indexOf(val.charAt(i++));
+            var cont = (curr & 0x20) == 0x20;
+            if ((curr & 1) == 1) sign = -1;
+            long res = (curr & 0b11110) >> 1;
+            var n = 4;
+
+            for (; i < val.length() && cont;) {
+                curr = ALPHABET.indexOf(val.charAt(i++));
+                cont = (curr & 0x20) == 0x20;
+                res |= (curr & 0b11111) << n;
+                n += 5;
+                if (!cont) break;
+            }
+
+            list.add(res * sign);
+        }
+
+        return toArray(list);
+    }
+
+    public static String encodeMapping(long[][][] arr) {
+        var res = new StringBuilder();
+        var semicolon = false;
+        
+        for (var line : arr) {
+            var comma = false;
+
+            if (semicolon) res.append(";");
+            semicolon = true;
+
+            for (var el : line) {
+                if (comma) res.append(",");
+                comma = true;
+                res.append(encode(el));
+            }
+        }
+
+        return res.toString();
+    }
+    public static long[][][] decodeMapping(String val) {
+        var lines = new ArrayList<long[][]>();
+
+        for (var line : val.split(";", -1)) {
+            var elements = new ArrayList<long[]>();
+            for (var el : line.split(",", -1)) {
+                elements.add(decode(el));
+            }
+            lines.add(elements.toArray(long[][]::new));
+        }
+
+        return lines.toArray(long[][][]::new);
+    }
+}

src/java/me/topchetoeu/jscript/common/events/Awaitable.java

@@ -0,0 +1,27 @@
+package me.topchetoeu.jscript.common.events;
+
+public interface Awaitable<T> {
+    public static interface ResultHandler<T> {
+        public void onResult(T data);
+    }
+    public static interface ErrorHandler {
+        public void onError(RuntimeException error);
+    }
+
+    T await();
+
+    default void handle(ResultHandler<T> onResult, ErrorHandler onError) {
+        var thread = new Thread(() -> {
+            try {
+                onResult.onResult(await());
+            }
+            catch (RuntimeException e) {
+                onError.onError(e);
+            }
+        }, "Awaiter");
+        thread.start();
+    }
+    default void handle(ResultHandler<T> onResult) {
+        handle(onResult, err -> {});
+    }
+}

src/java/me/topchetoeu/jscript/common/events/DataNotifier.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.events;
+package me.topchetoeu.jscript.common.events;
 
 public class DataNotifier<T> implements Awaitable<T> {
     private Notifier notifier = new Notifier();
@@ -11,9 +11,6 @@ public class DataNotifier<T> implements Awaitable<T> {
         isErr = true;
         notifier.next();
     }
-    public void error(Throwable t) {
-        error(new RuntimeException(t));
-    }
     public void next(T val) {
         this.val = val;
         isErr = false;

src/java/me/topchetoeu/jscript/common/events/Notifier.java

@@ -1,6 +1,6 @@
-package me.topchetoeu.jscript.events;
+package me.topchetoeu.jscript.common.events;
 
-import me.topchetoeu.jscript.exceptions.InterruptException;
+import me.topchetoeu.jscript.core.exceptions.InterruptException;
 
 public class Notifier {
     private boolean ok = false;

src/java/me/topchetoeu/jscript/common/json/JSON.java

@@ -1,20 +1,20 @@
-package me.topchetoeu.jscript.json;
+package me.topchetoeu.jscript.common.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;
-import me.topchetoeu.jscript.parsing.Parsing;
-import me.topchetoeu.jscript.parsing.Token;
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.values.ArrayValue;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.core.exceptions.SyntaxException;
+import me.topchetoeu.jscript.core.parsing.Operator;
+import me.topchetoeu.jscript.core.parsing.ParseRes;
+import me.topchetoeu.jscript.core.parsing.Parsing;
+import me.topchetoeu.jscript.core.parsing.Token;
 
 public class JSON {
     public static Object toJs(JSONElement val) {
@@ -37,21 +37,6 @@ public class JSON {
         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);
@@ -67,6 +52,21 @@ public class JSON {
             prev.remove(val);
             return JSONElement.of(res);
         }
+        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 : Values.getMembers(ctx, val, false, false)) {
+                var jsonEl = fromJs(ctx, Values.getMember(ctx, val, 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 == null) return null;
         return null;
     }
@@ -83,8 +83,11 @@ public class JSON {
         else return res.transform();
     }
     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(Filename filename, List<Token> tokens, int i) {
@@ -174,6 +177,7 @@ public class JSON {
         return ParseRes.res(values, n);
     }
     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);
@@ -184,12 +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("\n", "\\n")
-            .replace("\r", "\\r")
-            .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++) {

src/java/me/topchetoeu/jscript/common/json/JSONElement.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.json;
+package me.topchetoeu.jscript.common.json;
 
 public class JSONElement {
     public static enum Type {

src/java/me/topchetoeu/jscript/common/json/JSONList.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.json;
+package me.topchetoeu.jscript.common.json;
 
 import java.util.ArrayList;
 import java.util.Collection;

src/java/me/topchetoeu/jscript/common/json/JSONMap.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.json;
+package me.topchetoeu.jscript.common.json;
 
 import java.util.Collection;
 import java.util.HashMap;

src/java/me/topchetoeu/jscript/core/compilation/AssignableStatement.java

@@ -1,7 +1,7 @@
-package me.topchetoeu.jscript.compilation;
+package me.topchetoeu.jscript.core.compilation;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.engine.Operation;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.engine.Operation;
 
 public abstract class AssignableStatement extends Statement {
     public abstract Statement toAssign(Statement val, Operation operation);

src/java/me/topchetoeu/jscript/core/compilation/CalculateResult.java

@@ -0,0 +1,21 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import me.topchetoeu.jscript.core.engine.values.Values;
+
+public final class CalculateResult {
+    public final boolean exists;
+    public final Object value;
+
+    public final boolean isTruthy() {
+        return exists && Values.toBoolean(value);
+    }
+
+    public CalculateResult(Object value) {
+        this.exists = true;
+        this.value = value;
+    }
+    public CalculateResult() {
+        this.exists = false;
+        this.value = null;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/CompileTarget.java

@@ -0,0 +1,66 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeSet;
+import java.util.Vector;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.Environment;
+import me.topchetoeu.jscript.core.engine.values.CodeFunction;
+
+public class CompileTarget {
+    public final Vector<Instruction> target = new Vector<>();
+    public final Map<Long, FunctionBody> functions;
+    public final TreeSet<Location> breakpoints;
+    private final HashMap<Location, Instruction> bpToInstr = new HashMap<>();
+
+    public Instruction add(Instruction instr) {
+        target.add(instr);
+        return instr;
+    }
+    public Instruction set(int i, Instruction instr) {
+        return target.set(i, instr);
+    }
+    public void setDebug(int i, BreakpointType type) {
+        var instr = target.get(i);
+        instr.breakpoint = type;
+
+        if (type == BreakpointType.NONE) {
+            breakpoints.remove(target.get(i).location);
+            bpToInstr.remove(instr.location, instr);
+        }
+        else {
+            breakpoints.add(target.get(i).location);
+
+            var old = bpToInstr.put(instr.location, instr);
+            if (old != null) old.breakpoint = BreakpointType.NONE;
+        }
+    }
+    public void setDebug(BreakpointType type) {
+        setDebug(target.size() - 1, type);
+    }
+    public Instruction get(int i) {
+        return target.get(i);
+    }
+    public int size() { return target.size(); }
+    public Location lastLoc(Location fallback) {
+        if (target.size() == 0) return fallback;
+        else return target.get(target.size() - 1).location;
+    }
+
+    public Instruction[] array() { return target.toArray(Instruction[]::new); }
+
+    public FunctionBody body() {
+        return functions.get(0l);
+    }
+    public CodeFunction func(Environment env) {
+        return new CodeFunction(env, "", body());
+    }
+
+    public CompileTarget(Map<Long, FunctionBody> functions, TreeSet<Location> breakpoints) {
+        this.functions = functions;
+        this.breakpoints = breakpoints;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/CompoundStatement.java

@@ -0,0 +1,64 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import java.util.List;
+import java.util.Vector;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.compilation.values.FunctionStatement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class CompoundStatement extends Statement {
+    public final Statement[] statements;
+    public final boolean separateFuncs;
+    public Location end;
+
+    @Override public boolean pure() {
+        for (var stm : statements) {
+            if (!stm.pure()) return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void declare(ScopeRecord varsScope) {
+        for (var stm : statements) stm.declare(varsScope);
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType type) {
+        List<Statement> statements = new Vector<Statement>();
+        if (separateFuncs) for (var stm : this.statements) {
+            if (stm instanceof FunctionStatement && ((FunctionStatement)stm).statement) {
+                stm.compile(target, scope, false);
+            }
+            else statements.add(stm);
+        }
+        else statements = List.of(this.statements);
+
+        var polluted = false;
+
+        for (var i = 0; i < statements.size(); i++) {
+            var stm = statements.get(i);
+
+            if (i != statements.size() - 1) stm.compile(target, scope, false, BreakpointType.STEP_OVER);
+            else stm.compile(target, scope, polluted = pollute, BreakpointType.STEP_OVER);
+        }
+
+        if (!polluted && pollute) {
+            target.add(Instruction.loadValue(loc(), null));
+        }
+    }
+
+    public CompoundStatement setEnd(Location loc) {
+        this.end = loc;
+        return this;
+    }
+
+    public CompoundStatement(Location loc, boolean separateFuncs, Statement ...statements) {
+        super(loc);
+        this.separateFuncs = separateFuncs;
+        this.statements = statements;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/FunctionBody.java

@@ -0,0 +1,29 @@
+package me.topchetoeu.jscript.core.compilation;
+
+public class FunctionBody {
+    public final Instruction[] instructions;
+    public final String[] captureNames, localNames;
+    public final int localsN, argsN;
+
+    public FunctionBody(int localsN, int argsN, Instruction[] instructions, String[] captureNames, String[] localNames) {
+        this.argsN = argsN;
+        this.localsN = localsN;
+        this.instructions = instructions;
+        this.captureNames = captureNames;
+        this.localNames = localNames;
+    }
+    public FunctionBody(int localsN, int argsN, Instruction[] instructions) {
+        this.argsN = argsN;
+        this.localsN = localsN;
+        this.instructions = instructions;
+        this.captureNames = new String[0];
+        this.localNames = new String[0];
+    }
+    public FunctionBody(Instruction... instructions) {
+        this.argsN = 0;
+        this.localsN = 2;
+        this.instructions = instructions;
+        this.captureNames = new String[0];
+        this.localNames = new String[0];
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/Instruction.java

@@ -0,0 +1,256 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.exceptions.SyntaxException;
+
+public class Instruction {
+    public static enum Type {
+        RETURN,
+        THROW,
+        THROW_SYNTAX,
+        DELETE,
+        TRY_START,
+        TRY_END,
+        NOP,
+
+        CALL,
+        CALL_NEW,
+        JMP_IF,
+        JMP_IFN,
+        JMP,
+
+        LOAD_VALUE,
+
+        LOAD_VAR,
+        LOAD_MEMBER,
+        LOAD_VAL_MEMBER,
+        LOAD_GLOB,
+
+        LOAD_FUNC,
+        LOAD_ARR,
+        LOAD_OBJ,
+        STORE_SELF_FUNC,
+        LOAD_REGEX,
+
+        DUP,
+
+        STORE_VAR,
+        STORE_MEMBER,
+        DISCARD,
+
+        MAKE_VAR,
+        DEF_PROP,
+        KEYS,
+
+        TYPEOF,
+        OPERATION;
+    }
+    public static enum BreakpointType {
+        NONE,
+        STEP_OVER,
+        STEP_IN;
+
+        public boolean shouldStepIn() {
+            return this != NONE;
+        }
+        public boolean shouldStepOver() {
+            return this == STEP_OVER;
+        }
+    }
+
+    public final Type type;
+    public final Object[] params;
+    public Location location;
+    public BreakpointType breakpoint = BreakpointType.NONE;
+
+    public Instruction setDbgData(Instruction other) {
+        this.location = other.location;
+        this.breakpoint = other.breakpoint;
+        return this;
+    }
+
+    public Instruction locate(Location loc) {
+        this.location = loc;
+        return this;
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> T get(int i) {
+        if (i >= params.length || i < 0) return null;
+        return (T)params[i];
+    }
+    @SuppressWarnings("unchecked")
+    public <T> T get(int i, T defaultVal) {
+        if (i >= params.length || i < 0) return defaultVal;
+        return (T)params[i];
+    }
+    public boolean match(Object ...args) {
+        if (args.length != params.length) return false;
+        for (int i = 0; i < args.length; i++) {
+            var a = params[i];
+            var b = args[i];
+            if (a == null || b == null) {
+                if (!(a == null && b == null)) return false;
+            }
+            if (!a.equals(b)) return false;
+        }
+        return true;
+    }
+    public boolean is(int i, Object arg) {
+        if (params.length <= i) return false;
+        return params[i].equals(arg);
+    }
+
+    private Instruction(Location location, Type type, Object ...params) {
+        this.location = location;
+        this.type = type;
+        this.params = params;
+    }
+
+    public static Instruction tryStart(Location loc, int catchStart, int finallyStart, int end) {
+        return new Instruction(loc, Type.TRY_START, catchStart, finallyStart, end);
+    }
+    public static Instruction tryEnd(Location loc) {
+        return new Instruction(loc, Type.TRY_END);
+    }
+    public static Instruction throwInstr(Location loc) {
+        return new Instruction(loc, Type.THROW);
+    }
+    public static Instruction throwSyntax(Location loc, SyntaxException err) {
+        return new Instruction(loc, Type.THROW_SYNTAX, err.getMessage());
+    }
+    public static Instruction throwSyntax(Location loc, String err) {
+        return new Instruction(loc, Type.THROW_SYNTAX, err);
+    }
+    public static Instruction delete(Location loc) {
+        return new Instruction(loc, Type.DELETE);
+    }
+    public static Instruction ret(Location loc) {
+        return new Instruction(loc, Type.RETURN);
+    }
+    public static Instruction debug(Location loc) {
+        return new Instruction(loc, Type.NOP, "debug");
+    }
+
+    public static Instruction nop(Location loc, Object ...params) {
+        for (var param : params) {
+            if (param instanceof String) continue;
+            if (param instanceof Boolean) continue;
+            if (param instanceof Double) continue;
+            if (param instanceof Integer) continue;
+            if (param == null) continue;
+
+            throw new RuntimeException("NOP params may contain only strings, booleans, doubles, integers and nulls.");
+        }
+        return new Instruction(loc, Type.NOP, params);
+    }
+
+    public static Instruction call(Location loc, int argn) {
+        return new Instruction(loc, Type.CALL, argn);
+    }
+    public static Instruction callNew(Location loc, int argn) {
+        return new Instruction(loc, Type.CALL_NEW, argn);
+    }
+    public static Instruction jmp(Location loc, int offset) {
+        return new Instruction(loc, Type.JMP, offset);
+    }
+    public static Instruction jmpIf(Location loc, int offset) {
+        return new Instruction(loc, Type.JMP_IF, offset);
+    }
+    public static Instruction jmpIfNot(Location loc, int offset) {
+        return new Instruction(loc, Type.JMP_IFN, offset);
+    }
+
+    public static Instruction loadValue(Location loc, Object val) {
+        return new Instruction(loc, Type.LOAD_VALUE, val);
+    }
+
+    public static Instruction makeVar(Location loc, String name) {
+        return new Instruction(loc, Type.MAKE_VAR, name);
+    }
+    public static Instruction loadVar(Location loc, Object i) {
+        return new Instruction(loc, Type.LOAD_VAR, i);
+    }
+    public static Instruction loadGlob(Location loc) {
+        return new Instruction(loc, Type.LOAD_GLOB);
+    }
+    public static Instruction loadMember(Location loc) {
+        return new Instruction(loc, Type.LOAD_MEMBER);
+    }
+    public static Instruction loadMember(Location loc, Object key) {
+        if (key instanceof Number) key = ((Number)key).doubleValue();
+        return new Instruction(loc, Type.LOAD_VAL_MEMBER, key);
+    }
+
+    public static Instruction loadRegex(Location loc, String pattern, String flags) {
+        return new Instruction(loc, Type.LOAD_REGEX, pattern, flags);
+    }
+    public static Instruction loadFunc(Location loc, long id, int[] captures) {
+        var args = new Object[1 + captures.length];
+        args[0] = id;
+        for (var i = 0; i < captures.length; i++) args[i + 1] = captures[i];
+        return new Instruction(loc, Type.LOAD_FUNC, args);
+    }
+    public static Instruction loadObj(Location loc) {
+        return new Instruction(loc, Type.LOAD_OBJ);
+    }
+    public static Instruction loadArr(Location loc, int count) {
+        return new Instruction(loc, Type.LOAD_ARR, count);
+    }
+    public static Instruction dup(Location loc) {
+        return new Instruction(loc, Type.DUP, 1);
+    }
+    public static Instruction dup(Location loc, int count) {
+        return new Instruction(loc, Type.DUP, count);
+    }
+
+    public static Instruction storeSelfFunc(Location loc, int i) {
+        return new Instruction(loc, Type.STORE_SELF_FUNC, i);
+    }
+    public static Instruction storeVar(Location loc, Object i) {
+        return new Instruction(loc, Type.STORE_VAR, i, false);
+    }
+    public static Instruction storeVar(Location loc, Object i, boolean keep) {
+        return new Instruction(loc, Type.STORE_VAR, i, keep);
+    }
+    public static Instruction storeMember(Location loc) {
+        return new Instruction(loc, Type.STORE_MEMBER, false);
+    }
+    public static Instruction storeMember(Location loc, boolean keep) {
+        return new Instruction(loc, Type.STORE_MEMBER, keep);
+    }
+    public static Instruction discard(Location loc) {
+        return new Instruction(loc, Type.DISCARD);
+    }
+
+    public static Instruction typeof(Location loc) {
+        return new Instruction(loc, Type.TYPEOF);
+    }
+    public static Instruction typeof(Location loc, Object varName) {
+        return new Instruction(loc, Type.TYPEOF, varName);
+    }
+
+    public static Instruction keys(Location loc, boolean forInFormat) {
+        return new Instruction(loc, Type.KEYS, forInFormat);
+    }
+
+    public static Instruction defProp(Location loc) {
+        return new Instruction(loc, Type.DEF_PROP);
+    }
+
+    public static Instruction operation(Location loc, Operation op) {
+        return new Instruction(loc, Type.OPERATION, op);
+    }
+
+    @Override
+    public String toString() {
+        var res = type.toString();
+
+        for (int i = 0; i < params.length; i++) {
+            res += " " + params[i];
+        }
+
+        return res;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/Statement.java

@@ -0,0 +1,32 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public abstract class Statement {
+    private Location _loc;
+
+    public boolean pure() { return false; }
+    public void declare(ScopeRecord varsScope) { }
+
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType type) {
+        int start = target.size();
+        compile(target, scope, pollute);
+
+        if (target.size() != start) {
+            target.get(start).locate(loc());
+            target.setDebug(start, type);
+        }
+    }
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        compile(target, scope, pollute, BreakpointType.NONE);
+    }
+
+    public Location loc() { return _loc; }
+    public void setLoc(Location loc) { _loc = loc; }
+
+    protected Statement(Location loc) {
+        this._loc = loc;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/ThrowSyntaxStatement.java

@@ -0,0 +1,18 @@
+package me.topchetoeu.jscript.core.compilation;
+
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.core.exceptions.SyntaxException;
+
+public class ThrowSyntaxStatement extends Statement {
+    public final String name;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.throwSyntax(loc(), name));
+    }
+
+    public ThrowSyntaxStatement(SyntaxException e) {
+        super(e.loc);
+        this.name = e.msg;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/VariableDeclareStatement.java

@@ -1,10 +1,11 @@
-package me.topchetoeu.jscript.compilation;
+package me.topchetoeu.jscript.core.compilation;
 
 import java.util.List;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.values.FunctionStatement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.compilation.values.FunctionStatement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
 
 public class VariableDeclareStatement extends Statement {
     public static class Pair {
@@ -32,23 +33,16 @@ public class VariableDeclareStatement extends Statement {
         for (var entry : values) {
             if (entry.name == null) continue;
             var key = scope.getKey(entry.name);
-            int start = target.size();
 
-            if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(entry.location));
+            if (key instanceof String) target.add(Instruction.makeVar(entry.location, (String)key));
 
-            if (entry.value instanceof FunctionStatement) {
-                ((FunctionStatement)entry.value).compile(target, scope, entry.name, false);
-                target.add(Instruction.storeVar(key).locate(entry.location));
+            if (entry.value != null) {
+                FunctionStatement.compileWithName(entry.value, target, scope, true, entry.name, BreakpointType.STEP_OVER);
+                target.add(Instruction.storeVar(entry.location, key));
             }
-            else if (entry.value != null) {
-                entry.value.compile(target, scope, true);
-                target.add(Instruction.storeVar(key).locate(entry.location));
         }
 
-            if (target.size() != start) target.setDebug(start);
-        }
-
-        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
     }
 
     public VariableDeclareStatement(Location loc, List<Pair> values) {

src/java/me/topchetoeu/jscript/core/compilation/control/BreakStatement.java

@@ -0,0 +1,22 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class BreakStatement extends Statement {
+    public final String label;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.nop(loc(), "break", label));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public BreakStatement(Location loc, String label) {
+        super(loc);
+        this.label = label;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/ContinueStatement.java

@@ -0,0 +1,22 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ContinueStatement extends Statement {
+    public final String label;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.nop(loc(), "cont", label));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public ContinueStatement(Location loc, String label) {
+        super(loc);
+        this.label = label;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/DebugStatement.java

@@ -0,0 +1,19 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class DebugStatement extends Statement {
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.debug(loc()));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public DebugStatement(Location loc) {
+        super(loc);
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/DeleteStatement.java

@@ -1,10 +1,10 @@
-package me.topchetoeu.jscript.compilation.control;
+package me.topchetoeu.jscript.core.compilation.control;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
 
 public class DeleteStatement extends Statement {
     public final Statement key;
@@ -15,8 +15,8 @@ public class DeleteStatement extends Statement {
         value.compile(target, scope, true);
         key.compile(target, scope, true);
 
-        target.add(Instruction.delete().locate(loc()));
-        if (!pollute) target.add(Instruction.discard().locate(loc()));
+        target.add(Instruction.delete(loc()));
+        if (pollute) target.add(Instruction.loadValue(loc(), true));
     }
 
     public DeleteStatement(Location loc, Statement key, Statement value) {

src/java/me/topchetoeu/jscript/core/compilation/control/DoWhileStatement.java

@@ -0,0 +1,37 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class DoWhileStatement extends Statement {
+    public final Statement condition, body;
+    public final String label;
+
+    @Override
+    public void declare(ScopeRecord globScope) {
+        body.declare(globScope);
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        int start = target.size();
+        body.compile(target, scope, false, BreakpointType.STEP_OVER);
+        int mid = target.size();
+        condition.compile(target, scope, true, BreakpointType.STEP_OVER);
+        int end = target.size();
+
+        WhileStatement.replaceBreaks(target, label, start, mid - 1, mid, end + 1);
+        target.add(Instruction.jmpIf(loc(), start - end));
+    }
+
+    public DoWhileStatement(Location loc, String label, Statement condition, Statement body) {
+        super(loc);
+        this.label = label;
+        this.condition = condition;
+        this.body = body;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/ForInStatement.java

@@ -0,0 +1,73 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ForInStatement extends Statement {
+    public final String varName;
+    public final boolean isDeclaration;
+    public final Statement varValue, object, body;
+    public final String label;
+    public final Location varLocation;
+
+    @Override
+    public void declare(ScopeRecord globScope) {
+        body.declare(globScope);
+        if (isDeclaration) globScope.define(varName);
+    }
+
+    @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(loc(), (String)key));
+
+        if (varValue != null) {
+            varValue.compile(target, scope, true);
+            target.add(Instruction.storeVar(loc(), scope.getKey(varName)));
+        }
+
+        object.compile(target, scope, true, BreakpointType.STEP_OVER);
+        target.add(Instruction.keys(loc(), true));
+
+        int start = target.size();
+        target.add(Instruction.dup(loc()));
+        target.add(Instruction.loadValue(loc(), null));
+        target.add(Instruction.operation(loc(), Operation.EQUALS));
+        int mid = target.size();
+        target.add(Instruction.nop(loc()));
+
+        target.add(Instruction.loadMember(varLocation, "value"));
+        target.add(Instruction.storeVar(object.loc(), key));
+        target.setDebug(BreakpointType.STEP_OVER);
+
+        body.compile(target, scope, false, BreakpointType.STEP_OVER);
+
+        int end = target.size();
+
+        WhileStatement.replaceBreaks(target, label, mid + 1, end, start, end + 1);
+
+        target.add(Instruction.jmp(loc(), start - end));
+        target.add(Instruction.discard(loc()));
+        target.set(mid, Instruction.jmpIf(loc(), end - mid + 1));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+        target.get(first).locate(loc());
+    }
+
+    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;
+        this.varValue = varValue;
+        this.object = object;
+        this.body = body;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/ForStatement.java

@@ -0,0 +1,47 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ForStatement extends Statement {
+    public final Statement declaration, assignment, condition, body;
+    public final String label;
+
+    @Override
+    public void declare(ScopeRecord globScope) {
+        declaration.declare(globScope);
+        body.declare(globScope);
+    }
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        declaration.compile(target, scope, false, BreakpointType.STEP_OVER);
+
+        int start = target.size();
+        condition.compile(target, scope, true, BreakpointType.STEP_OVER);
+        int mid = target.size();
+        target.add(Instruction.nop(null));
+        body.compile(target, scope, false, BreakpointType.STEP_OVER);
+        int beforeAssign = target.size();
+        assignment.compile(target, scope, false, BreakpointType.STEP_OVER);
+        int end = target.size();
+
+        WhileStatement.replaceBreaks(target, label, mid + 1, end, beforeAssign, end + 1);
+
+        target.add(Instruction.jmp(loc(), start - end));
+        target.set(mid, Instruction.jmpIfNot(loc(), end - mid + 1));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public ForStatement(Location loc, String label, Statement declaration, Statement condition, Statement assignment, Statement body) {
+        super(loc);
+        this.label = label;
+        this.declaration = declaration;
+        this.condition = condition;
+        this.assignment = assignment;
+        this.body = body;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/IfStatement.java

@@ -0,0 +1,52 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class IfStatement extends Statement {
+    public final Statement condition, body, elseBody;
+
+    @Override
+    public void declare(ScopeRecord globScope) {
+        body.declare(globScope);
+        if (elseBody != null) elseBody.declare(globScope);
+    }
+
+    @Override public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType breakpoint) {
+        condition.compile(target, scope, true, breakpoint);
+
+        if (elseBody == null) {
+            int i = target.size();
+            target.add(Instruction.nop(null));
+            body.compile(target, scope, pollute, breakpoint);
+            int endI = target.size();
+            target.set(i, Instruction.jmpIfNot(loc(), endI - i));
+        }
+        else {
+            int start = target.size();
+            target.add(Instruction.nop(null));
+            body.compile(target, scope, pollute, breakpoint);
+            target.add(Instruction.nop(null));
+            int mid = target.size();
+            elseBody.compile(target, scope, pollute, breakpoint);
+            int end = target.size();
+
+            target.set(start, Instruction.jmpIfNot(loc(), mid - start));
+            target.set(mid - 1, Instruction.jmp(loc(), end - mid + 1));
+        }
+    }
+    @Override public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        compile(target, scope, pollute, BreakpointType.STEP_IN);
+    }
+
+    public IfStatement(Location loc, Statement condition, Statement body, Statement elseBody) {
+        super(loc);
+        this.condition = condition;
+        this.body = body;
+        this.elseBody = elseBody;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/ReturnStatement.java

@@ -0,0 +1,23 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ReturnStatement extends Statement {
+    public final Statement value;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        if (value == null) target.add(Instruction.loadValue(loc(), null));
+        else value.compile(target, scope, true);
+        target.add(Instruction.ret(loc()));
+    }
+
+    public ReturnStatement(Location loc, Statement value) {
+        super(loc);
+        this.value = value;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/SwitchStatement.java

@@ -0,0 +1,87 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import java.util.HashMap;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.compilation.Instruction.Type;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class SwitchStatement extends Statement {
+    public static class SwitchCase {
+        public final Statement value;
+        public final int statementI;
+
+        public SwitchCase(Statement value, int statementI) {
+            this.value = value;
+            this.statementI = statementI;
+        }
+    }
+
+    public final Statement value;
+    public final SwitchCase[] cases;
+    public final Statement[] body;
+    public final int defaultI;
+
+    @Override
+    public void declare(ScopeRecord varsScope) {
+        for (var stm : body) stm.declare(varsScope);
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        var caseToStatement = new HashMap<Integer, Integer>();
+        var statementToIndex = new HashMap<Integer, Integer>();
+
+        value.compile(target, scope, true, BreakpointType.STEP_OVER);
+
+        for (var ccase : cases) {
+            target.add(Instruction.dup(loc()));
+            ccase.value.compile(target, scope, true);
+            target.add(Instruction.operation(loc(), Operation.EQUALS));
+            caseToStatement.put(target.size(), ccase.statementI);
+            target.add(Instruction.nop(null));
+        }
+
+        int start = target.size();
+
+        target.add(Instruction.nop(null));
+
+        for (var stm : body) {
+            statementToIndex.put(statementToIndex.size(), target.size());
+            stm.compile(target, scope, false, BreakpointType.STEP_OVER);
+        }
+
+        int end = target.size();
+        target.add(Instruction.discard(loc()));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+
+        if (defaultI < 0 || defaultI >= body.length) target.set(start, Instruction.jmp(loc(), end - start));
+        else target.set(start, Instruction.jmp(loc(), statementToIndex.get(defaultI) - start));
+
+        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(loc(), end - i).locate(instr.location));
+            }
+        }
+        for (var el : caseToStatement.entrySet()) {
+            var i = statementToIndex.get(el.getValue());
+            if (i == null) i = end;
+            target.set(el.getKey(), Instruction.jmpIf(loc(), i - el.getKey()));
+        }
+
+    }
+
+    public SwitchStatement(Location loc, Statement value, int defaultI, SwitchCase[] cases, Statement[] body) {
+        super(loc);
+        this.value = value;
+        this.defaultI = defaultI;
+        this.cases = cases;
+        this.body = body;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/ThrowStatement.java

@@ -0,0 +1,22 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ThrowStatement extends Statement {
+    public final Statement value;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        value.compile(target, scope, true);
+        target.add(Instruction.throwInstr(loc()));
+    }
+
+    public ThrowStatement(Location loc, Statement value) {
+        super(loc);
+        this.value = value;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/control/TryStatement.java

@@ -1,12 +1,13 @@
-package me.topchetoeu.jscript.compilation.control;
+package me.topchetoeu.jscript.core.compilation.control;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.GlobalScope;
-import me.topchetoeu.jscript.engine.scope.LocalScopeRecord;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.GlobalScope;
+import me.topchetoeu.jscript.core.engine.scope.LocalScopeRecord;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
 
 public class TryStatement extends Statement {
     public final Statement tryBody;
@@ -22,31 +23,32 @@ public class TryStatement extends Statement {
     }
 
     @Override
-    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
-        target.add(Instruction.nop());
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType bpt) {
+        target.add(Instruction.nop(null));
 
-        int start = target.size(), tryN, catchN = -1, finN = -1;
+        int start = target.size(), catchStart = -1, finallyStart = -1;
 
         tryBody.compile(target, scope, false);
-        tryN = target.size() - start;
+        target.add(Instruction.tryEnd(loc()));
 
         if (catchBody != null) {
-            int tmp = target.size();
+            catchStart = target.size() - start;
             var local = scope instanceof GlobalScope ? scope.child() : (LocalScopeRecord)scope;
             local.define(name, true);
             catchBody.compile(target, scope, false);
             local.undefine();
-            catchN = target.size() - tmp;
+            target.add(Instruction.tryEnd(loc()));
         }
 
         if (finallyBody != null) {
-            int tmp = target.size();
+            finallyStart = target.size() - start;
             finallyBody.compile(target, scope, false);
-            finN = target.size() - tmp;
+            target.add(Instruction.tryEnd(loc()));
         }
 
-        target.set(start - 1, Instruction.tryInstr(tryN, catchN, finN).locate(loc()));
-        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
+        target.set(start - 1, Instruction.tryStart(loc(), catchStart, finallyStart, target.size() - start));
+        target.setDebug(start - 1, BreakpointType.STEP_OVER);
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
     }
 
     public TryStatement(Location loc, Statement tryBody, Statement catchBody, Statement finallyBody, String name) {

src/java/me/topchetoeu/jscript/core/compilation/control/WhileStatement.java

@@ -0,0 +1,54 @@
+package me.topchetoeu.jscript.core.compilation.control;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.compilation.Instruction.Type;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class WhileStatement extends Statement {
+    public final Statement condition, body;
+    public final String label;
+
+    @Override
+    public void declare(ScopeRecord globScope) {
+        body.declare(globScope);
+    }
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        int start = target.size();
+        condition.compile(target, scope, true);
+        int mid = target.size();
+        target.add(Instruction.nop(null));
+        body.compile(target, scope, false, BreakpointType.STEP_OVER);
+
+        int end = target.size();
+
+        replaceBreaks(target, label, mid + 1, end, start, end + 1);
+
+        target.add(Instruction.jmp(loc(), start - end));
+        target.set(mid, Instruction.jmpIfNot(loc(), end - mid + 1));
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public WhileStatement(Location loc, String label, Statement condition, Statement body) {
+        super(loc);
+        this.label = label;
+        this.condition = condition;
+        this.body = body;
+    }
+
+    public static void replaceBreaks(CompileTarget target, String label, int start, int end, int continuePoint, int breakPoint) {
+        for (int i = start; i < end; i++) {
+            var instr = target.get(i);
+            if (instr.type == Type.NOP && instr.is(0, "cont") && (instr.get(1) == null || instr.is(1, label))) {
+                target.set(i, Instruction.jmp(instr.location, continuePoint - i).setDbgData(target.get(i)));
+            }
+            if (instr.type == Type.NOP && instr.is(0, "break") && (instr.get(1) == null || instr.is(1, label))) {
+                target.set(i, Instruction.jmp(instr.location, breakPoint - i).setDbgData(target.get(i)));
+            }
+        }
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/ArrayStatement.java

@@ -0,0 +1,41 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ArrayStatement extends Statement {
+    public final Statement[] statements;
+
+    @Override public boolean pure() {
+        for (var stm : statements) {
+            if (!stm.pure()) return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.loadArr(loc(), statements.length));
+
+        for (var i = 0; i < statements.length; i++) {
+            var el = statements[i];
+            if (el != null) {
+                target.add(Instruction.dup(loc()));
+                target.add(Instruction.loadValue(loc(), i));
+                el.compile(target, scope, true);
+                target.add(Instruction.storeMember(loc()));
+            }
+        }
+
+        if (!pollute) target.add(Instruction.discard(loc()));
+    }
+
+    public ArrayStatement(Location loc, Statement[] statements) {
+        super(loc);
+        this.statements = statements;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/CallStatement.java

@@ -0,0 +1,51 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class CallStatement extends Statement {
+    public final Statement func;
+    public final Statement[] args;
+    public final boolean isNew;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType type) {
+        if (isNew) func.compile(target, scope, true);
+        else if (func instanceof IndexStatement) {
+            ((IndexStatement)func).compile(target, scope, true, true);
+        }
+        else {
+            target.add(Instruction.loadValue(loc(), null));
+            func.compile(target, scope, true);
+        }
+
+        for (var arg : args) arg.compile(target, scope, true);
+
+        if (isNew) target.add(Instruction.callNew(loc(), args.length));
+        else target.add(Instruction.call(loc(), args.length));
+        target.setDebug(type);
+
+        if (!pollute) target.add(Instruction.discard(loc()));
+    }
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        compile(target, scope, pollute, BreakpointType.STEP_IN);
+    }
+
+    public CallStatement(Location loc, boolean isNew, Statement func, Statement ...args) {
+        super(loc);
+        this.isNew = isNew;
+        this.func = func;
+        this.args = args;
+    }
+    public CallStatement(Location loc, boolean isNew, Statement obj, Object key, Statement ...args) {
+        super(loc);
+        this.isNew = isNew;
+        this.func = new IndexStatement(loc, obj, new ConstantStatement(loc, key));
+        this.args = args;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/ChangeStatement.java

@@ -0,0 +1,32 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.AssignableStatement;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ChangeStatement extends Statement {
+    public final AssignableStatement value;
+    public final double addAmount;
+    public final boolean postfix;
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        value.toAssign(new ConstantStatement(loc(), -addAmount), Operation.SUBTRACT).compile(target, scope, true);
+        if (!pollute) target.add(Instruction.discard(loc()));
+        else if (postfix) {
+            target.add(Instruction.loadValue(loc(), addAmount));
+            target.add(Instruction.operation(loc(), Operation.SUBTRACT));
+        }
+    }
+
+    public ChangeStatement(Location loc, AssignableStatement value, double addAmount, boolean postfix) {
+        super(loc);
+        this.value = value;
+        this.addAmount = addAmount;
+        this.postfix = postfix;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/ConstantStatement.java

@@ -0,0 +1,23 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ConstantStatement extends Statement {
+    public final Object value;
+
+    @Override public boolean pure() { return true; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        if (pollute) target.add(Instruction.loadValue(loc(), value));
+    }
+
+    public ConstantStatement(Location loc, Object val) {
+        super(loc);
+        this.value = val;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/DiscardStatement.java

@@ -0,0 +1,24 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class DiscardStatement extends Statement {
+    public final Statement value;
+
+    @Override public boolean pure() { return value.pure(); }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        value.compile(target, scope, false);
+        if (pollute) target.add(Instruction.loadValue(loc(), null));
+    }
+
+    public DiscardStatement(Location loc, Statement val) {
+        super(loc);
+        this.value = val;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/FunctionStatement.java

@@ -0,0 +1,139 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import java.util.Random;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.CompoundStatement;
+import me.topchetoeu.jscript.core.compilation.FunctionBody;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.compilation.Instruction.Type;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.core.exceptions.SyntaxException;
+
+public class FunctionStatement extends Statement {
+    public final CompoundStatement body;
+    public final String varName;
+    public final String[] args;
+    public final boolean statement;
+    public final Location end;
+
+    private static Random rand = new Random();
+
+    @Override public boolean pure() { return varName == null && statement; }
+
+    @Override
+    public void declare(ScopeRecord scope) {
+        if (varName != null && statement) scope.define(varName);
+    }
+
+    public static void checkBreakAndCont(CompileTarget target, int start) {
+        for (int i = start; i < target.size(); i++) {
+            if (target.get(i).type == Type.NOP) {
+                if (target.get(i).is(0, "break") ) {
+                    throw new SyntaxException(target.get(i).location, "Break was placed outside a loop.");
+                }
+                if (target.get(i).is(0, "cont")) {
+                    throw new SyntaxException(target.get(i).location, "Continue was placed outside a loop.");
+                }
+            }
+        }
+    }
+
+    private long compileBody(CompileTarget target, ScopeRecord scope, boolean polute, BreakpointType bp) {
+        for (var i = 0; i < args.length; i++) {
+            for (var j = 0; j < i; j++) {
+                if (args[i].equals(args[j])) {
+                    throw new SyntaxException(loc(), "Duplicate parameter '" + args[i] + "'.");
+                }
+            }
+        }
+
+        var id = rand.nextLong();
+        var subscope = scope.child();
+        var subtarget = new CompileTarget(target.functions, target.breakpoints);
+
+        subscope.define("this");
+        var argsVar = subscope.define("arguments");
+
+        if (args.length > 0) {
+            for (var i = 0; i < args.length; i++) {
+                subtarget.add(Instruction.loadVar(loc(), argsVar));
+                subtarget.add(Instruction.loadMember(loc(), i));
+                subtarget.add(Instruction.storeVar(loc(), subscope.define(args[i])));
+            }
+        }
+
+        if (!statement && this.varName != null) {
+            subtarget.add(Instruction.storeSelfFunc(loc(), (int)subscope.define(this.varName)));
+            subtarget.setDebug(bp);
+        }
+
+        body.declare(subscope);
+        body.compile(subtarget, subscope, false);
+        subtarget.add(Instruction.ret(end));
+        checkBreakAndCont(subtarget, 0);
+
+        if (polute) target.add(Instruction.loadFunc(loc(), id, subscope.getCaptures()));
+        target.functions.put(id, new FunctionBody(
+            subscope.localsCount(), args.length,
+            subtarget.array(), subscope.captures(), subscope.locals()
+        ));
+
+        return id;
+    }
+
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, String name, BreakpointType bp) {
+        if (this.varName != null) name = this.varName;
+
+        var hasVar = this.varName != null && statement;
+        var hasName = name != null;
+
+        compileBody(target, scope, pollute || hasVar || hasName, bp);
+
+        if (hasName) {
+            if (pollute || hasVar) target.add(Instruction.dup(loc()));
+            target.add(Instruction.loadValue(loc(), "name"));
+            target.add(Instruction.loadValue(loc(), name));
+            target.add(Instruction.storeMember(loc()));
+        }
+
+        if (hasVar) {
+            var key = scope.getKey(this.varName);
+
+            if (key instanceof String) target.add(Instruction.makeVar(loc(), (String)key));
+            target.add(Instruction.storeVar(loc(), scope.getKey(this.varName), false));
+        }
+    }
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, String name) {
+        compile(target, scope, pollute, name, BreakpointType.NONE);
+    }
+    @Override public void compile(CompileTarget target, ScopeRecord scope, boolean pollute, BreakpointType bp) {
+        compile(target, scope, pollute, (String)null, bp);
+    }
+    @Override public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        compile(target, scope, pollute, (String)null, BreakpointType.NONE);
+    }
+
+    public FunctionStatement(Location loc, Location end, String varName, String[] args, boolean statement, CompoundStatement body) {
+        super(loc);
+
+        this.end = end;
+        this.varName = varName;
+        this.statement = statement;
+
+        this.args = args;
+        this.body = body;
+    }
+
+    public static void compileWithName(Statement stm, CompileTarget target, ScopeRecord scope, boolean pollute, String name) {
+        if (stm instanceof FunctionStatement) ((FunctionStatement)stm).compile(target, scope, pollute, name);
+        else stm.compile(target, scope, pollute);
+    }
+    public static void compileWithName(Statement stm, CompileTarget target, ScopeRecord scope, boolean pollute, String name, BreakpointType bp) {
+        if (stm instanceof FunctionStatement) ((FunctionStatement)stm).compile(target, scope, pollute, name, bp);
+        else stm.compile(target, scope, pollute, bp);
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/GlobalThisStatement.java

@@ -0,0 +1,20 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class GlobalThisStatement extends Statement {
+    @Override public boolean pure() { return true; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        if (pollute) target.add(Instruction.loadGlob(loc()));
+    }
+
+    public GlobalThisStatement(Location loc) {
+        super(loc);
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/IndexAssignStatement.java

@@ -1,11 +1,12 @@
-package me.topchetoeu.jscript.compilation.values;
+package me.topchetoeu.jscript.core.compilation.values;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.Operation;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
 
 public class IndexAssignStatement extends Statement {
     public final Statement object;
@@ -18,22 +19,22 @@ public class IndexAssignStatement extends Statement {
         if (operation != null) {
             object.compile(target, scope, true);
             index.compile(target, scope, true);
-            target.add(Instruction.dup(2, 0).locate(loc()));
+            target.add(Instruction.dup(loc(), 2));
 
-            target.add(Instruction.loadMember().locate(loc()));
+            target.add(Instruction.loadMember(loc()));
             value.compile(target, scope, true);
-            target.add(Instruction.operation(operation).locate(loc()));
+            target.add(Instruction.operation(loc(), operation));
 
-            target.add(Instruction.storeMember(pollute).locate(loc()));
-            target.setDebug();
+            target.add(Instruction.storeMember(loc(), pollute));
+            target.setDebug(BreakpointType.STEP_IN);
         }
         else {
             object.compile(target, scope, true);
             index.compile(target, scope, true);
             value.compile(target, scope, true);
 
-            target.add(Instruction.storeMember(pollute).locate(loc()));
-            target.setDebug();
+            target.add(Instruction.storeMember(loc(), pollute));
+            target.setDebug(BreakpointType.STEP_IN);
         }
     }
 

src/java/me/topchetoeu/jscript/core/compilation/values/IndexStatement.java

@@ -1,37 +1,35 @@
-package me.topchetoeu.jscript.compilation.values;
+package me.topchetoeu.jscript.core.compilation.values;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.AssignableStatement;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.Operation;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.AssignableStatement;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.compilation.Instruction.BreakpointType;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
 
 public class IndexStatement extends AssignableStatement {
     public final Statement object;
     public final Statement index;
 
-    @Override
-    public boolean pure() { return true; }
-
     @Override
     public Statement toAssign(Statement val, Operation operation) {
         return new IndexAssignStatement(loc(), object, index, val, operation);
     }
     public void compile(CompileTarget target, ScopeRecord scope, boolean dupObj, boolean pollute) {
         object.compile(target, scope, true);
-        if (dupObj) target.add(Instruction.dup().locate(loc()));
+        if (dupObj) target.add(Instruction.dup(loc()));
         if (index instanceof ConstantStatement) {
-            target.add(Instruction.loadMember(((ConstantStatement)index).value).locate(loc()));
-            target.setDebug();
+            target.add(Instruction.loadMember(loc(), ((ConstantStatement)index).value));
+            target.setDebug(BreakpointType.STEP_IN);
             return;
         }
 
         index.compile(target, scope, true);
-        target.add(Instruction.loadMember().locate(loc()));
-        target.setDebug();
-        if (!pollute) target.add(Instruction.discard().locate(loc()));
+        target.add(Instruction.loadMember(loc()));
+        target.setDebug(BreakpointType.STEP_IN);
+        if (!pollute) target.add(Instruction.discard(loc()));
     }
     @Override
     public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {

src/java/me/topchetoeu/jscript/core/compilation/values/LazyAndStatement.java

@@ -1,19 +1,16 @@
-package me.topchetoeu.jscript.compilation.values;
+package me.topchetoeu.jscript.core.compilation.values;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.core.engine.values.Values;
 
 public class LazyAndStatement extends Statement {
     public final Statement first, second;
 
-    @Override
-    public boolean pure() {
-        return first.pure() && second.pure();
-    }
+    @Override public boolean pure() { return first.pure() && second.pure(); }
 
     @Override
     public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
@@ -26,12 +23,12 @@ public class LazyAndStatement extends Statement {
         }
 
         first.compile(target, scope, true);
-        if (pollute) target.add(Instruction.dup().locate(loc()));
+        if (pollute) target.add(Instruction.dup(loc()));
         int start = target.size();
-        target.add(Instruction.nop());
-        target.add(Instruction.discard().locate(loc()));
+        target.add(Instruction.nop(null));
+        if (pollute) target.add(Instruction.discard(loc()));
         second.compile(target, scope, pollute);
-        target.set(start, Instruction.jmpIfNot(target.size() - start).locate(loc()));
+        target.set(start, Instruction.jmpIfNot(loc(), target.size() - start));
     }
 
     public LazyAndStatement(Location loc, Statement first, Statement second) {

src/java/me/topchetoeu/jscript/core/compilation/values/LazyOrStatement.java

@@ -1,19 +1,16 @@
-package me.topchetoeu.jscript.compilation.values;
+package me.topchetoeu.jscript.core.compilation.values;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.CompileTarget;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.core.engine.values.Values;
 
 public class LazyOrStatement extends Statement {
     public final Statement first, second;
 
-    @Override
-    public boolean pure() {
-        return first.pure() && second.pure();
-    }
+    @Override public boolean pure() { return first.pure() && second.pure(); }
 
     @Override
     public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
@@ -26,12 +23,12 @@ public class LazyOrStatement extends Statement {
         }
 
         first.compile(target, scope, true);
-        if (pollute) target.add(Instruction.dup().locate(loc()));
+        if (pollute) target.add(Instruction.dup(loc()));
         int start = target.size();
-        target.add(Instruction.nop());
-        target.add(Instruction.discard().locate(loc()));
+        target.add(Instruction.nop(null));
+        if (pollute) target.add(Instruction.discard(loc()));
         second.compile(target, scope, pollute);
-        target.set(start, Instruction.jmpIf(target.size() - start).locate(loc()));
+        target.set(start, Instruction.jmpIf(loc(), target.size() - start));
     }
 
     public LazyOrStatement(Location loc, Statement first, Statement second) {

src/java/me/topchetoeu/jscript/core/compilation/values/ObjectStatement.java

@@ -0,0 +1,63 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import java.util.ArrayList;
+import java.util.Map;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class ObjectStatement extends Statement {
+    public final Map<Object, Statement> map;
+    public final Map<Object, FunctionStatement> getters;
+    public final Map<Object, FunctionStatement> setters;
+
+    @Override public boolean pure() {
+        for (var el : map.values()) {
+            if (!el.pure()) return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.loadObj(loc()));
+
+        for (var el : map.entrySet()) {
+            target.add(Instruction.dup(loc()));
+            target.add(Instruction.loadValue(loc(), el.getKey()));
+            var val = el.getValue();
+            FunctionStatement.compileWithName(val, target, scope, true, el.getKey().toString());
+            target.add(Instruction.storeMember(loc()));
+        }
+
+        var keys = new ArrayList<Object>();
+        keys.addAll(getters.keySet());
+        keys.addAll(setters.keySet());
+
+        for (var key : keys) {
+            if (key instanceof String) target.add(Instruction.loadValue(loc(), (String)key));
+            else target.add(Instruction.loadValue(loc(), (Double)key));
+
+            if (getters.containsKey(key)) getters.get(key).compile(target, scope, true);
+            else target.add(Instruction.loadValue(loc(), null));
+
+            if (setters.containsKey(key)) setters.get(key).compile(target, scope, true);
+            else target.add(Instruction.loadValue(loc(), null));
+
+            target.add(Instruction.defProp(loc()));
+        }
+
+        if (!pollute) target.add(Instruction.discard(loc()));
+    }
+
+    public ObjectStatement(Location loc, Map<Object, Statement> map, Map<Object, FunctionStatement> getters, Map<Object, FunctionStatement> setters) {
+        super(loc);
+        this.map = map;
+        this.getters = getters;
+        this.setters = setters;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/OperationStatement.java

@@ -0,0 +1,37 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class OperationStatement extends Statement {
+    public final Statement[] args;
+    public final Operation operation;
+
+    @Override public boolean pure() {
+        for (var el : args) {
+            if (!el.pure()) return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        for (var arg : args) {
+            arg.compile(target, scope, true);
+        }
+
+        if (pollute) target.add(Instruction.operation(loc(), operation));
+        else target.add(Instruction.discard(loc()));
+    }
+
+    public OperationStatement(Location loc, Operation operation, Statement ...args) {
+        super(loc);
+        this.operation = operation;
+        this.args = args;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/RegexStatement.java

@@ -0,0 +1,26 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class RegexStatement extends Statement {
+    public final String pattern, flags;
+
+    // Not really pure, since a function is called, but can be ignored.
+    @Override public boolean pure() { return true; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        target.add(Instruction.loadRegex(loc(), pattern, flags));
+        if (!pollute) target.add(Instruction.discard(loc()));
+    }
+
+    public RegexStatement(Location loc, String pattern, String flags) {
+        super(loc);
+        this.pattern = pattern;
+        this.flags = flags;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/TypeofStatement.java

@@ -0,0 +1,33 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class TypeofStatement extends Statement {
+    public final Statement value;
+
+    // Not really pure, since a variable from the global scope could be accessed,
+    // which could lead to code execution, that would get omitted
+    @Override public boolean pure() { return true; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        if (value instanceof VariableStatement) {
+            var i = scope.getKey(((VariableStatement)value).name);
+            if (i instanceof String) {
+                target.add(Instruction.typeof(loc(), (String)i));
+                return;
+            }
+        }
+        value.compile(target, scope, pollute);
+        target.add(Instruction.typeof(loc()));
+    }
+
+    public TypeofStatement(Location loc, Statement value) {
+        super(loc);
+        this.value = value;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/VariableAssignStatement.java

@@ -0,0 +1,38 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class VariableAssignStatement extends Statement {
+    public final String name;
+    public final Statement value;
+    public final Operation operation;
+
+    @Override public boolean pure() { return false; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        var i = scope.getKey(name);
+        if (operation != null) {
+            target.add(Instruction.loadVar(loc(), i));
+            FunctionStatement.compileWithName(value, target, scope, true, name);
+            target.add(Instruction.operation(loc(), operation));
+            target.add(Instruction.storeVar(loc(), i, pollute));
+        }
+        else {
+            FunctionStatement.compileWithName(value, target, scope, true, name);
+            target.add(Instruction.storeVar(loc(), i, pollute));
+        }
+    }
+
+    public VariableAssignStatement(Location loc, String name, Statement val, Operation operation) {
+        super(loc);
+        this.name = name;
+        this.value = val;
+        this.operation = operation;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/VariableIndexStatement.java

@@ -0,0 +1,23 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class VariableIndexStatement extends Statement {
+    public final int index;
+
+    @Override public boolean pure() { return true; }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        if (pollute) target.add(Instruction.loadVar(loc(), index));
+    }
+
+    public VariableIndexStatement(Location loc, int i) {
+        super(loc);
+        this.index = i;
+    }
+}

src/java/me/topchetoeu/jscript/core/compilation/values/VariableStatement.java

@@ -0,0 +1,32 @@
+package me.topchetoeu.jscript.core.compilation.values;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.AssignableStatement;
+import me.topchetoeu.jscript.core.compilation.CompileTarget;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.compilation.Statement;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ScopeRecord;
+
+public class VariableStatement extends AssignableStatement {
+    public final String name;
+
+    @Override public boolean pure() { return false; }
+
+    @Override
+    public Statement toAssign(Statement val, Operation operation) {
+        return new VariableAssignStatement(loc(), name, val, operation);
+    }
+
+    @Override
+    public void compile(CompileTarget target, ScopeRecord scope, boolean pollute) {
+        var i = scope.getKey(name);
+        target.add(Instruction.loadVar(loc(), i));
+        if (!pollute) target.add(Instruction.discard(loc()));
+    }
+
+    public VariableStatement(Location loc, String name) {
+        super(loc);
+        this.name = name;
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/Context.java

@@ -0,0 +1,166 @@
+package me.topchetoeu.jscript.core.engine;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.engine.debug.DebugContext;
+import me.topchetoeu.jscript.core.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.core.engine.values.ArrayValue;
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.lib.EnvironmentLib;
+import me.topchetoeu.jscript.utils.mapping.SourceMap;
+
+public class Context implements Extensions {
+    public static final Context NULL = new Context(null);
+
+    public final Context parent;
+    public final Environment environment;
+    public final CodeFrame frame;
+    public final Engine engine;
+    public final int stackSize;
+
+    @Override public <T> void add(Symbol key, T obj) {
+        if (environment != null) environment.add(key, obj);
+        else if (engine != null) engine.add(key, obj);
+    }
+    @Override public <T> T get(Symbol key) {
+        if (environment != null && environment.has(key)) return environment.get(key);
+        else if (engine != null && engine.has(key)) return engine.get(key);
+        return null;
+    }
+    @Override public boolean has(Symbol key) {
+        return
+            environment != null && environment.has(key) ||
+            engine != null && engine.has(key);
+    }
+    @Override public boolean remove(Symbol key) {
+        var res = false;
+
+        if (environment != null) res |= environment.remove(key);
+        else if (engine != null) res |= engine.remove(key);
+
+        return res;
+    }
+    @Override public Iterable<Symbol> keys() {
+        if (engine == null && environment == null) return List.of();
+        if (engine == null) return environment.keys();
+        if (environment == null) return engine.keys();
+
+        return () -> Stream.concat(
+            StreamSupport.stream(engine.keys().spliterator(), false),
+            StreamSupport.stream(environment.keys().spliterator(), false)
+        ).distinct().iterator();
+    }
+
+    public FunctionValue compile(Filename filename, String raw) {
+        var env = environment;
+        var result = Environment.compileFunc(this).call(this, null, raw, filename.toString(), new EnvironmentLib(env));
+
+        var function = (FunctionValue)Values.getMember(this, result, "function");
+        if (!DebugContext.enabled(this)) return function;
+
+        var rawMapChain = ((ArrayValue)Values.getMember(this, result, "mapChain")).toArray();
+        var breakpoints = new TreeSet<>(
+            Arrays.stream(((ArrayValue)Values.getMember(this, result, "breakpoints")).toArray())
+                .map(v -> Location.parse(Values.toString(this, v)))
+                .collect(Collectors.toList())
+        );
+        var maps = new SourceMap[rawMapChain.length];
+
+        for (var i = 0; i < maps.length; i++) maps[i] = SourceMap.parse(Values.toString(this, (String)rawMapChain[i]));
+
+        var map = SourceMap.chain(maps);
+
+        if (map != null) {
+            var newBreakpoints = new TreeSet<Location>();
+            for (var bp : breakpoints) {
+                bp = map.toCompiled(bp);
+                if (bp != null) newBreakpoints.add(bp);
+            }
+            breakpoints = newBreakpoints;
+        }
+
+        DebugContext.get(this).onSource(filename, raw, breakpoints, map);
+
+        return function;
+    }
+
+    public Context pushFrame(CodeFrame frame) {
+        var res = new Context(this, frame.function.environment, frame, engine, stackSize + 1);
+        return res;
+    }
+
+    public Iterable<CodeFrame> frames() {
+        var self = this;
+        return () -> new Iterator<CodeFrame>() {
+            private Context curr = self;
+
+            private void update() {
+                while (curr != null && curr.frame == null) curr = curr.parent;
+            }
+
+            @Override public boolean hasNext() {
+                update();
+                return curr != null;
+            }
+            @Override public CodeFrame next() {
+                update();
+                var res = curr.frame;
+                curr = curr.parent;
+                return res;
+            }
+        };
+    }
+    public List<String> stackTrace() {
+        var res = new ArrayList<String>();
+
+        for (var el : frames()) {
+            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;
+    }
+
+    private Context(Context parent, Environment environment, CodeFrame frame, Engine engine, int stackSize) {
+        this.parent = parent;
+        this.environment = environment;
+        this.frame = frame;
+        this.engine = engine;
+        this.stackSize = stackSize;
+
+        if (hasNotNull(Environment.MAX_STACK_COUNT) && stackSize > (int)get(Environment.MAX_STACK_COUNT)) {
+            throw EngineException.ofRange("Stack overflow!");
+        }
+    }
+
+    public Context(Engine engine) {
+        this(null, null, null, engine, 0);
+    }
+    public Context(Engine engine, Environment env) {
+        this(null, env, null, engine, 0);
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/Engine.java

@@ -0,0 +1,57 @@
+package me.topchetoeu.jscript.core.engine;
+
+import java.util.HashMap;
+
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.common.events.Awaitable;
+import me.topchetoeu.jscript.core.compilation.FunctionBody;
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+
+public class Engine extends EventLoop implements Extensions {
+    public static final HashMap<Long, FunctionBody> functions = new HashMap<>();
+
+    private final Environment env = new Environment();
+
+    @Override
+    public <T> void add(Symbol key, T obj) {
+        this.env.add(key, obj);
+    }
+    @Override
+    public <T> T get(Symbol key) {
+        return this.env.get(key);
+    }
+    @Override
+    public boolean has(Symbol key) {
+        return this.env.has(key);
+    }
+    @Override
+    public boolean remove(Symbol key) {
+        return this.env.remove(key);
+    }
+    @Override
+    public Iterable<Symbol> keys() {
+        return env.keys();
+    }
+
+    public Engine copy() {
+        var res = new Engine();
+        res.env.addAll(env);
+        return res;
+    }
+
+    public Awaitable<Object> pushMsg(boolean micro, Environment env, FunctionValue func, Object thisArg, Object ...args) {
+        return pushMsg(() -> {
+            return func.call(new Context(this, env), thisArg, args);
+        }, micro);
+    }
+    public Awaitable<Object> pushMsg(boolean micro, Environment env, Filename filename, String raw, Object thisArg, Object ...args) {
+        return pushMsg(() -> {
+            var ctx = new Context(this, env);
+            return ctx.compile(filename, raw).call(new Context(this, env), thisArg, args);
+        }, micro);
+    }
+
+    public Engine() {
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/Environment.java

@@ -0,0 +1,128 @@
+package me.topchetoeu.jscript.core.engine;
+
+import java.util.HashMap;
+import java.util.stream.Collectors;
+
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.engine.debug.DebugContext;
+import me.topchetoeu.jscript.core.engine.scope.GlobalScope;
+import me.topchetoeu.jscript.core.engine.values.ArrayValue;
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.NativeFunction;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.core.parsing.Parsing;
+import me.topchetoeu.jscript.utils.interop.NativeWrapperProvider;
+
+@SuppressWarnings("unchecked")
+public class Environment implements Extensions {
+
+    public static final HashMap<String, Symbol> symbols = new HashMap<>();
+
+    public static final Symbol WRAPPERS = Symbol.get("Environment.wrappers");
+    public static final Symbol COMPILE_FUNC = Symbol.get("Environment.compile");
+
+    public static final Symbol REGEX_CONSTR = Symbol.get("Environment.regexConstructor");
+    public static final Symbol STACK = Symbol.get("Environment.stack");
+    public static final Symbol MAX_STACK_COUNT = Symbol.get("Environment.maxStackCount");
+    public static final Symbol HIDE_STACK = Symbol.get("Environment.hideStack");
+
+    public static final Symbol OBJECT_PROTO = Symbol.get("Environment.objectPrototype");
+    public static final Symbol FUNCTION_PROTO = Symbol.get("Environment.functionPrototype");
+    public static final Symbol ARRAY_PROTO = Symbol.get("Environment.arrayPrototype");
+    public static final Symbol BOOL_PROTO = Symbol.get("Environment.boolPrototype");
+    public static final Symbol NUMBER_PROTO = Symbol.get("Environment.numberPrototype");
+    public static final Symbol STRING_PROTO = Symbol.get("Environment.stringPrototype");
+    public static final Symbol SYMBOL_PROTO = Symbol.get("Environment.symbolPrototype");
+    public static final Symbol ERROR_PROTO = Symbol.get("Environment.errorPrototype");
+    public static final Symbol SYNTAX_ERR_PROTO = Symbol.get("Environment.syntaxErrorPrototype");
+    public static final Symbol TYPE_ERR_PROTO = Symbol.get("Environment.typeErrorPrototype");
+    public static final Symbol RANGE_ERR_PROTO = Symbol.get("Environment.rangeErrorPrototype");
+
+    private HashMap<Symbol, Object> data = new HashMap<>();
+
+    public GlobalScope global;
+    public WrapperProvider wrappers;
+
+    @Override public <T> void add(Symbol key, T obj) {
+        data.put(key, obj);
+    }
+    @Override public <T> T get(Symbol key) {
+        return (T)data.get(key);
+    }
+    @Override public boolean remove(Symbol key) {
+        if (data.containsKey(key)) {
+            data.remove(key);
+            return true;
+        }
+        return false;
+    }
+    @Override public boolean has(Symbol key) {
+        return data.containsKey(key);
+    }
+    @Override public Iterable<Symbol> keys() {
+        return data.keySet();
+    }
+
+    public static FunctionValue compileFunc(Extensions ext) {
+        return ext.init(COMPILE_FUNC, new NativeFunction("compile", args -> {
+            var source = args.getString(0);
+            var filename = args.getString(1);
+            var env = Values.wrapper(Values.getMember(args.ctx, args.get(2), Symbol.get("env")), Environment.class);
+            var isDebug = DebugContext.enabled(args.ctx);
+            var res = new ObjectValue();
+
+            var target = Parsing.compile(env, Filename.parse(filename), source);
+            Engine.functions.putAll(target.functions);
+            Engine.functions.remove(0l);
+
+            res.defineProperty(args.ctx, "function", target.func(env));
+            res.defineProperty(args.ctx, "mapChain", new ArrayValue());
+
+            if (isDebug) res.defineProperty(
+                args.ctx, "breakpoints",
+                ArrayValue.of(args.ctx, target.breakpoints.stream().map(Location::toString).collect(Collectors.toList()))
+            );
+
+            return res;
+        }));
+    }
+    public static FunctionValue regexConstructor(Extensions ext) {
+        return ext.init(COMPILE_FUNC, new NativeFunction("RegExp", args -> {
+            throw EngineException.ofError("Regular expressions not supported.").setCtx(args.ctx.environment, args.ctx.engine);
+        }));
+    }
+
+    public Environment copy() {
+        var res = new Environment(null, global);
+
+        res.wrappers = wrappers.fork(res);
+        res.global = global;
+        res.data.putAll(data);
+
+        return res;
+    }
+    public Environment child() {
+        var res = copy();
+        res.global = res.global.globalChild();
+        return res;
+    }
+
+    public Context context(Engine engine) {
+        return new Context(engine, this);
+    }
+
+    public Environment(WrapperProvider nativeConverter, GlobalScope global) {
+        if (nativeConverter == null) nativeConverter = new NativeWrapperProvider(this);
+        if (global == null) global = new GlobalScope();
+
+        this.wrappers = nativeConverter;
+        this.global = global;
+    }
+    public Environment() {
+        this(null, null);
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/EventLoop.java

@@ -0,0 +1,81 @@
+package me.topchetoeu.jscript.core.engine;
+
+import java.util.concurrent.PriorityBlockingQueue;
+
+import me.topchetoeu.jscript.common.ResultRunnable;
+import me.topchetoeu.jscript.common.events.Awaitable;
+import me.topchetoeu.jscript.common.events.DataNotifier;
+import me.topchetoeu.jscript.core.exceptions.InterruptException;
+
+public class EventLoop {
+    private static class Task implements Comparable<Task> {
+        public final ResultRunnable<?> runnable;
+        public final DataNotifier<Object> notifier = new DataNotifier<>();
+        public final boolean micro;
+
+        public Task(ResultRunnable<?> runnable, boolean micro) {
+            this.runnable = runnable;
+            this.micro = micro;
+        }
+
+        @Override
+        public int compareTo(Task other) {
+            return Integer.compare(this.micro ? 0 : 1, other.micro ? 0 : 1);
+        }
+    }
+
+    private PriorityBlockingQueue<Task> tasks = new PriorityBlockingQueue<>();
+    private Thread thread;
+
+    @SuppressWarnings("unchecked")
+    public <T> Awaitable<T> pushMsg(ResultRunnable<T> runnable, boolean micro) {
+        var msg = new Task(runnable, micro);
+        tasks.add(msg);
+        return (Awaitable<T>)msg.notifier;
+    }
+    public Awaitable<Object> pushMsg(Runnable runnable, boolean micro) {
+        return pushMsg(() -> { runnable.run(); return null; }, micro);
+    }
+
+    public void run(boolean untilEmpty) {
+        while (!untilEmpty || !tasks.isEmpty()) {
+            try {
+                var task = tasks.take();
+
+                try {
+                    task.notifier.next(task.runnable.run());
+                }
+                catch (RuntimeException e) {
+                    if (e instanceof InterruptException) throw e;
+                    task.notifier.error(e);
+                }
+            }
+            catch (InterruptedException | InterruptException e) {
+                for (var msg : tasks) msg.notifier.error(new InterruptException(e));
+                break;
+            }
+        }
+    }
+
+    public Thread thread() {
+        return thread;
+    }
+    public Thread start() {
+        if (thread == null) {
+            thread = new Thread(() -> run(false), "Event loop #" + hashCode());
+            thread.start();
+        }
+        return thread;
+    }
+    public void stop() {
+        if (thread != null) thread.interrupt();
+        thread = null;
+    }
+
+    public boolean inLoopThread() {
+        return Thread.currentThread() == thread;
+    }
+    public boolean isRunning() {
+        return this.thread != null;
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/Extensions.java

@@ -0,0 +1,34 @@
+package me.topchetoeu.jscript.core.engine;
+
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+
+public interface Extensions {
+    <T> T get(Symbol key);
+    <T> void add(Symbol key, T obj);
+    Iterable<Symbol> keys();
+
+    boolean has(Symbol key);
+    boolean remove(Symbol key);
+
+    default boolean hasNotNull(Symbol key) {
+        return has(key) && get(key) != null;
+    }
+
+    default <T> T get(Symbol key, T defaultVal) {
+        if (has(key)) return get(key);
+        else return defaultVal;
+    }
+
+    default <T> T init(Symbol key, T val) {
+        if (has(key)) return get(key);
+        else {
+            add(key, val);
+            return val;
+        }
+    }
+    default void addAll(Extensions source) {
+        for (var key : source.keys()) {
+            add(key, source.get(key));
+        }
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/Operation.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.engine;
+package me.topchetoeu.jscript.core.engine;
 
 public enum Operation {
     INSTANCEOF(2, false),

src/java/me/topchetoeu/jscript/core/engine/WrapperProvider.java

@@ -0,0 +1,12 @@
+package me.topchetoeu.jscript.core.engine;
+
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+
+public interface WrapperProvider {
+    public ObjectValue getProto(Class<?> obj);
+    public ObjectValue getNamespace(Class<?> obj);
+    public FunctionValue getConstr(Class<?> obj);
+
+    public WrapperProvider fork(Environment env);
+}

src/java/me/topchetoeu/jscript/core/engine/debug/DebugContext.java

@@ -0,0 +1,100 @@
+package me.topchetoeu.jscript.core.engine.debug;
+
+import java.util.HashMap;
+import java.util.TreeSet;
+
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Extensions;
+import me.topchetoeu.jscript.core.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.utils.mapping.SourceMap;
+
+public class DebugContext implements DebugController {
+    public static final Symbol ENV_KEY = Symbol.get("Engine.debug");
+    public static final Symbol IGNORE = Symbol.get("Engine.ignoreDebug");
+
+    private HashMap<Filename, String> sources;
+    private HashMap<Filename, TreeSet<Location>> bpts;
+    private HashMap<Filename, SourceMap> maps;
+    private DebugController debugger;
+
+    public boolean attachDebugger(DebugController debugger) {
+        if (this.debugger != null) return false;
+
+        if (sources != null) {
+            for (var source : sources.entrySet()) debugger.onSource(
+                source.getKey(), source.getValue(),
+                bpts.get(source.getKey()),
+                maps.get(source.getKey())
+            );
+        }
+
+        this.debugger = debugger;
+        return true;
+    }
+    public boolean detachDebugger() {
+        this.debugger = null;
+        return true;
+    }
+
+    public DebugController debugger() {
+        if (debugger == null) return DebugController.empty();
+        else return debugger;
+    }
+
+    @Override public void onFramePop(Context ctx, CodeFrame frame) {
+        if (debugger != null) debugger.onFramePop(ctx, frame);
+    }
+    @Override public void onFramePush(Context ctx, CodeFrame frame) {
+        if (debugger != null) debugger.onFramePush(ctx, frame);
+    }
+    @Override public boolean onInstruction(Context ctx, CodeFrame frame, Instruction instruction, Object returnVal, EngineException error, boolean caught) {
+        if (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, SourceMap map) {
+        if (debugger != null) debugger.onSource(filename, source, breakpoints, map);
+        if (sources != null) sources.put(filename, source);
+        if (bpts != null) bpts.put(filename, breakpoints);
+        if (maps != null) maps.put(filename, map);
+    }
+
+    public Location mapToCompiled(Location location) {
+        if (maps == null) return location;
+
+        var map = maps.get(location.filename());
+        if (map == null) return location;
+        return map.toCompiled(location);
+    }
+    public Location mapToOriginal(Location location) {
+        if (maps == null) return location;
+
+        var map = maps.get(location.filename());
+        if (map == null) return location;
+        return map.toOriginal(location);
+    }
+
+    private DebugContext(boolean enabled) {
+        if (enabled) {
+            sources = new HashMap<>();
+            bpts = new HashMap<>();
+            maps = new HashMap<>();
+        }
+    }
+
+    public DebugContext() {
+        this(true);
+    }
+
+    public static boolean enabled(Extensions exts) {
+        return exts.hasNotNull(ENV_KEY) && !exts.has(IGNORE);
+    }
+    public static DebugContext get(Extensions exts) {
+        if (enabled(exts)) return exts.get(ENV_KEY);
+        else return new DebugContext(false);
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/debug/DebugController.java

@@ -0,0 +1,62 @@
+package me.topchetoeu.jscript.core.engine.debug;
+
+import java.util.TreeSet;
+
+import me.topchetoeu.jscript.common.Filename;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.utils.mapping.SourceMap;
+
+public interface DebugController {
+    /**
+     * Called when a script has been loaded
+     * @param filename The name of the source
+     * @param source The name of the source
+     * @param breakpoints A set of all the breakpointable locations in this source
+     * @param map The source map associated with this file. null if this source map isn't mapped
+     */
+    void onSource(Filename filename, String source, TreeSet<Location> breakpoints, SourceMap map);
+
+    /**
+     * 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, Values.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 before a frame has been pushed on 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 pushed
+     */
+    void onFramePush(Context ctx, CodeFrame frame);
+    /**
+     * 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);
+
+    public static DebugController empty() {
+        return new DebugController () {
+            @Override public void onFramePop(Context ctx, CodeFrame frame) { }
+            @Override public void onFramePush(Context ctx, CodeFrame frame) { }
+            @Override public boolean onInstruction(Context ctx, CodeFrame frame, Instruction instruction, Object returnVal, EngineException error, boolean caught) {
+                return false;
+            }
+            @Override public void onSource(Filename filename, String source, TreeSet<Location> breakpoints, SourceMap map) { }
+        };
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/frame/CodeFrame.java

@@ -0,0 +1,332 @@
+package me.topchetoeu.jscript.core.engine.frame;
+
+import java.util.List;
+import java.util.Stack;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.debug.DebugContext;
+import me.topchetoeu.jscript.core.engine.scope.LocalScope;
+import me.topchetoeu.jscript.core.engine.scope.ValueVariable;
+import me.topchetoeu.jscript.core.engine.values.ArrayValue;
+import me.topchetoeu.jscript.core.engine.values.CodeFunction;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.ScopeValue;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.core.exceptions.InterruptException;
+
+public class CodeFrame {
+    public static enum TryState {
+        TRY,
+        CATCH,
+        FINALLY,
+    }
+
+    public static class TryCtx {
+        public final int start, end, catchStart, finallyStart;
+        public final int restoreStackPtr;
+        public final TryState state;
+        public final EngineException error;
+        public final PendingResult result;
+
+        public boolean hasCatch() { return catchStart >= 0; }
+        public boolean hasFinally() { return finallyStart >= 0; }
+
+        public boolean inBounds(int ptr) {
+            return ptr >= start && ptr < end;
+        }
+
+        public void setCause(EngineException target) {
+            if (error != null) target.setCause(error);
+        }
+        public TryCtx _catch(EngineException e) {
+            return new TryCtx(TryState.CATCH, e, result, restoreStackPtr, start, end, -1, finallyStart);
+        }
+        public TryCtx _finally(PendingResult res) {
+            return new TryCtx(TryState.FINALLY, error, res, restoreStackPtr, start, end, -1, -1);
+        }
+
+        public TryCtx(TryState state, EngineException err, PendingResult res, int stackPtr, int start, int end, int catchStart, int finallyStart) {
+            this.catchStart = catchStart;
+            this.finallyStart = finallyStart;
+            this.restoreStackPtr = stackPtr;
+            this.result = res == null ? PendingResult.ofNone() : res;
+            this.state = state;
+            this.start = start;
+            this.end = end;
+            this.error = err;
+        }
+    }
+
+    private static class PendingResult {
+        public final boolean isReturn, isJump, isThrow;
+        public final Object value;
+        public final EngineException error;
+        public final int ptr;
+        public final Instruction instruction;
+
+        private PendingResult(Instruction instr, boolean isReturn, boolean isJump, boolean isThrow, Object value, EngineException error, int ptr) {
+            this.instruction = instr;
+            this.isReturn = isReturn;
+            this.isJump = isJump;
+            this.isThrow = isThrow;
+            this.value = value;
+            this.error = error;
+            this.ptr = ptr;
+        }
+
+        public static PendingResult ofNone() {
+            return new PendingResult(null, false, false, false, null, null, 0);
+        }
+        public static PendingResult ofReturn(Object value, Instruction instr) {
+            return new PendingResult(instr, true, false, false, value, null, 0);
+        }
+        public static PendingResult ofThrow(EngineException error, Instruction instr) {
+            return new PendingResult(instr, false, false, true, null, error, 0);
+        }
+        public static PendingResult ofJump(int codePtr, Instruction instr) {
+            return new PendingResult(instr, false, true, false, null, null, codePtr);
+        }
+    }
+
+    public final LocalScope scope;
+    public final Object thisArg;
+    public final Object[] args;
+    public final Stack<TryCtx> tryStack = new Stack<>();
+    public final CodeFunction function;
+    public final Context ctx;
+    public Object[] stack = new Object[32];
+    public int stackPtr = 0;
+    public int codePtr = 0;
+    public boolean jumpFlag = false, popTryFlag = false;
+    private Location prevLoc = null;
+
+    public ObjectValue getLocalScope(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(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() {
+        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 start, int end, int catchStart, int finallyStart) {
+        var err = tryStack.empty() ? null : tryStack.peek().error;
+        var res = new TryCtx(TryState.TRY, err, null, stackPtr, start, end, catchStart, finallyStart);
+
+        tryStack.add(res);
+    }
+
+    public Object peek() {
+        return peek(0);
+    }
+    public Object peek(int offset) {
+        if (stackPtr <= offset) return null;
+        else return stack[stackPtr - 1 - offset];
+    }
+    public Object pop() {
+        if (stackPtr == 0) return null;
+        return stack[--stackPtr];
+    }
+    public Object[] take(int n) {
+        int srcI = stackPtr - n;
+        if (srcI < 0) srcI = 0;
+
+        int dstI = n + srcI - stackPtr;
+        int copyN = stackPtr - srcI;
+
+        Object[] res = new Object[n];
+        System.arraycopy(stack, srcI, res, dstI, copyN);
+        stackPtr -= copyN;
+
+        return res;
+    }
+    public void push(Object val) {
+        if (stack.length <= stackPtr) {
+            var newStack = new Object[stack.length * 2];
+            System.arraycopy(stack, 0, newStack, 0, stack.length);
+            stack = newStack;
+        }
+        stack[stackPtr++] = Values.normalize(ctx, val);
+    }
+
+    public Object next(Object value, Object returnValue, EngineException error) {
+        if (value != Values.NO_RETURN) push(value);
+
+        Instruction instr = null;
+        if (codePtr >= 0 && codePtr < function.body.length) instr = function.body[codePtr];
+
+        if (returnValue == Values.NO_RETURN && error == null) {
+            try {
+                if (Thread.currentThread().isInterrupted()) throw new InterruptException();
+
+                if (instr == null) returnValue = null;
+                else {
+                    DebugContext.get(ctx).onInstruction(ctx, this, instr, Values.NO_RETURN, null, false);
+
+                    if (instr.location != null) prevLoc = instr.location;
+
+                    try {
+                        this.jumpFlag = this.popTryFlag = false;
+                        returnValue = Runners.exec(ctx, instr, this);
+                    }
+                    catch (EngineException e) {
+                        error = e.add(ctx, function.name, prevLoc);
+                    }
+                }
+            }
+            catch (EngineException e) { error = e; }
+        }
+
+        while (!tryStack.empty()) {
+            var tryCtx = tryStack.peek();
+            TryCtx newCtx = null;
+
+            if (error != null) {
+                tryCtx.setCause(error);
+                if (tryCtx.hasCatch()) newCtx = tryCtx._catch(error);
+                else if (tryCtx.hasFinally()) newCtx = tryCtx._finally(PendingResult.ofThrow(error, instr));
+            }
+            else if (returnValue != Values.NO_RETURN) {
+                if (tryCtx.hasFinally()) newCtx = tryCtx._finally(PendingResult.ofReturn(returnValue, instr));
+            }
+            else if (jumpFlag && !tryCtx.inBounds(codePtr)) {
+                if (tryCtx.hasFinally()) newCtx = tryCtx._finally(PendingResult.ofJump(codePtr, instr));
+            }
+            else if (!this.popTryFlag) newCtx = tryCtx;
+
+            if (newCtx != null) {
+                if (newCtx != tryCtx) {
+                    switch (newCtx.state) {
+                        case CATCH:
+                            if (tryCtx.state != TryState.CATCH) scope.catchVars.add(new ValueVariable(false, error.value));
+                            codePtr = tryCtx.catchStart;
+                            stackPtr = tryCtx.restoreStackPtr;
+                            break;
+                        case FINALLY:
+                            if (tryCtx.state == TryState.CATCH) scope.catchVars.remove(scope.catchVars.size() - 1);
+                            codePtr = tryCtx.finallyStart;
+                            stackPtr = tryCtx.restoreStackPtr;
+                        default:
+                    }
+
+                    tryStack.pop();
+                    tryStack.push(newCtx);
+                }
+                error = null;
+                returnValue = Values.NO_RETURN;
+                break;
+            }
+            else {
+                popTryFlag = false;
+                if (tryCtx.state == TryState.CATCH) scope.catchVars.remove(scope.catchVars.size() - 1);
+
+                if (tryCtx.state != TryState.FINALLY && tryCtx.hasFinally()) {
+                    codePtr = tryCtx.finallyStart;
+                    stackPtr = tryCtx.restoreStackPtr;
+                    tryStack.pop();
+                    tryStack.push(tryCtx._finally(null));
+                    break;
+                }
+                else {
+                    tryStack.pop();
+                    codePtr = tryCtx.end;
+                    if (tryCtx.result.instruction != null) instr = tryCtx.result.instruction;
+                    if (!jumpFlag && returnValue == Values.NO_RETURN && error == null) {
+                        if (tryCtx.result.isJump) {
+                            codePtr = tryCtx.result.ptr;
+                            jumpFlag = true;
+                        }
+                        if (tryCtx.result.isReturn) returnValue = tryCtx.result.value;
+                        if (error == null && tryCtx.result.isThrow) {
+                            error = tryCtx.result.error;
+                        }
+                    }
+                    if (error != null) tryCtx.setCause(error);
+                    continue;
+                }
+            }
+        }
+
+        if (error != null) {
+            var caught = false;
+
+            for (var frame : ctx.frames()) {
+                for (var tryCtx : frame.tryStack) {
+                    if (tryCtx.state == TryState.TRY) caught = true;
+                }
+            }
+
+            DebugContext.get(ctx).onInstruction(ctx, this, instr, null, error, caught);
+            throw error;
+        }
+        if (returnValue != Values.NO_RETURN) {
+            DebugContext.get(ctx).onInstruction(ctx, this, instr, returnValue, null, false);
+            return returnValue;
+        }
+
+        return Values.NO_RETURN;
+    }
+
+    public void onPush() {
+        DebugContext.get(ctx).onFramePush(ctx, this);
+    }
+    public void onPop() {
+        DebugContext.get(ctx.parent).onFramePop(ctx.parent, this);
+    }
+
+    public CodeFrame(Context ctx, Object thisArg, Object[] args, CodeFunction func) {
+        this.args = args.clone();
+        this.scope = new LocalScope(func.localsN, func.captures);
+        this.scope.get(0).set(null, thisArg);
+        var argsObj = new ArrayValue();
+        for (var i = 0; i < args.length; i++) {
+            argsObj.set(ctx, i, args[i]);
+        }
+        this.scope.get(1).value = argsObj;
+
+        this.thisArg = thisArg;
+        this.function = func;
+        this.ctx = ctx.pushFrame(this);
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/frame/ConvertHint.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.engine.frame;
+package me.topchetoeu.jscript.core.engine.frame;
 
 public enum ConvertHint {
     TOSTRING,

src/java/me/topchetoeu/jscript/core/engine/frame/Runners.java

@@ -1,21 +1,22 @@
-package me.topchetoeu.jscript.engine.frame;
+package me.topchetoeu.jscript.core.engine.frame;
 
 import java.util.Collections;
 
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.Operation;
-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.Symbol;
-import me.topchetoeu.jscript.engine.values.Values;
-import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Engine;
+import me.topchetoeu.jscript.core.engine.Environment;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.scope.ValueVariable;
+import me.topchetoeu.jscript.core.engine.values.ArrayValue;
+import me.topchetoeu.jscript.core.engine.values.CodeFunction;
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.Symbol;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
 
 public class Runners {
-    public static final Object NO_RETURN = new Object();
-
     public static Object execReturn(Context ctx, Instruction instr, CodeFrame frame) {
         return frame.pop();
     }
@@ -26,46 +27,31 @@ public class Runners {
         throw EngineException.ofSyntax((String)instr.get(0));
     }
 
-    private static Object call(Context ctx, Object func, Object thisArg, Object ...args) {
-        return Values.call(ctx, func, thisArg, args);
-    }
-
     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(Values.call(ctx, func, thisArg, callArgs));
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     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.push(Values.callNew(ctx, funcObj, callArgs));
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object execMakeVar(Context ctx, Instruction instr, CodeFrame frame) {
         var name = (String)instr.get(0);
-        ctx.environment().global.define(name);
+        ctx.environment.global.define(name);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execDefProp(Context ctx, Instruction instr, CodeFrame frame) {
         var setter = frame.pop();
@@ -73,14 +59,14 @@ public class Runners {
         var name = frame.pop();
         var obj = frame.pop();
 
-        if (getter != null && !Values.isFunction(getter)) throw EngineException.ofType("Getter must be a function or undefined.");
-        if (setter != null && !Values.isFunction(setter)) throw EngineException.ofType("Setter must be a function or undefined.");
-        if (!Values.isObject(obj)) throw EngineException.ofType("Property apply target must be an object.");
+        if (getter != null && !(getter instanceof FunctionValue)) throw EngineException.ofType("Getter must be a function or undefined.");
+        if (setter != null && !(setter instanceof FunctionValue)) throw EngineException.ofType("Setter must be a function or undefined.");
+        if (!(obj instanceof ObjectValue)) throw EngineException.ofType("Property apply target must be an object.");
         Values.object(obj).defineProperty(ctx, name, Values.function(getter), Values.function(setter), false, false);
 
-        frame.push(ctx, obj);
+        frame.push(obj);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execInstanceof(Context ctx, Instruction instr, CodeFrame frame) {
         var type = frame.pop();
@@ -88,144 +74,143 @@ public class Runners {
 
         if (!Values.isPrimitive(type)) {
             var proto = Values.getMember(ctx, type, "prototype");
-            frame.push(ctx, Values.isInstanceOf(ctx, obj, proto));
+            frame.push(Values.isInstanceOf(ctx, obj, proto));
         }
         else {
-            frame.push(ctx, false);
+            frame.push(false);
         }
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     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(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(obj);
         }
 
-        arr.defineProperty(ctx, "length", i);
-
-        frame.push(ctx, arr);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
-    public static Object execTry(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.addTry(instr.get(0), instr.get(1), instr.get(2));
+    public static Object execTryStart(Context ctx, Instruction instr, CodeFrame frame) {
+        int start = frame.codePtr + 1;
+        int catchStart = (int)instr.get(0);
+        int finallyStart = (int)instr.get(1);
+        if (finallyStart >= 0) finallyStart += start;
+        if (catchStart >= 0) catchStart += start;
+        int end = (int)instr.get(2) + start;
+        frame.addTry(start, end, catchStart, finallyStart);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
+    }
+    public static Object execTryEnd(Context ctx, Instruction instr, CodeFrame frame) {
+        frame.popTryFlag = true;
+        return Values.NO_RETURN;
     }
 
     public static Object execDup(Context ctx, Instruction instr, CodeFrame frame) {
-        int offset = instr.get(0), count = instr.get(1);
+        int count = instr.get(0);
 
         for (var i = 0; i < count; i++) {
-            frame.push(ctx, frame.peek(offset + count - 1));
+            frame.push(frame.peek(count - 1));
         }
 
         frame.codePtr++;
-        return NO_RETURN;
-    }
-    public static Object execMove(Context ctx, Instruction instr, CodeFrame frame) {
-        int offset = instr.get(0), count = instr.get(1);
-
-        var tmp = frame.take(offset);
-        var res = frame.take(count);
-
-        for (var i = 0; i < offset; i++) frame.push(ctx, tmp[i]);
-        for (var i = 0; i < count; i++) frame.push(ctx, res[i]);
-
-        frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadUndefined(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, null);
+        frame.push(null);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadValue(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, instr.get(0));
+        frame.push(instr.get(0));
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadVar(Context ctx, Instruction instr, CodeFrame frame) {
         var i = instr.get(0);
 
-        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));
+        if (i instanceof String) frame.push(ctx.environment.global.get(ctx, (String)i));
+        else frame.push(frame.scope.get((int)i).get(ctx));
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadObj(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, new ObjectValue());
+        frame.push(new ObjectValue());
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadGlob(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, ctx.environment().global.obj);
+        frame.push(ctx.environment.global.obj);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadArr(Context ctx, Instruction instr, CodeFrame frame) {
         var res = new ArrayValue();
         res.setSize(instr.get(0));
-        frame.push(ctx, res);
+        frame.push(res);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadFunc(Context ctx, Instruction instr, CodeFrame frame) {
         long id = (Long)instr.get(0);
-        int localsN = (Integer)instr.get(1);
-        int len = (Integer)instr.get(2);
-        var captures = new ValueVariable[instr.params.length - 3];
+        var captures = new ValueVariable[instr.params.length - 1];
 
-        for (var i = 3; i < instr.params.length; i++) {
-            captures[i - 3] = frame.scope.get(instr.get(i));
+        for (var i = 1; i < instr.params.length; i++) {
+            captures[i - 1] = frame.scope.get(instr.get(i));
         }
 
-        var body = ctx.engine.functions.get(id);
-        var func = new CodeFunction(ctx.environment(), "", localsN, len, captures, body);
+        var func = new CodeFunction(ctx.environment, "", Engine.functions.get(id), captures);
 
-        frame.push(ctx, func);
+        frame.push(func);
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadMember(Context ctx, Instruction instr, CodeFrame frame) {
         var key = frame.pop();
         var obj = frame.pop();
 
         try {
-            frame.push(ctx, Values.getMember(ctx, obj, key));
+            frame.push(Values.getMember(ctx, obj, key));
         }
         catch (IllegalArgumentException e) {
             throw EngineException.ofType(e.getMessage());
         }
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execLoadKeyMember(Context ctx, Instruction instr, CodeFrame frame) {
-        frame.push(ctx, instr.get(0));
+        frame.push(instr.get(0));
         return execLoadMember(ctx, instr, frame);
     }
     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)));
+        if (ctx.hasNotNull(Environment.REGEX_CONSTR)) {
+            frame.push(Values.callNew(ctx, ctx.get(Environment.REGEX_CONSTR), instr.get(0), instr.get(1)));
+        }
+        else {
+            throw EngineException.ofSyntax("Regex is not supported.");
+        }
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object execDiscard(Context ctx, Instruction instr, CodeFrame frame) {
         frame.pop();
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execStoreMember(Context ctx, Instruction instr, CodeFrame frame) {
         var val = frame.pop();
@@ -233,30 +218,30 @@ public class Runners {
         var obj = frame.pop();
 
         if (!Values.setMember(ctx, obj, key, val)) throw EngineException.ofSyntax("Can't set member '" + key + "'.");
-        if ((boolean)instr.get(0)) frame.push(ctx, val);
+        if ((boolean)instr.get(0)) frame.push(val);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     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.environment().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++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execStoreSelfFunc(Context ctx, Instruction instr, CodeFrame frame) {
         frame.scope.locals[(int)instr.get(0)].set(ctx, frame.function);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     
     public static Object execJmp(Context ctx, Instruction instr, CodeFrame frame) {
         frame.codePtr += (int)instr.get(0);
         frame.jumpFlag = true;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execJmpIf(Context ctx, Instruction instr, CodeFrame frame) {
         if (Values.toBoolean(frame.pop())) {
@@ -264,7 +249,7 @@ public class Runners {
             frame.jumpFlag = true;
         }
         else frame.codePtr ++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execJmpIfNot(Context ctx, Instruction instr, CodeFrame frame) {
         if (Values.not(frame.pop())) {
@@ -272,37 +257,37 @@ public class Runners {
             frame.jumpFlag = true;
         }
         else frame.codePtr ++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object execIn(Context ctx, Instruction instr, CodeFrame frame) {
         var obj = frame.pop();
         var index = frame.pop();
 
-        frame.push(ctx, Values.hasMember(ctx, obj, index, false));
+        frame.push(Values.hasMember(ctx, obj, index, false));
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execTypeof(Context ctx, Instruction instr, CodeFrame frame) {
         String name = instr.get(0);
         Object obj;
 
         if (name != null) {
-            if (ctx.environment().global.has(ctx, name)) {
-                obj = ctx.environment().global.get(ctx, name);
+            if (ctx.environment.global.has(ctx, name)) {
+                obj = ctx.environment.global.get(ctx, name);
             }
             else obj = null;
         }
         else obj = frame.pop();
 
-        frame.push(ctx, Values.type(obj));
+        frame.push(Values.type(obj));
 
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
     public static Object execNop(Context ctx, Instruction instr, CodeFrame frame) {
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object execDelete(Context ctx, Instruction instr, CodeFrame frame) {
@@ -310,9 +295,8 @@ public class Runners {
         var val = frame.pop();
 
         if (!Values.deleteMember(ctx, val, key)) throw EngineException.ofSyntax("Can't delete member '" + key + "'.");
-        frame.push(ctx, true);
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object execOperation(Context ctx, Instruction instr, CodeFrame frame) {
@@ -321,9 +305,9 @@ public class Runners {
 
         for (var i = op.operands - 1; i >= 0; i--) args[i] = frame.pop();
 
-        frame.push(ctx, Values.operation(ctx, op, args));
+        frame.push(Values.operation(ctx, op, args));
         frame.codePtr++;
-        return NO_RETURN;
+        return Values.NO_RETURN;
     }
 
     public static Object exec(Context ctx, Instruction instr, CodeFrame frame) {
@@ -334,10 +318,10 @@ public class Runners {
             case THROW_SYNTAX: return execThrowSyntax(ctx, instr, frame);
             case CALL: return execCall(ctx, instr, frame);
             case CALL_NEW: return execCallNew(ctx, instr, frame);
-            case TRY: return execTry(ctx, instr, frame);
+            case TRY_START: return execTryStart(ctx, instr, frame);
+            case TRY_END: return execTryEnd(ctx, instr, frame);
 
             case DUP: return execDup(ctx, instr, frame);
-            case MOVE: return execMove(ctx, instr, frame);
             case LOAD_VALUE: return execLoadValue(ctx, instr, frame);
             case LOAD_VAR: return execLoadVar(ctx, instr, frame);
             case LOAD_OBJ: return execLoadObj(ctx, instr, frame);

src/java/me/topchetoeu/jscript/core/engine/scope/GlobalScope.java

@@ -1,22 +1,20 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
 import java.util.HashSet;
 import java.util.Set;
 
-import me.topchetoeu.jscript.engine.Context;
-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.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.values.FunctionValue;
+import me.topchetoeu.jscript.core.engine.values.NativeFunction;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
 
 public class GlobalScope implements ScopeRecord {
     public final ObjectValue obj;
 
-    @Override
-    public GlobalScope parent() { return null; }
-
     public boolean has(Context ctx, String name) {
-        return obj.hasMember(ctx, name, false);
+        return Values.hasMember(null, obj, name, false);
     }
     public Object getKey(String name) {
         return name;
@@ -24,22 +22,22 @@ public class GlobalScope implements ScopeRecord {
 
     public GlobalScope globalChild() {
         var obj = new ObjectValue();
-        obj.setPrototype(null, this.obj);
+        Values.setPrototype(null, obj, this.obj);
         return new GlobalScope(obj);
     }
     public LocalScopeRecord child() {
-        return new LocalScopeRecord(this);
+        return new LocalScopeRecord();
     }
 
     public Object define(String name) {
-        if (obj.hasMember(null, name, true)) return name;
-        obj.defineProperty(null, name, null);
+        if (Values.hasMember(Context.NULL, obj, name, false)) return name;
+        obj.defineProperty(Context.NULL, name, null);
         return name;
     }
     public void define(String name, Variable val) {
-        obj.defineProperty(null, name,
-            new NativeFunction("get " + name, (ctx, th, a) -> val.get(ctx)),
-            new NativeFunction("set " + name, (ctx, th, args) -> { val.set(ctx, args.length > 0 ? args[0] : null); return null; }),
+        obj.defineProperty(Context.NULL, name,
+            new NativeFunction("get " + name, args -> val.get(args.ctx)),
+            new NativeFunction("set " + name, args -> { val.set(args.ctx, args.get(0)); return null; }),
             true, true
         );
     }
@@ -54,12 +52,12 @@ public class GlobalScope implements ScopeRecord {
     }
 
     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);
+        if (!Values.hasMember(ctx, obj, name, false)) throw EngineException.ofSyntax("The variable '" + name + "' doesn't exist.");
+        else return Values.getMember(ctx, obj, name);
     }
     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.");
+        if (!Values.hasMember(ctx, obj, name, false)) throw EngineException.ofSyntax("The variable '" + name + "' doesn't exist.");
+        if (!Values.setMember(ctx, obj, name, val)) throw EngineException.ofSyntax("The global '" + name + "' is readonly.");
     }
 
     public Set<String> keys() {

src/java/me/topchetoeu/jscript/core/engine/scope/LocalScope.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
 import java.util.ArrayList;
 
@@ -8,8 +8,7 @@ public class LocalScope {
     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];
     }

src/java/me/topchetoeu/jscript/core/engine/scope/LocalScopeRecord.java

@@ -1,12 +1,9 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
 import java.util.ArrayList;
 
-import me.topchetoeu.jscript.engine.Context;
-
 public class LocalScopeRecord implements ScopeRecord {
     public final LocalScopeRecord parent;
-    public final GlobalScope global;
 
     private final ArrayList<String> captures = new ArrayList<>();
     private final ArrayList<String> locals = new ArrayList<>();
@@ -18,11 +15,8 @@ public class LocalScopeRecord implements ScopeRecord {
         return locals.toArray(String[]::new);
     }
 
-    @Override
-    public LocalScopeRecord parent() { return parent; }
-
     public LocalScopeRecord child() {
-        return new LocalScopeRecord(this, global);
+        return new LocalScopeRecord(this);
     }
 
     public int localsCount() {
@@ -62,12 +56,6 @@ public class LocalScopeRecord implements ScopeRecord {
 
         return name;
     }
-    public boolean has(Context ctx, String name) {
-        return
-            global.has(ctx, name) ||
-            locals.contains(name) ||
-            parent != null && parent.has(ctx, name);
-    }
     public Object define(String name, boolean force) {
         if (!force && locals.contains(name)) return locals.indexOf(name);
         locals.add(name);
@@ -80,12 +68,10 @@ public class LocalScopeRecord implements ScopeRecord {
         locals.remove(locals.size() - 1);
     }
 
-    public LocalScopeRecord(GlobalScope global) {
+    public LocalScopeRecord() {
         this.parent = null;
-        this.global = global;
     }
-    public LocalScopeRecord(LocalScopeRecord parent, GlobalScope global) {
+    public LocalScopeRecord(LocalScopeRecord parent) {
         this.parent = parent;
-        this.global = global;
     }
 }

src/java/me/topchetoeu/jscript/core/engine/scope/ScopeRecord.java

@@ -1,8 +1,7 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
 public interface ScopeRecord {
     public Object getKey(String name);
     public Object define(String name);
-    public ScopeRecord parent();
     public LocalScopeRecord child();
 }

src/java/me/topchetoeu/jscript/core/engine/scope/ValueVariable.java

@@ -1,7 +1,7 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.values.Values;
 
 public class ValueVariable implements Variable {
     public boolean readonly;

src/java/me/topchetoeu/jscript/core/engine/scope/Variable.java

@@ -1,6 +1,6 @@
-package me.topchetoeu.jscript.engine.scope;
+package me.topchetoeu.jscript.core.engine.scope;
 
-import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.core.engine.Context;
 
 public interface Variable {
     Object get(Context ctx);

src/java/me/topchetoeu/jscript/core/engine/values/ArrayValue.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -6,7 +6,7 @@ import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 
-import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.core.engine.Context;
 
 // TODO: Make methods generic
 public class ArrayValue extends ObjectValue implements Iterable<Object> {
@@ -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;
@@ -83,9 +84,12 @@ 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
+        if (destStart + count > arr.size) arr.size = destStart + count;
+
         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 +101,7 @@ 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);
 

src/java/me/topchetoeu/jscript/core/engine/values/CodeFunction.java

@@ -1,18 +1,15 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.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.StackData;
-import me.topchetoeu.jscript.engine.frame.CodeFrame;
-import me.topchetoeu.jscript.engine.frame.Runners;
-import me.topchetoeu.jscript.engine.scope.ValueVariable;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.compilation.FunctionBody;
+import me.topchetoeu.jscript.core.compilation.Instruction;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Environment;
+import me.topchetoeu.jscript.core.engine.frame.CodeFrame;
+import me.topchetoeu.jscript.core.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;
@@ -34,27 +31,27 @@ public class CodeFunction extends FunctionValue {
     @Override
     public Object call(Context ctx, Object thisArg, Object ...args) {
         var frame = new CodeFrame(ctx, thisArg, args, this);
-        try {
-            StackData.pushFrame(ctx, frame);
 
+        frame.onPush();
+
+        try {
             while (true) {
-                var res = frame.next(ctx, Runners.NO_RETURN, Runners.NO_RETURN, null);
-                if (res != Runners.NO_RETURN) return res;
+                var res = frame.next(Values.NO_RETURN, Values.NO_RETURN, null);
+                if (res != Values.NO_RETURN) return res;
             }
         }
         finally {
-            StackData.popFrame(ctx, frame);
+            frame.onPop();
         }
     }
 
-    public CodeFunction(Environment environment, String name, int localsN, int length, ValueVariable[] captures, FunctionBody body) {
-        super(name, length);
+    public CodeFunction(Environment environment, String name, FunctionBody body, ValueVariable... captures) {
+        super(name, body.argsN);
         this.captures = captures;
         this.captureNames = body.captureNames;
         this.localNames = body.localNames;
         this.environment = environment;
-        this.localsN = localsN;
-        this.length = length;
+        this.localsN = body.localsN;
         this.body = body.instructions;
     }
 }

src/java/me/topchetoeu/jscript/core/engine/values/FunctionValue.java

@@ -1,8 +1,8 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
 import java.util.List;
 
-import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.core.engine.Context;
 
 public abstract class FunctionValue extends ObjectValue {
     public String name = "";
@@ -11,7 +11,7 @@ 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);
@@ -21,21 +21,21 @@ public abstract class FunctionValue extends ObjectValue {
 
     @Override
     protected Object getField(Context ctx, Object key) {
-        if (key.equals("name")) return name;
-        if (key.equals("length")) return length;
+        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) {
-        if (key.equals("name")) name = Values.toString(ctx, val);
-        else if (key.equals("length")) length = (int)Values.toNumber(ctx, 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) {
-        if (key.equals("name")) return true;
-        if (key.equals("length")) return true;
+        if ("name".equals(key)) return true;
+        if ("length".equals(key)) return true;
         return super.hasField(ctx, key);
     }
 

src/java/me/topchetoeu/jscript/core/engine/values/NativeFunction.java

@@ -1,17 +1,18 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
-import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.utils.interop.Arguments;
 
 public class NativeFunction extends FunctionValue {
     public static interface NativeFunctionRunner {
-        Object run(Context ctx, Object thisArg, Object[] args);
+        Object run(Arguments args);
     }
 
     public final NativeFunctionRunner action;
 
     @Override
     public Object call(Context ctx, Object thisArg, Object ...args) {
-        return action.run(ctx, thisArg, args);
+        return action.run(new Arguments(ctx, thisArg, args));
     }
 
     public NativeFunction(String name, NativeFunctionRunner action) {

src/java/me/topchetoeu/jscript/core/engine/values/NativeWrapper.java

@@ -0,0 +1,32 @@
+package me.topchetoeu.jscript.core.engine.values;
+
+import me.topchetoeu.jscript.core.engine.Context;
+
+public class NativeWrapper extends ObjectValue {
+    private static final Object NATIVE_PROTO = new Object();
+    public final Object wrapped;
+
+    @Override
+    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;
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/values/ObjectValue.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
@@ -6,7 +6,8 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 
-import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Environment;
 
 public class ObjectValue {
     public static enum PlaceholderProto {
@@ -53,6 +54,13 @@ public class ObjectValue {
     public LinkedHashSet<Object> nonConfigurableSet = new LinkedHashSet<>();
     public LinkedHashSet<Object> nonEnumerableSet = new LinkedHashSet<>();
 
+    private 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;
+    }
+
     public final boolean memberWritable(Object key) {
         if (state == State.FROZEN) return false;
         return !values.containsKey(key) || !nonWritableSet.contains(key);
@@ -103,8 +111,7 @@ 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);
@@ -147,45 +154,18 @@ public class ObjectValue {
 
     public ObjectValue getPrototype(Context ctx) {
         try {
-            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");
+            if (prototype == OBJ_PROTO) return ctx.get(Environment.OBJECT_PROTO);
+            if (prototype == ARR_PROTO) return ctx.get(Environment.ARRAY_PROTO);
+            if (prototype == FUNC_PROTO) return ctx.get(Environment.FUNCTION_PROTO);
+            if (prototype == ERR_PROTO) return ctx.get(Environment.ERROR_PROTO);
+            if (prototype == RANGE_ERR_PROTO) return ctx.get(Environment.RANGE_ERR_PROTO);
+            if (prototype == SYNTAX_ERR_PROTO) return ctx.get(Environment.SYNTAX_ERR_PROTO);
+            if (prototype == TYPE_ERR_PROTO) return ctx.get(Environment.TYPE_ERR_PROTO);
         }
         catch (NullPointerException e) { return null; }
 
         return (ObjectValue)prototype;
     }
-    public final boolean setPrototype(Context ctx, Object val) {
-        val = Values.normalize(ctx, val);
-
-        if (!extensible()) return false;
-        if (val == null || val == Values.NULL) {
-            prototype = null;
-            return true;
-        }
-        else if (Values.isObject(val)) {
-            var obj = Values.object(val);
-
-            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;
-
-            return true;
-        }
-        return false;
-    }
     public final boolean setPrototype(PlaceholderProto val) {
         if (!extensible()) return false;
         switch (val) {
@@ -201,18 +181,21 @@ public class ObjectValue {
         return true;
     }
 
-    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;
-    }
+    /**
+     * A method, used to get the value of a field. If a property is bound to
+     * this key, but not a field, this method should return null.
+     */
     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;
     }
+    /**
+     * Changes the value of a field, that is bound to the given key. If no field is
+     * bound to this key, a new field should be created with the given value
+     * @return Whether or not the operation was successful
+     */
     protected boolean setField(Context ctx, Object key, Object val) {
         if (val instanceof FunctionValue && ((FunctionValue)val).name.equals("")) {
             ((FunctionValue)val).name = Values.toString(ctx, key);
@@ -221,9 +204,16 @@ public class ObjectValue {
         values.put(key, val);
         return true;
     }
+    /**
+     * Deletes the field bound to the given key.
+     */
     protected void deleteField(Context ctx, Object key) {
         values.remove(key);
     }
+    /**
+     * Returns whether or not there is a field bound to the given key.
+     * This must ignore properties
+     */
     protected boolean hasField(Context ctx, Object key) {
         return values.containsKey(key);
     }
@@ -244,10 +234,6 @@ public class ObjectValue {
         }
         else return getField(ctx, key);
     }
-    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) {
         key = Values.normalize(ctx, key); val = Values.normalize(ctx, val);
 
@@ -263,18 +249,14 @@ 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) {
-        return setMember(ctx, Values.normalize(ctx, key), Values.normalize(ctx, val), this, onlyProps);
-    }
-
     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;
@@ -291,6 +273,33 @@ public class ObjectValue {
         deleteField(ctx, key);
         return true;
     }
+    public final boolean setPrototype(Context ctx, Object val) {
+        val = Values.normalize(ctx, val);
+
+        if (!extensible()) return false;
+        if (val == null || val == Values.NULL) {
+            prototype = null;
+            return true;
+        }
+        else if (val instanceof ObjectValue) {
+            var obj = Values.object(val);
+
+            if (ctx != null) {
+                if (obj == ctx.get(Environment.OBJECT_PROTO)) prototype = OBJ_PROTO;
+                else if (obj == ctx.get(Environment.ARRAY_PROTO)) prototype = ARR_PROTO;
+                else if (obj == ctx.get(Environment.FUNCTION_PROTO)) prototype = FUNC_PROTO;
+                else if (obj == ctx.get(Environment.ERROR_PROTO)) prototype = ERR_PROTO;
+                else if (obj == ctx.get(Environment.SYNTAX_ERR_PROTO)) prototype = SYNTAX_ERR_PROTO;
+                else if (obj == ctx.get(Environment.TYPE_ERR_PROTO)) prototype = TYPE_ERR_PROTO;
+                else if (obj == ctx.get(Environment.RANGE_ERR_PROTO)) prototype = RANGE_ERR_PROTO;
+                else prototype = obj;
+            }
+            else prototype = obj;
+
+            return true;
+        }
+        return false;
+    }
 
     public final ObjectValue getMemberDescriptor(Context ctx, Object key) {
         key = Values.normalize(ctx, key);

src/java/me/topchetoeu/jscript/core/engine/values/ScopeValue.java

@@ -1,10 +1,10 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
 import java.util.HashMap;
 import java.util.List;
 
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.scope.ValueVariable;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.scope.ValueVariable;
 
 public class ScopeValue extends ObjectValue {
     public final ValueVariable[] variables;
@@ -22,6 +22,9 @@ public class ScopeValue extends ObjectValue {
             return true;
         }
 
+        var proto = getPrototype(ctx);
+        if (proto != null && proto.hasMember(ctx, key, false) && proto.setField(ctx, key, val)) return true;
+
         return super.setField(ctx, key, val);
     }
     @Override

src/java/me/topchetoeu/jscript/core/engine/values/Symbol.java

@@ -0,0 +1,28 @@
+package me.topchetoeu.jscript.core.engine.values;
+
+import java.util.HashMap;
+
+public final class Symbol {
+    private static final HashMap<String, Symbol> registry = new HashMap<>();
+
+    public final String value;
+
+    public Symbol(String value) {
+        this.value = value;
+    }
+
+    @Override
+    public String toString() {
+        if (value == null) return "Symbol";
+        else return "@@" + value;
+    }
+
+    public static Symbol get(String name) {
+        if (registry.containsKey(name)) return registry.get(name);
+        else {
+            var res = new Symbol(name);
+            registry.put(name, res);
+            return res;
+        }
+    }
+}

src/java/me/topchetoeu/jscript/core/engine/values/Values.java

@@ -1,5 +1,7 @@
-package me.topchetoeu.jscript.engine.values;
+package me.topchetoeu.jscript.core.engine.values;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
 import java.lang.reflect.Array;
 import java.math.BigDecimal;
 import java.util.ArrayList;
@@ -10,20 +12,37 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.Operation;
-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.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Environment;
+import me.topchetoeu.jscript.core.engine.Operation;
+import me.topchetoeu.jscript.core.engine.frame.ConvertHint;
+import me.topchetoeu.jscript.core.exceptions.ConvertException;
+import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.core.exceptions.SyntaxException;
+import me.topchetoeu.jscript.lib.PromiseLib;
 
 public class Values {
-    public static final Object NULL = new Object();
+    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 final Object NO_RETURN = new Object();
 
-    public static boolean isObject(Object val) { return val instanceof ObjectValue; }
-    public static boolean isFunction(Object val) { return val instanceof FunctionValue; }
-    public static boolean isArray(Object val) { return val instanceof ArrayValue; }
     public static boolean isWrapper(Object val) { return val instanceof NativeWrapper; }
     public static boolean isWrapper(Object val, Class<?> clazz) {
         if (!isWrapper(val)) return false;
@@ -51,8 +70,7 @@ public class Values {
 
     @SuppressWarnings("unchecked")
     public static <T> T wrapper(Object val, Class<T> clazz) { 
-        if (!isWrapper(val)) return null;
-
+        if (!isWrapper(val)) val = new NativeWrapper(val);
         var res = (NativeWrapper)val;
         if (res != null && clazz.isInstance(res.wrapped)) return (T)res.wrapped;
         else return null;
@@ -71,8 +89,8 @@ public class Values {
     private static Object tryCallConvertFunc(Context ctx, Object obj, String name) {
         var func = getMember(ctx, obj, name);
 
-        if (func != null) {
-            var res = ((FunctionValue)func).call(ctx, obj);
+        if (func instanceof FunctionValue) {
+            var res = Values.call(ctx, func, obj);
             if (isPrimitive(res)) return res;
         }
 
@@ -105,7 +123,7 @@ public class Values {
     }
     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;
@@ -117,7 +135,7 @@ public class Values {
         if (val instanceof Boolean) return ((Boolean)val) ? 1 : 0;
         if (val instanceof String) {
             try { return Double.parseDouble((String)val); }
-            catch (Throwable e) { throw new UncheckedException(e); }
+            catch (NumberFormatException e) { return Double.NaN; }
         }
         return Double.NaN;
     }
@@ -136,7 +154,7 @@ 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";
     }
@@ -190,12 +208,18 @@ public class Values {
         return _a >>> _b;
     }
 
-    public static int compare(Context ctx, Object a, Object b) {
+    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) {
@@ -231,10 +255,10 @@ 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]);
@@ -259,7 +283,7 @@ public class Values {
         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.");
-        if (isObject(obj)) return object(obj).getMember(ctx, key);
+        if (obj instanceof ObjectValue) return ((ObjectValue)obj).getMember(ctx, key, obj);
 
         if (obj instanceof String && key instanceof Number) {
             var i = number(key);
@@ -271,16 +295,21 @@ 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 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 (isObject(obj)) return object(obj).setMember(ctx, key, val, false);
+        if (key != null && "__proto__".equals(key)) return setPrototype(ctx, obj, val);
+        if (obj instanceof ObjectValue) return ((ObjectValue)obj).setMember(ctx, key, val, obj, false);
 
         var proto = getPrototype(ctx, obj);
         return proto.setMember(ctx, key, val, obj, true);
@@ -289,8 +318,8 @@ public class Values {
         if (obj == null || obj == NULL) return false;
         obj = normalize(ctx, obj); key = normalize(ctx, key);
 
-        if (key.equals("__proto__")) return true;
-        if (isObject(obj)) return object(obj).hasMember(ctx, key, own);
+        if ("__proto__".equals(key)) return true;
+        if (obj instanceof ObjectValue) return object(obj).hasMember(ctx, key, own);
 
         if (obj instanceof String && key instanceof Number) {
             var i = number(key);
@@ -307,30 +336,35 @@ public class Values {
         if (obj == null || obj == NULL) return false;
         obj = normalize(ctx, obj); key = normalize(ctx, key);
 
-        if (isObject(obj)) return object(obj).deleteMember(ctx, key);
+        if (obj instanceof ObjectValue) return object(obj).deleteMember(ctx, key);
         else return false;
     }
     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 (obj instanceof ObjectValue) return ((ObjectValue)obj).getPrototype(ctx);
         if (ctx == null) return null;
 
-        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");
+        if (obj instanceof String) return ctx.get(Environment.STRING_PROTO);
+        else if (obj instanceof Number) return ctx.get(Environment.NUMBER_PROTO);
+        else if (obj instanceof Boolean) return ctx.get(Environment.BOOL_PROTO);
+        else if (obj instanceof Symbol) return ctx.get(Environment.SYMBOL_PROTO);
 
         return null;
     }
     public static boolean setPrototype(Context ctx, Object obj, Object proto) {
         obj = normalize(ctx, obj);
-        return isObject(obj) && object(obj).setPrototype(ctx, proto);
+        return obj instanceof ObjectValue && ((ObjectValue)obj).setPrototype(ctx, proto);
+    }
+    public static void makePrototypeChain(Context ctx, Object... chain) {
+        for(var i = 1; i < chain.length; i++) {
+            setPrototype(ctx, chain[i], chain[i - 1]);
+        }
     }
     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);
+        if (obj instanceof ObjectValue) res = object(obj).keys(includeNonEnumerable);
         if (obj instanceof String) {
             for (var i = 0; i < ((String)obj).length(); i++) res.add((double)i);
         }
@@ -340,7 +374,7 @@ public class Values {
 
             while (proto != null) {
                 res.addAll(proto.keys(includeNonEnumerable));
-                proto = proto.getPrototype(ctx);
+                proto = getPrototype(ctx, proto);
             }
         }
 
@@ -366,19 +400,24 @@ public class Values {
     }
 
     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.");
+        if (!(func instanceof FunctionValue)) 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) {
         var res = new ObjectValue();
+        try {
             var proto = Values.getMember(ctx, func, "prototype");
-        res.setPrototype(ctx, proto);
+            setPrototype(ctx, res, 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) {
         a = normalize(ctx, a); b = normalize(ctx, b);
@@ -441,7 +480,7 @@ public class Values {
 
         if (val instanceof Class) {
             if (ctx == null) return null;
-            else return ctx.environment().wrappers.getConstr((Class<?>)val);
+            else return ctx.environment.wrappers.getConstr((Class<?>)val);
         }
 
         return new NativeWrapper(val);
@@ -508,23 +547,26 @@ public class Values {
 
         if (obj == null) return null;
         if (clazz.isInstance(obj)) return (T)obj;
+        if (clazz.isAssignableFrom(NativeWrapper.class)) {
+            return (T)new NativeWrapper(obj);
+        }
 
         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.environment().symbol("Symbol.iterator");
+                var symbol = Symbol.get("Symbol.iterator");
 
                 var iteratorFunc = getMember(ctx, obj, symbol);
-                if (!isFunction(iteratorFunc)) return Collections.emptyIterator();
+                if (!(iteratorFunc instanceof FunctionValue)) return Collections.emptyIterator();
                 var iterator = iteratorFunc instanceof FunctionValue ?
                     ((FunctionValue)iteratorFunc).call(ctx, obj, obj) :
                     iteratorFunc;
                 var nextFunc = getMember(ctx, call(ctx, iteratorFunc, obj), "next");
 
-                if (!isFunction(nextFunc)) return Collections.emptyIterator();
+                if (!(nextFunc instanceof FunctionValue)) return Collections.emptyIterator();
 
                 return new Iterator<Object>() {
                     private Object value = null;
@@ -534,11 +576,11 @@ public class Values {
                     private void loadNext() {
                         if (next == null) value = null;
                         else if (consumed) {
-                            var curr = object(next.call(ctx, iterator));
+                            var curr = next.call(ctx, iterator);
                             if (curr == null) { next = null; value = null; }
-                            if (toBoolean(curr.getMember(ctx, "done"))) { next = null; value = null; }
+                            if (toBoolean(Values.getMember(ctx, curr, "done"))) { next = null; value = null; }
                             else {
-                                this.value = curr.getMember(ctx, "value");
+                                this.value = Values.getMember(ctx, curr, "value");
                                 consumed = false;
                             }
                         }
@@ -565,122 +607,165 @@ public class Values {
         };
     }
 
-    public static ObjectValue fromJavaIterator(Context ctx, Iterator<?> it) {
+    public static ObjectValue toJSIterator(Context ctx, Iterator<?> it) {
         var res = new ObjectValue();
 
         try {
-            var key = getMember(ctx, getMember(ctx, ctx.environment().proto("symbol"), "constructor"), "iterator");
-            res.defineProperty(ctx, key, new NativeFunction("", (_ctx, thisArg, args) -> thisArg));
+            var key = getMember(ctx, getMember(ctx, ctx.get(Environment.SYMBOL_PROTO), "constructor"), "iterator");
+            res.defineProperty(ctx, key, new NativeFunction("", args -> args.self));
         }
         catch (IllegalArgumentException | NullPointerException e) { }
 
-        res.defineProperty(ctx, "next", new NativeFunction("", (_ctx, _th, _args) -> {
+        res.defineProperty(ctx, "next", new NativeFunction("", 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(args.ctx, "value", it.next());
+                return obj;
+            }
         }));
 
         return res;
     }
 
-    public static ObjectValue fromJavaIterable(Context ctx, Iterable<?> it) {
-        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) {
-        if (passed.contains(val)) {
-            System.out.print("[circular]");
-            return;
+    public static ObjectValue toJSAsyncIterator(Context ctx, Iterator<?> it) {
+        var res = new ObjectValue();
+
+        try {
+            var key = getMemberPath(ctx, ctx.get(Environment.SYMBOL_PROTO), "constructor", "asyncIterator");
+            res.defineProperty(ctx, key, new NativeFunction("", args -> args.self));
         }
+        catch (IllegalArgumentException | NullPointerException e) { }
+
+        res.defineProperty(ctx, "next", new NativeFunction("", args -> {
+            return PromiseLib.await(args.ctx, () -> {
+                if (!it.hasNext()) return new ObjectValue(ctx, Map.of("done", true));
+                else {
+                    var obj = new ObjectValue();
+                    obj.defineProperty(args.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 String toReadable(Context ctx, Object val, HashSet<Object> passed, int tab) {
+        if (tab == 0 && val instanceof String) return (String)val;
+
+        if (passed.contains(val)) return "[circular]";
 
         var printed = true;
+        var res = new StringBuilder();
 
         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("(...)");
+            res.append(val.toString());
             var loc = val instanceof CodeFunction ? ((CodeFunction)val).loc() : null;
 
-            if (loc != null) System.out.print(" @ " + loc);
+            if (loc != null) res.append(" @ " + loc);
         }
         else if (val instanceof ArrayValue) {
-            System.out.print("[");
+            res.append("[");
             var obj = ((ArrayValue)val);
             for (int i = 0; i < obj.size(); i++) {
-                if (i != 0) System.out.print(", ");
-                else System.out.print(" ");
-                if (obj.has(i)) printValue(ctx, obj.get(i), passed, tab);
-                else System.out.print("<empty>");
+                if (i != 0) res.append(", ");
+                else res.append(" ");
+                if (obj.has(i)) res.append(toReadable(ctx, obj.get(i), passed, tab));
+                else res.append("<empty>");
             }
-            System.out.print(" ] ");
+            res.append(" ] ");
         }
         else if (val instanceof NativeWrapper) {
             var obj = ((NativeWrapper)val).wrapped;
-            System.out.print("Native " + obj.toString() + " ");
+            res.append("Native " + obj.toString() + " ");
         }
         else printed = false;
 
         if (val instanceof ObjectValue) {
             if (tab > 3) {
-                System.out.print("{...}");
-                return;
+                return "{...}";
             }
+
             passed.add(val);
 
             var obj = (ObjectValue)val;
-            if (obj.values.size() + obj.properties.size() == 0) {
-                if (!printed) System.out.println("{}");
+            if (obj.values.size() + obj.properties.size() == 0 || isEmptyFunc(obj)) {
+                if (!printed) res.append("{}\n");
             }
             else {
-                System.out.println("{");
+                res.append("{\n");
 
                 for (var el : obj.values.entrySet()) {
                     for (int i = 0; i < tab + 1; i++) System.out.print("    ");
-                    printValue(ctx, el.getKey(), passed, tab + 1);
-                    System.out.print(": ");
-                    printValue(ctx, el.getValue(), passed, tab + 1);
-                    System.out.println(",");
+                    res.append(toReadable(ctx, el.getKey(), passed, tab + 1));
+                    res.append(": ");
+                    res.append(toReadable(ctx, el.getValue(), passed, tab + 1));
+                    res.append(",\n");
                 }
                 for (var el : obj.properties.entrySet()) {
                     for (int i = 0; i < tab + 1; i++) System.out.print("    ");
-                    printValue(ctx, el.getKey(), passed, tab + 1);
-                    System.out.println(": [prop],");
+                    res.append(toReadable(ctx, el.getKey(), passed, tab + 1));
+                    res.append(": [prop],\n");
                 }
 
-                for (int i = 0; i < tab; i++) System.out.print("    ");
-                System.out.print("}");
+                for (int i = 0; i < tab; i++) res.append("    ");
+                res.append("}");
+            }
 
             passed.remove(val);
         }
+        else if (val == null) return "undefined";
+        else if (val == Values.NULL) return "null";
+        else if (val instanceof String) return "'" + val + "'";
+        else return Values.toString(ctx, val);
+
+        return res.toString();
     }
-        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 String toReadable(Context ctx, Object val) {
+        return toReadable(ctx, val, new HashSet<>(), 0);
     }
-    public static void printValue(Context ctx, Object val) {
-        printValue(ctx, val, new HashSet<>(), 0);
-    }
-    public static void printError(RuntimeException err, String prefix) {
+    public static String errorToReadable(RuntimeException err, String prefix) {
         prefix = prefix == null ? "Uncaught" : "Uncaught " + prefix;
-        try {
         if (err instanceof EngineException) {
             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);
-            }
-            else if (err.getCause() instanceof InterruptedException) return;
-            else {
-                System.out.println("Internal error ocurred:");
-                err.printStackTrace();
-            }
+            try {
+                return prefix + " " + ee.toString(new Context(ee.engine, ee.env));
             }
             catch (EngineException ex) {
-            System.out.println("Uncaught ");
-            Values.printValue(null, ((EngineException)err).value);
-            System.out.println();
+                return prefix + " " + toReadable(new Context(ee.engine, ee.env), ee.value);
             }
         }
+        else if (err instanceof SyntaxException) {
+            return prefix + " SyntaxError " + ((SyntaxException)err).msg;
+        }
+        else if (err.getCause() instanceof InterruptedException) return "";
+        else {
+            var str = new ByteArrayOutputStream();
+            err.printStackTrace(new PrintStream(str));
+
+            return prefix + " internal error " + str.toString();
+        }
+    }
+    public static void printValue(Context ctx, Object val) {
+        System.out.print(toReadable(ctx, val));
+    }
+    public static void printError(RuntimeException err, String prefix) {
+        System.out.println(errorToReadable(err, prefix));
+    }
 }

src/java/me/topchetoeu/jscript/core/exceptions/ConvertException.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.exceptions;
+package me.topchetoeu.jscript.core.exceptions;
 
 public class ConvertException extends RuntimeException {
     public final String source, target;

src/java/me/topchetoeu/jscript/core/exceptions/EngineException.java

@@ -0,0 +1,123 @@
+package me.topchetoeu.jscript.core.exceptions;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.engine.Context;
+import me.topchetoeu.jscript.core.engine.Engine;
+import me.topchetoeu.jscript.core.engine.Environment;
+import me.topchetoeu.jscript.core.engine.debug.DebugContext;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue;
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.core.engine.values.ObjectValue.PlaceholderProto;
+
+public class EngineException extends RuntimeException {
+    public static class StackElement {
+        public final Location location;
+        public final String function;
+        public final Context ctx;
+
+        public boolean visible() {
+            return ctx == null || !ctx.get(Environment.HIDE_STACK, false);
+        }
+        public String toString() {
+            var res = "";
+            var loc = location;
+
+            if (loc != null && ctx != null && ctx.engine != null) loc = DebugContext.get(ctx).mapToCompiled(loc);
+
+            if (loc != null) res += "at " + loc.toString() + " ";
+            if (function != null && !function.equals("")) res += "in " + function + " ";
+
+            return res.trim();
+        }
+
+        public StackElement(Context ctx, Location location, String function) {
+            if (function != null) function = function.trim();
+            if (function.equals("")) function = null;
+
+            if (ctx == null) this.ctx = null;
+            else this.ctx = new Context(ctx.engine, ctx.environment);
+            this.location = location;
+            this.function = function;
+        }
+    }
+
+    public final Object value;
+    public EngineException cause;
+    public Environment env = null;
+    public Engine engine = null;
+    public final List<StackElement> stackTrace = new ArrayList<>();
+
+    public EngineException add(Context ctx, String name, Location location) {
+        var el = new StackElement(ctx, location, name);
+        if (el.function == null && el.location == null) return this;
+        setCtx(ctx.environment, ctx.engine);
+        stackTrace.add(el);
+        return this;
+    }
+    public EngineException setCause(EngineException cause) {
+        this.cause = cause;
+        return this;
+    }
+    public EngineException setCtx(Environment env, Engine engine) {
+        if (this.env == null) this.env = env;
+        if (this.engine == null) this.engine = engine;
+        return this;
+    }
+    public EngineException setCtx(Context ctx) {
+        if (this.env == null) this.env = ctx.environment;
+        if (this.engine == null) this.engine = ctx.engine;
+        return this;
+    }
+
+    public String toString(Context ctx) {
+        var ss = new StringBuilder();
+        try {
+            ss.append(Values.toString(ctx, value)).append('\n');
+        }
+        catch (EngineException e) {
+            ss.append("[Error while stringifying]\n");
+        }
+        for (var line : stackTrace) {
+            if (line.visible()) ss.append("    ").append(line.toString()).append("\n");
+        }
+        if (cause != null) ss.append("Caused by ").append(cause.toString(ctx)).append('\n');
+        ss.deleteCharAt(ss.length() - 1);
+        return ss.toString();
+    }
+
+    private static Object err(String name, String msg, PlaceholderProto proto) {
+        var res = new ObjectValue(proto);
+        if (name != null) res.defineProperty(null, "name", name);
+        res.defineProperty(null, "message", msg);
+        return res;
+    }
+
+    public EngineException(Object error) {
+        super(error == null ? "null" : error.toString());
+
+        this.value = error;
+        this.cause = null;
+    }
+
+    public static EngineException ofError(String name, String msg) {
+        return new EngineException(err(name, msg, PlaceholderProto.ERROR));
+    }
+    public static EngineException ofError(String msg) {
+        return new EngineException(err(null, msg, PlaceholderProto.ERROR));
+    }
+    public static EngineException ofSyntax(SyntaxException e) {
+        return new EngineException(err(null, e.msg, PlaceholderProto.SYNTAX_ERROR)).add(null, null, e.loc);
+    }
+    public static EngineException ofSyntax(String msg) {
+        return new EngineException(err(null, msg, PlaceholderProto.SYNTAX_ERROR));
+    }
+    public static EngineException ofType(String msg) {
+        return new EngineException(err(null, msg, PlaceholderProto.TYPE_ERROR));
+    }
+    public static EngineException ofRange(String msg) {
+        return new EngineException(err(null, msg, PlaceholderProto.RANGE_ERROR));
+    }
+}

src/java/me/topchetoeu/jscript/core/exceptions/InterruptException.java

@@ -1,4 +1,4 @@
-package me.topchetoeu.jscript.exceptions;
+package me.topchetoeu.jscript.core.exceptions;
 
 public class InterruptException extends RuntimeException {
     public InterruptException() { }

src/java/me/topchetoeu/jscript/core/exceptions/SyntaxException.java

@@ -1,6 +1,6 @@
-package me.topchetoeu.jscript.exceptions;
+package me.topchetoeu.jscript.core.exceptions;
 
-import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.common.Location;
 
 public class SyntaxException extends RuntimeException {
     public final Location loc;

src/java/me/topchetoeu/jscript/core/parsing/Operator.java

@@ -1,9 +1,9 @@
-package me.topchetoeu.jscript.parsing;
+package me.topchetoeu.jscript.core.parsing;
 
 import java.util.HashMap;
 import java.util.Map;
 
-import me.topchetoeu.jscript.engine.Operation;
+import me.topchetoeu.jscript.core.engine.Operation;
 
 public enum Operator {
     MULTIPLY("*", Operation.MULTIPLY, 13),

src/java/me/topchetoeu/jscript/core/parsing/ParseRes.java

@@ -1,10 +1,10 @@
-package me.topchetoeu.jscript.parsing;
+package me.topchetoeu.jscript.core.parsing;
 
 import java.util.List;
 import java.util.Map;
 
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.parsing.Parsing.Parser;
+import me.topchetoeu.jscript.common.Location;
+import me.topchetoeu.jscript.core.parsing.Parsing.Parser;
 
 public class ParseRes<T> {
     public static enum State {
@@ -69,6 +69,9 @@ public class ParseRes<T> {
 
     @SafeVarargs
     public static <T> ParseRes<? extends T> any(ParseRes<? extends T> ...parsers) {
+        return any(List.of(parsers));
+    }
+    public static <T> ParseRes<? extends T> any(List<ParseRes<? extends T>> parsers) {
         ParseRes<? extends T> best = null;
         ParseRes<? extends T> error = ParseRes.failed();