feat: fully implement local and capture scope object wrappers

feat: implement object sending and receiving

src/assets/index.html

@@ -16,14 +16,15 @@
     <p>
         Here are the available entrypoints:
         <ul>
-            <li><a href="json/version">/json/version</a></li>
+            <li><a href="json/version">/json/version</a> - version and other stuff about the JScript engine</li>
-            <li><a href="json/list">/json/list</a></li>
+            <li><a href="json/list">/json/list</a> - a list of all entrypoints</li>
-            <li>/(any target)</a></li>
+            <li><a href="json/protocol">/json/protocol</a> - documentation of the implemented V8 protocol</li>
+            <li>/(any target) - websocket entrypoints for debugging</li>
         </ul>
     </p>
 
     <p>
-        Developed by TopchetoEU, MIT License
+        Running ${NAME} v${VERSION} by ${AUTHOR}
     </p>
 </body>
 </html>

src/assets/protocol.json

@@ -1957,6 +1957,51 @@
                     ]
                 }
             ]
+        },
+        {
+            "domain": "NodeWorker",
+            "description": "Implemented partly just because of pesky vscode.",
+            "deprecated": true,
+            "commands": [
+                {
+                    "name": "enable",
+                    "description": "Used to get the attachedToWorker event",
+                    "parameters": [ ]
+                }
+            ],
+            "events": [
+                {
+                    "name": "attachedToWorker",
+                    "description": "Issued when attached to a worker.",
+                    "parameters": [
+                        { "name": "sessionId",
+                            "description": "Identifier assigned to the session used to send/receive messages.",
+                            "$ref": "string"
+                        },
+                        {
+                            "name": "workerInfo",
+                            "type": "object",
+                            "properties": [
+                                { "name": "workerId",
+                                    "$ref": "string"
+                                },
+                                { "name": "type",
+                                    "type": "string"
+                                },
+                                { "name": "title",
+                                    "type": "string"
+                                },
+                                { "name": "url",
+                                    "type": "string"
+                                }
+                            ]
+                        },
+                        { "name": "waitingForDebugger",
+                            "type": "boolean"
+                        }
+                    ]
+                }
+            ]
         }
     ]
 }

src/me/topchetoeu/jscript/Main.java

@@ -23,6 +23,7 @@ public class Main {
     static Thread engineTask, debugTask;
     static Engine engine;
     static Environment env;
+    static int j = 0;
 
     private static Observer<Object> valuePrinter = new Observer<Object>() {
         public void next(Object data) {
@@ -59,7 +60,7 @@ public class Main {
             env.global.define("go", _ctx -> {
                 try {
                     var f = Path.of("do.js");
-                    var func = _ctx.compile(Filename.fromFile(f.toFile()), new String(Files.readAllBytes(f)));
+                    var func = _ctx.compile(new Filename("do", "do/" + j++ + ".js"), new String(Files.readAllBytes(f)));
                     return func.call(_ctx);
                 }
                 catch (IOException e) {

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

@@ -8,7 +8,7 @@ import me.topchetoeu.jscript.Location;
 
 public class CompileTarget {
     public final Vector<Instruction> target = new Vector<>();
-    public final Map<Long, Instruction[]> functions;
+    public final Map<Long, FunctionBody> functions;
     public final TreeSet<Location> breakpoints;
 
     public Instruction add(Instruction instr) {
@@ -31,7 +31,7 @@ public class CompileTarget {
 
     public Instruction[] array() { return target.toArray(Instruction[]::new); }
 
-    public CompileTarget(Map<Long, Instruction[]> functions, TreeSet<Location> breakpoints) {
+    public CompileTarget(Map<Long, FunctionBody> functions, TreeSet<Location> breakpoints) {
         this.functions = functions;
         this.breakpoints = breakpoints;
     }

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

@@ -11,6 +11,7 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 
 public class CompoundStatement extends Statement {
     public final Statement[] statements;
+    public Location end;
 
     @Override
     public void declare(ScopeRecord varsScope) {
@@ -32,11 +33,16 @@ public class CompoundStatement extends Statement {
 
         for (var i = 0; i < statements.length; i++) {
             var stm = statements[i];
-            
+
             if (stm instanceof FunctionStatement) continue;
             if (i != statements.length - 1) stm.compileWithDebug(target, scope, false);
             else stm.compileWithDebug(target, scope, pollute);
         }
+
+        if (end != null) {
+            target.add(Instruction.nop().locate(end));
+            target.setDebug();
+        }
     }
 
     @Override
@@ -59,6 +65,11 @@ public class CompoundStatement extends Statement {
         else return new CompoundStatement(loc(), res.toArray(Statement[]::new));
     }
 
+    public CompoundStatement setEnd(Location loc) {
+        this.end = loc;
+        return this;
+    }
+
     public CompoundStatement(Location loc, Statement ...statements) {
         super(loc);
         this.statements = statements;

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

@@ -0,0 +1,17 @@
+package me.topchetoeu.jscript.compilation;
+
+public class FunctionBody {
+    public final Instruction[] instructions;
+    public final String[] captureNames, localNames;
+
+    public FunctionBody(Instruction[] instructions, String[] captureNames, String[] localNames) {
+        this.instructions = instructions;
+        this.captureNames = captureNames;
+        this.localNames = localNames;
+    }
+    public FunctionBody(Instruction[] instructions) {
+        this.instructions = instructions;
+        this.captureNames = new String[0];
+        this.localNames = new String[0];
+    }
+}

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

@@ -147,14 +147,6 @@ public class Instruction {
     public static Instruction debug() {
         return new Instruction(null, Type.NOP, "debug");
     }
-    public static Instruction debugVarNames(String[] names) {
-        var args = new Object[names.length + 1];
-        args[0] = "dbg_vars";
-
-        System.arraycopy(names, 0, args, 1, names.length);
-
-        return new Instruction(null, Type.NOP, args);
-    }
 
     public static Instruction nop(Object ...params) {
         for (var param : params) {

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

@@ -10,10 +10,12 @@ public class VariableDeclareStatement extends Statement {
     public static class Pair {
         public final String name;
         public final Statement value;
+        public final Location location;
 
-        public Pair(String name, Statement value) {
+        public Pair(String name, Statement value, Location location) {
             this.name = name;
             this.value = value;
+            this.location = location;
         }
     }
 
@@ -30,16 +32,20 @@ public class VariableDeclareStatement extends Statement {
         for (var entry : values) {
             if (entry.name == null) continue;
             var key = scope.getKey(entry.name);
-            if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(loc()));
+            int start = target.size();
+
+            if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(entry.location));
 
             if (entry.value instanceof FunctionStatement) {
                 ((FunctionStatement)entry.value).compile(target, scope, entry.name, false);
-                target.add(Instruction.storeVar(key).locate(loc()));
+                target.add(Instruction.storeVar(key).locate(entry.location));
             }
             else if (entry.value != null) {
                 entry.value.compile(target, scope, true);
-                target.add(Instruction.storeVar(key).locate(loc()));
+                target.add(Instruction.storeVar(key).locate(entry.location));
             }
+
+            if (target.size() != start) target.setDebug(start);
         }
 
         if (pollute) target.add(Instruction.loadValue(null).locate(loc()));

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

@@ -16,7 +16,7 @@ public class CallStatement extends Statement {
             ((IndexStatement)func).compile(target, scope, true, true);
         }
         else {
-               target.add(Instruction.loadValue(null).locate(loc()));
+            target.add(Instruction.loadValue(null).locate(loc()));
             func.compile(target, scope, true);
         }
 

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

@@ -5,6 +5,7 @@ import java.util.Random;
 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.compilation.CompileTarget;
 import me.topchetoeu.jscript.compilation.CompoundStatement;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
 import me.topchetoeu.jscript.compilation.Instruction.Type;
@@ -69,7 +70,6 @@ public class FunctionStatement extends Statement {
         }
 
         body.declare(subscope);
-        funcTarget.add(Instruction.debugVarNames(subscope.locals()));
         body.compile(funcTarget, subscope, false);
         funcTarget.add(Instruction.ret().locate(loc()));
         checkBreakAndCont(funcTarget, start);
@@ -77,7 +77,7 @@ public class FunctionStatement extends Statement {
         var id = rand.nextLong();
 
         target.add(Instruction.loadFunc(id, subscope.localsCount(), args.length, subscope.getCaptures()).locate(loc()));
-        target.functions.put(id, funcTarget.array());
+        target.functions.put(id, new FunctionBody(funcTarget.array(), subscope.captures(), subscope.locals()));
 
         if (name == null) name = this.name;
 

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

@@ -20,17 +20,17 @@ public class IndexStatement extends AssignableStatement {
         return new IndexAssignStatement(loc(), object, index, val, operation);
     }
     public void compile(CompileTarget target, ScopeRecord scope, boolean dupObj, boolean pollute) {
-        int start = 0;
         object.compile(target, scope, true);
         if (dupObj) target.add(Instruction.dup().locate(loc()));
         if (index instanceof ConstantStatement) {
             target.add(Instruction.loadMember(((ConstantStatement)index).value).locate(loc()));
+            target.setDebug();
             return;
         }
 
         index.compile(target, scope, true);
         target.add(Instruction.loadMember().locate(loc()));
-        target.setDebug(start);
+        target.setDebug();
         if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
     @Override

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

@@ -4,7 +4,7 @@ import java.util.HashMap;
 import java.util.concurrent.LinkedBlockingDeque;
 
 import me.topchetoeu.jscript.Filename;
-import me.topchetoeu.jscript.compilation.Instruction;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
 import me.topchetoeu.jscript.events.Awaitable;
 import me.topchetoeu.jscript.events.DataNotifier;
@@ -51,7 +51,7 @@ public class Engine {
     private LinkedBlockingDeque<Task> microTasks = new LinkedBlockingDeque<>();
 
     public final int id = ++nextId;
-    public final HashMap<Long, Instruction[]> functions = new HashMap<>();
+    public final HashMap<Long, FunctionBody> functions = new HashMap<>();
     public final Data data = new Data().set(StackData.MAX_FRAMES, 10000);
 
     private void runTask(Task task) {
@@ -63,8 +63,8 @@ public class Engine {
             task.notifier.error(e);
         }
     }
-    private void run() {
+    public void run(boolean untilEmpty) {
-        while (true) {
+        while (!untilEmpty || !macroTasks.isEmpty()) {
             try {
                 runTask(macroTasks.take());
 
@@ -83,7 +83,7 @@ public class Engine {
 
     public Thread start() {
         if (this.thread == null) {
-            this.thread = new Thread(this::run, "JavaScript Runner #" + id);
+            this.thread = new Thread(() -> run(false), "JavaScript Runner #" + id);
             this.thread.start();
         }
         return this.thread;

src/me/topchetoeu/jscript/engine/debug/DebugHandler.java

@@ -20,4 +20,16 @@ public interface DebugHandler {
     void stepOver(V8Message msg);
 
     void setPauseOnExceptions(V8Message msg);
+
+    void evaluateOnCallFrame(V8Message msg);
+
+    void getProperties(V8Message msg);
+    void releaseObjectGroup(V8Message msg);
+    /**
+     * This method might not execute the actual code for well-known requests
+     */
+    void callFunctionOn(V8Message msg);
+
+    // void nodeWorkerEnable(V8Message msg);
+    void runtimeEnable(V8Message msg);
 }

src/me/topchetoeu/jscript/engine/debug/DebugServer.java

@@ -8,6 +8,7 @@ import java.security.MessageDigest;
 import java.util.Base64;
 import java.util.HashMap;
 
+import me.topchetoeu.jscript.Metadata;
 import me.topchetoeu.jscript.engine.debug.WebSocketMessage.Type;
 import me.topchetoeu.jscript.exceptions.SyntaxException;
 import me.topchetoeu.jscript.exceptions.UncheckedException;
@@ -17,11 +18,11 @@ import me.topchetoeu.jscript.json.JSONList;
 import me.topchetoeu.jscript.json.JSONMap;
 
 public class DebugServer {
-    public static String browserDisplayName = "jscript";
+    public static String browserDisplayName = Metadata.NAME + "/" + Metadata.VERSION;
 
     public final HashMap<String, DebuggerProvider> targets = new HashMap<>();
 
-    private final byte[] favicon, index;
+    private final byte[] favicon, index, protocol;
 
     private static void send(HttpRequest req, String val) throws IOException {
         req.writeResponse(200, "OK", "application/json", val.getBytes());
@@ -58,7 +59,7 @@ public class DebugServer {
 
             try {
                 msg = new V8Message(raw.textData());
-                System.out.println(msg.name + ": " + JSON.stringify(msg.params));
+                // System.out.println(msg.name + ": " + JSON.stringify(msg.params));
             }
             catch (SyntaxException e) {
                 ws.send(new V8Error(e.getMessage()));
@@ -86,6 +87,13 @@ public class DebugServer {
                     case "Debugger.stepOver": debugger.stepOver(msg); continue;
 
                     case "Debugger.setPauseOnExceptions": debugger.setPauseOnExceptions(msg); continue;
+                    case "Debugger.evaluateOnCallFrame": debugger.evaluateOnCallFrame(msg); continue;
+
+                    case "Runtime.releaseObjectGroup": debugger.releaseObjectGroup(msg); continue;
+                    case "Runtime.getProperties": debugger.getProperties(msg); continue;
+                    case "Runtime.callFunctionOn": debugger.callFunctionOn(msg); continue;
+                    // case "NodeWorker.enable": debugger.nodeWorkerEnable(msg); continue;
+                    case "Runtime.enable": debugger.runtimeEnable(msg); continue;
                 }
 
                 if (
@@ -96,8 +104,7 @@ public class DebugServer {
                     msg.name.startsWith("Network.") ||
                     msg.name.startsWith("Page.")
                 ) ws.send(new V8Error("This isn't a browser..."));
-
+                else ws.send(new V8Error("This API is not supported yet."));
-                if (msg.name.startsWith("Runtime.") || msg.name.startsWith("Profiler.")) ws.send(new V8Error("This API is not supported yet."));
             }
             catch (Throwable e) {
                 e.printStackTrace();
@@ -158,7 +165,7 @@ public class DebugServer {
     
                     switch (req.path) {
                         case "/json/version":
-                            send(req, "{\"Browser\":\"" + browserDisplayName + "\",\"Protocol-Version\":\"1.2\"}");
+                            send(req, "{\"Browser\":\"" + browserDisplayName + "\",\"Protocol-Version\":\"1.1\"}");
                             break;
                         case "/json/list":
                         case "/json": {
@@ -176,9 +183,11 @@ public class DebugServer {
                             send(req, JSON.stringify(res));
                             break;
                         }
+                        case "/json/protocol":
+                            req.writeResponse(200, "OK", "application/json", protocol);
+                            break;
                         case "/json/new":
                         case "/json/activate":
-                        case "/json/protocol":
                         case "/json/close":
                         case "/devtools/inspector.html":
                             req.writeResponse(
@@ -216,7 +225,13 @@ public class DebugServer {
     public DebugServer() {
         try {
             this.favicon = getClass().getClassLoader().getResourceAsStream("assets/favicon.png").readAllBytes();
-            this.index = getClass().getClassLoader().getResourceAsStream("assets/index.html").readAllBytes();
+            this.protocol = getClass().getClassLoader().getResourceAsStream("assets/protocol.json").readAllBytes();
+            var index = new String(getClass().getClassLoader().getResourceAsStream("assets/index.html").readAllBytes());
+            this.index = index
+                .replace("${NAME}", Metadata.NAME)
+                .replace("${VERSION}", Metadata.VERSION)
+                .replace("${AUTHOR}", Metadata.AUTHOR)
+                .getBytes();
         }
         catch (IOException e) { throw new UncheckedIOException(e); }
     }

src/me/topchetoeu/jscript/engine/debug/HttpRequest.java

@@ -10,8 +10,6 @@ import java.util.HashMap;
 import java.util.IllegalFormatException;
 import java.util.Map;
 
-import me.topchetoeu.jscript.exceptions.UncheckedIOException;
-
 public class HttpRequest {
     public final String method;
     public final String path;
@@ -21,19 +19,19 @@ public class HttpRequest {
 
     public void writeCode(int code, String name) {
         try { out.write(("HTTP/1.1 " + code + " " + name + "\r\n").getBytes()); }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
     public void writeHeader(String name, String value) {
         try { out.write((name + ": " + value + "\r\n").getBytes()); }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
     public void writeLastHeader(String name, String value) {
         try { out.write((name + ": " + value + "\r\n\r\n").getBytes()); }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
     public void writeHeadersEnd() {
         try { out.write("\n".getBytes()); }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
 
     public void writeResponse(int code, String name, String type, byte[] data) {
@@ -44,13 +42,13 @@ public class HttpRequest {
             out.write(data);
             out.close();
         }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
     public void writeResponse(int code, String name, String type, InputStream data) {
         try {
             writeResponse(code, name, type, data.readAllBytes());
         }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException e) { }
     }
 
     public HttpRequest(String method, String path, Map<String, String> headers, OutputStream out) {
@@ -98,7 +96,7 @@ public class HttpRequest {
 
             return new HttpRequest(method, path, headers, socket.getOutputStream());
         }
-        catch (IOException e) { throw new UncheckedIOException(e); }
+        catch (IOException | NullPointerException e) { return null; }
     }
 }
 

src/me/topchetoeu/jscript/engine/debug/SimpleDebugger.java

@@ -3,9 +3,11 @@ package me.topchetoeu.jscript.engine.debug;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Random;
 import java.util.TreeSet;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 import me.topchetoeu.jscript.Filename;
 import me.topchetoeu.jscript.Location;
@@ -16,6 +18,7 @@ import me.topchetoeu.jscript.engine.Engine;
 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.GlobalScope;
 import me.topchetoeu.jscript.engine.values.ArrayValue;
 import me.topchetoeu.jscript.engine.values.CodeFunction;
 import me.topchetoeu.jscript.engine.values.FunctionValue;
@@ -24,6 +27,7 @@ import me.topchetoeu.jscript.engine.values.Symbol;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.events.Notifier;
 import me.topchetoeu.jscript.exceptions.EngineException;
+import me.topchetoeu.jscript.json.JSON;
 import me.topchetoeu.jscript.json.JSONElement;
 import me.topchetoeu.jscript.json.JSONList;
 import me.topchetoeu.jscript.json.JSONMap;
@@ -35,6 +39,8 @@ import me.topchetoeu.jscript.lib.SetLib;
 import me.topchetoeu.jscript.lib.GeneratorLib.Generator;
 
 public class SimpleDebugger implements Debugger {
+    public static final String CHROME_GET_PROP_FUNC = "function s(e){let t=this;const n=JSON.parse(e);for(let e=0,i=n.length;e<i;++e)t=t[n[e]];return t}";
+
     private static enum State {
         RESUMED,
         STEPPING_IN,
@@ -84,6 +90,7 @@ public class SimpleDebugger implements Debugger {
             this.pattern = pattern;
             this.line = line;
             this.start = start;
+            if (condition != null && condition.trim().equals("")) condition = null;
             this.condition = condition;
         }
     }
@@ -91,9 +98,10 @@ public class SimpleDebugger implements Debugger {
         public CodeFrame frame;
         public CodeFunction func;
         public int id;
-        public ObjectValue local = new ObjectValue(), capture = new ObjectValue(), global;
+        public ObjectValue local, capture, global;
         public JSONMap serialized;
         public Location location;
+        public boolean debugData = false;
 
         public void updateLoc(Location loc) {
             serialized.set("location", serializeLocation(loc));
@@ -108,22 +116,40 @@ public class SimpleDebugger implements Debugger {
             this.location = frame.function.loc();
 
             this.global = frame.function.environment.global.obj;
-            frame.scope.applyToObject(ctx, this.local, this.capture, true);
+            this.local = frame.getLocalScope(ctx, true);
+            this.capture = frame.getCaptureScope(ctx, true);
+            this.local.setPrototype(ctx, capture);
+            this.capture.setPrototype(ctx, global);
 
-            this.serialized = new JSONMap()
+            if (location != null) {
-                .set("callFrameId", id + "")
+                debugData = true;
-                .set("functionName", func.name)
+                this.serialized = new JSONMap()
-                .set("location", serializeLocation(func.loc()))
+                    .set("callFrameId", id + "")
-                .set("scopeChain", new JSONList()
+                    .set("functionName", func.name)
-                    .add(new JSONMap().set("type", "local").set("name", "Local Scope").set("object", serializeObj(ctx, local)))
+                    .set("location", serializeLocation(location))
-                    .add(new JSONMap().set("type", "closure").set("name", "Closure").set("object", serializeObj(ctx, capture)))
+                    .set("scopeChain", new JSONList()
-                    .add(new JSONMap().set("type", "global").set("name", "Global Scope").set("object", serializeObj(ctx, global)))
+                        .add(new JSONMap().set("type", "local").set("name", "Local Scope").set("object", serializeObj(ctx, local)))
-                )
+                        .add(new JSONMap().set("type", "closure").set("name", "Closure").set("object", serializeObj(ctx, capture)))
-                .setNull("this");
+                        .add(new JSONMap().set("type", "global").set("name", "Global Scope").set("object", serializeObj(ctx, global)))
+                    )
+                    .setNull("this");
+            }
         }
     }
 
-    public boolean enabled = false;
+    private class RunResult {
+        public final Context ctx;
+        public final Object result;
+        public final EngineException error;
+
+        public RunResult(Context ctx, Object result, EngineException error) {
+            this.ctx = ctx;
+            this.result = result;
+            this.error = error;
+        }
+    }
+
+    public boolean enabled = true;
     public CatchType execptionType = CatchType.ALL; 
     public State state = State.RESUMED;
 
@@ -145,6 +171,8 @@ public class SimpleDebugger implements Debugger {
 
     private HashMap<Integer, ObjectValue> idToObject = new HashMap<>();
     private HashMap<ObjectValue, Integer> objectToId = new HashMap<>();
+    private HashMap<ObjectValue, Context> objectToCtx = new HashMap<>();
+    private HashMap<String, ArrayList<ObjectValue>> objectGroups = new HashMap<>();
 
     private Notifier updateNotifier = new Notifier(); 
 
@@ -191,19 +219,19 @@ public class SimpleDebugger implements Debugger {
 
         return tail.first();
     }
-    public Location deserializeLocation(JSONElement el, boolean correct) {
+    private Location deserializeLocation(JSONElement el, boolean correct) {
         if (!el.isMap()) throw new RuntimeException("Expected location to be a map.");
         var id = Integer.parseInt(el.map().string("scriptId"));
         var line = (int)el.map().number("lineNumber") + 1;
         var column = (int)el.map().number("columnNumber") + 1;
 
-        if (!idToSource.containsKey(id)) throw new RuntimeException("The specified source %s doesn't exist.".formatted(id));
+        if (!idToSource.containsKey(id)) throw new RuntimeException(String.format("The specified source %s doesn't exist.", id));
 
         var res = new Location(line, column, idToSource.get(id).filename);
         if (correct) res = correctLocation(idToSource.get(id), res);
         return res;
     }
-    public JSONMap serializeLocation(Location loc) {
+    private JSONMap serializeLocation(Location loc) {
         var source = filenameToId.get(loc.filename());
         return new JSONMap()
             .set("scriptId", source + "")
@@ -211,21 +239,21 @@ public class SimpleDebugger implements Debugger {
             .set("columnNumber", loc.start() - 1);
     }
 
-    private Integer objectId(ObjectValue obj) {
+    private Integer objectId(Context ctx, ObjectValue obj) {
         if (objectToId.containsKey(obj)) return objectToId.get(obj);
         else {
             int id = nextId();
             objectToId.put(obj, id);
+            if (ctx != null) objectToCtx.put(obj, ctx);
             idToObject.put(id, obj);
             return id;
         }
     }
-    private JSONMap serializeObj(Context ctx, Object val) {
+    private JSONMap serializeObj(Context ctx, Object val, boolean recurse) {
         val = Values.normalize(null, val);
 
         if (val == Values.NULL) {
             return new JSONMap()
-                .set("objectId", objectId(null) + "")
                 .set("type", "object")
                 .set("subtype", "null")
                 .setNull("value")
@@ -234,13 +262,14 @@ public class SimpleDebugger implements Debugger {
 
         if (val instanceof ObjectValue) {
             var obj = (ObjectValue)val;
-            var id = objectId(obj);
+            var id = objectId(ctx, obj);
             var type = "object";
             String subtype = null;
             String className = null;
 
             if (obj instanceof FunctionValue) type = "function";
             if (obj instanceof ArrayValue) subtype = "array";
+
             if (Values.isWrapper(val, RegExpLib.class)) subtype = "regexp";
             if (Values.isWrapper(val, DateLib.class)) subtype = "date";
             if (Values.isWrapper(val, MapLib.class)) subtype = "map";
@@ -253,10 +282,13 @@ public class SimpleDebugger implements Debugger {
 
             var res = new JSONMap()
                 .set("type", type)
-                .set("objetId", id + "");
+                .set("objectId", id + "");
 
             if (subtype != null) res.set("subtype", subtype);
-            if (className != null) res.set("className", className);
+            if (className != null) {
+                res.set("className", className);
+                res.set("description", "{ " + className + " }");
+            }
 
             return res;
         }
@@ -271,7 +303,7 @@ public class SimpleDebugger implements Debugger {
 
             if (Double.POSITIVE_INFINITY == num) res.set("unserializableValue", "Infinity");
             else if (Double.NEGATIVE_INFINITY == num) res.set("unserializableValue", "-Infinity");
-            else if (num == -0.) res.set("unserializableValue", "-0");
+            else if (Double.doubleToRawLongBits(num) == Double.doubleToRawLongBits(-0d)) res.set("unserializableValue", "-0");
             else if (Double.isNaN(num)) res.set("unserializableValue", "NaN");
             else res.set("value", num);
 
@@ -280,6 +312,37 @@ public class SimpleDebugger implements Debugger {
 
         throw new IllegalArgumentException("Unexpected JS object.");
     }
+    private JSONMap serializeObj(Context ctx, Object val) {
+        return serializeObj(ctx, val, true);
+    }
+    private void setObjectGroup(String name, Object val) {
+        if (val instanceof ObjectValue) {
+            var obj = (ObjectValue)val;
+
+            if (objectGroups.containsKey(name)) objectGroups.get(name).add(obj);
+            else objectGroups.put(name, new ArrayList<>(List.of(obj)));
+        }
+    }
+    private void releaseGroup(String name) {
+        var objs = objectGroups.remove(name);
+
+        if (objs != null) {
+            for (var obj : objs) {
+                var id = objectToId.remove(obj);
+                if (id != null) idToObject.remove(id);
+            }
+        }
+    }
+    private Object deserializeArgument(JSONMap val) {
+        if (val.isString("objectId")) return idToObject.get(Integer.parseInt(val.string("objectId")));
+        else if (val.isString("unserializableValue")) switch (val.string("unserializableValue")) {
+            case "NaN": return Double.NaN;
+            case "-Infinity": return Double.NEGATIVE_INFINITY;
+            case "Infinity": return Double.POSITIVE_INFINITY;
+            case "-0": return -0.;
+        }
+        return JSON.toJs(val.get("value"));
+    }
 
     private void resume(State state) {
         this.state = state;
@@ -296,7 +359,7 @@ public class SimpleDebugger implements Debugger {
         ws.send(new V8Event("Debugger.paused", map));
     }
     private void pauseException(Context ctx) {
-        state = State.PAUSED_NORMAL;
+        state = State.PAUSED_EXCEPTION;
         var map = new JSONMap()
             .set("callFrames", serializeFrames(ctx))
             .set("reason", "exception");
@@ -322,6 +385,27 @@ public class SimpleDebugger implements Debugger {
         ));
     }
 
+    private RunResult run(Frame codeFrame, String code) {
+        var engine = new Engine();
+        var env = codeFrame.func.environment.fork();
+
+        ObjectValue global = env.global.obj,
+            capture = codeFrame.frame.getCaptureScope(null, enabled),
+            local = codeFrame.frame.getLocalScope(null, enabled);
+
+        capture.setPrototype(null, global);
+        local.setPrototype(null, capture);
+        env.global = new GlobalScope(local);
+
+        var ctx = new Context(engine).pushEnv(env);
+        var awaiter = engine.pushMsg(false, ctx, new Filename("temp", "exec"), code, codeFrame.frame.thisArg, codeFrame.frame.args);
+
+        engine.run(true);
+
+        try { return new RunResult(ctx, awaiter.await(), null); }
+        catch (EngineException e) { return new RunResult(ctx, null, e); }
+    }
+
     @Override public void enable(V8Message msg) {
         enabled = true;
         ws.send(msg.respond());
@@ -342,9 +426,9 @@ public class SimpleDebugger implements Debugger {
         ws.send(msg.respond(new JSONMap().set("scriptSource", idToSource.get(id).source)));
     }
     @Override public void getPossibleBreakpoints(V8Message msg) {
+        var src = idToSource.get(Integer.parseInt(msg.params.map("start").string("scriptId")));
         var start = deserializeLocation(msg.params.get("start"), false);
         var end = msg.params.isMap("end") ? deserializeLocation(msg.params.get("end"), false) : null;
-        var src = idToSource.get(filenameToId.get(start.filename()));
 
         var res = new JSONList();
 
@@ -464,6 +548,101 @@ public class SimpleDebugger implements Debugger {
         }
     }
 
+    @Override public void evaluateOnCallFrame(V8Message msg) {
+        var cfId = Integer.parseInt(msg.params.string("callFrameId"));
+        var expr = msg.params.string("expression");
+        var group = msg.params.string("objectGroup", null);
+
+        var cf = idToFrame.get(cfId);
+        var res = run(cf, expr);
+
+        if (group != null) setObjectGroup(group, res.result);
+
+        ws.send(msg.respond(new JSONMap().set("result", serializeObj(res.ctx, res.result))));
+    }
+
+    @Override public void releaseObjectGroup(V8Message msg) {
+        var group = msg.params.string("objectGroup");
+        releaseGroup(group);
+        ws.send(msg.respond());
+    }
+    @Override public void getProperties(V8Message msg) {
+        var obj = idToObject.get(Integer.parseInt(msg.params.string("objectId")));
+        var own = msg.params.bool("ownProperties") || true;
+        var currOwn = true;
+
+        var res = new JSONList();
+
+        while (obj != null) {
+            var ctx = objectToCtx.get(obj);
+
+            for (var key : obj.keys(true)) {
+                var propDesc = new JSONMap();
+
+                if (obj.properties.containsKey(key)) {
+                    var prop = obj.properties.get(key);
+
+                    propDesc.set("name", Values.toString(ctx, key));
+                    if (prop.getter != null) propDesc.set("get", serializeObj(ctx, prop.getter));
+                    if (prop.setter != null) propDesc.set("set", serializeObj(ctx, prop.setter));
+                    propDesc.set("enumerable", obj.memberEnumerable(key));
+                    propDesc.set("configurable", obj.memberConfigurable(key));
+                    propDesc.set("isOwn", currOwn);
+                    res.add(propDesc);
+                }
+                else {
+                    propDesc.set("name", Values.toString(ctx, key));
+                    propDesc.set("value", serializeObj(ctx, obj.getMember(ctx, key)));
+                    propDesc.set("writable", obj.memberWritable(key));
+                    propDesc.set("enumerable", obj.memberEnumerable(key));
+                    propDesc.set("configurable", obj.memberConfigurable(key));
+                    propDesc.set("isOwn", currOwn);
+                    res.add(propDesc);
+                }
+            }
+
+            obj = obj.getPrototype(ctx);
+
+            var protoDesc = new JSONMap();
+            protoDesc.set("name", "__proto__");
+            protoDesc.set("value", serializeObj(ctx, obj == null ? Values.NULL : obj));
+            protoDesc.set("writable", true);
+            protoDesc.set("enumerable", false);
+            protoDesc.set("configurable", false);
+            protoDesc.set("isOwn", currOwn);
+            res.add(protoDesc);
+
+            currOwn = false;
+            if (own) break;
+        }
+
+        ws.send(msg.respond(new JSONMap().set("result", res)));
+    }
+    @Override public void callFunctionOn(V8Message msg) {
+        var src = msg.params.string("functionDeclaration");
+        var args = msg.params.list("arguments", new JSONList()).stream().map(v -> v.map()).map(this::deserializeArgument).collect(Collectors.toList());
+        var thisArg = idToObject.get(Integer.parseInt(msg.params.string("objectId")));
+        var ctx = objectToCtx.get(thisArg);
+
+        switch (src) {
+            case CHROME_GET_PROP_FUNC: {
+                var path = JSON.parse(new Filename("tmp", "json"), (String)args.get(0)).list();
+                Object res = thisArg;
+                for (var el : path) res = Values.getMember(ctx, res, JSON.toJs(el));
+                ws.send(msg.respond(new JSONMap().set("result", serializeObj(ctx, res))));
+                return;
+            }
+            default:
+                ws.send(new V8Error("A non well-known function was used with callFunctionOn."));
+                break;
+        }
+    }
+
+    @Override
+    public void runtimeEnable(V8Message msg) {
+        ws.send(msg.respond());
+    }
+
     @Override public void onSource(Filename filename, String source, TreeSet<Location> locations) {
         int id = nextId();
         var src = new Source(id, filename, source, locations);
@@ -488,6 +667,9 @@ public class SimpleDebugger implements Debugger {
 
         updateFrames(ctx);
         var frame = codeFrameToFrame.get(cf);
+
+        if (!frame.debugData) return false;
+
         if (instruction.location != null) frame.updateLoc(instruction.location);
         var loc = frame.location;
         var isBreakpointable = loc != null && (
@@ -501,15 +683,12 @@ public class SimpleDebugger implements Debugger {
             pauseException(ctx);
         }
         else if (isBreakpointable && locToBreakpoint.containsKey(loc)) {
-            pauseDebug(ctx, locToBreakpoint.get(loc));
+            var bp = locToBreakpoint.get(loc);
-        }
+            var ok = bp.condition == null ? true : Values.toBoolean(run(currFrame, bp.condition));
-        else if (isBreakpointable && tmpBreakpts.contains(loc)) {
+            if (ok) pauseDebug(ctx, locToBreakpoint.get(loc));
-            pauseDebug(ctx, null);
-            tmpBreakpts.remove(loc);
-        }
-        else if (instruction.type == Type.NOP && instruction.match("debug")) {
-            pauseDebug(ctx, null);
         }
+        else if (isBreakpointable && tmpBreakpts.remove(loc)) pauseDebug(ctx, null);
+        else if (instruction.type == Type.NOP && instruction.match("debug")) pauseDebug(ctx, null);
 
         while (enabled) {
             switch (state) {
@@ -527,12 +706,17 @@ public class SimpleDebugger implements Debugger {
                     else return false;
                     break;
                 case STEPPING_OVER:
-                    if (
+                    if (stepOutFrame.frame == frame.frame) {
-                        stepOutFrame == frame && (
+                        if (returnVal != Runners.NO_RETURN) {
+                            state = State.STEPPING_OUT;
+                            return false;
+                        }
+                        else if (isBreakpointable && (
                             !loc.filename().equals(prevLocation.filename()) ||
                             loc.line() != prevLocation.line()
-                        )
+                        )) pauseDebug(ctx, null);
-                    ) pauseDebug(ctx, null);
+                        else return false;
+                    }
                     else return false;
                     break;
             }
@@ -544,14 +728,12 @@ public class SimpleDebugger implements Debugger {
     @Override public void onFramePop(Context ctx, CodeFrame frame) {
         updateFrames(ctx);
 
-        try {
+        try { idToFrame.remove(codeFrameToFrame.remove(frame).id); }
-            idToFrame.remove(codeFrameToFrame.remove(frame).id);
-        }
         catch (NullPointerException e) { }
 
         if (StackData.frames(ctx).size() == 0) resume(State.RESUMED);
         else if (stepOutFrame != null && stepOutFrame.frame == frame &&
-            (state == State.STEPPING_OUT || state == State.STEPPING_IN || state == State.STEPPING_OVER)
+            (state == State.STEPPING_OUT || state == State.STEPPING_IN)
         ) {
             pauseDebug(ctx, null);
             updateNotifier.await();

src/me/topchetoeu/jscript/engine/debug/WebSocket.java

@@ -7,7 +7,6 @@ import java.io.OutputStream;
 import java.net.Socket;
 
 import me.topchetoeu.jscript.engine.debug.WebSocketMessage.Type;
-import me.topchetoeu.jscript.exceptions.UncheckedException;
 import me.topchetoeu.jscript.exceptions.UncheckedIOException;
 
 public class WebSocket implements AutoCloseable {

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

@@ -10,6 +10,8 @@ import me.topchetoeu.jscript.engine.scope.LocalScope;
 import me.topchetoeu.jscript.engine.scope.ValueVariable;
 import me.topchetoeu.jscript.engine.values.ArrayValue;
 import me.topchetoeu.jscript.engine.values.CodeFunction;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.engine.values.ScopeValue;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.exceptions.InterruptException;
@@ -56,6 +58,33 @@ public class CodeFrame {
     public boolean jumpFlag = false;
     private Location prevLoc = null;
 
+    public ObjectValue getLocalScope(Context ctx, boolean props) {
+        var names = new String[scope.locals.length];
+
+        for (int i = 0; i < scope.locals.length; i++) {
+            var name = "local_" + (i - 2);
+
+            if (i == 0) name = "this";
+            else if (i == 1) name = "arguments";
+            else if (i < function.localNames.length) name = function.localNames[i];
+
+            names[i] = name;
+        }
+
+        return new ScopeValue(scope.locals, names);
+    }
+    public ObjectValue getCaptureScope(Context ctx, boolean props) {
+        var names = new String[scope.captures.length];
+
+        for (int i = 0; i < scope.captures.length; i++) {
+            var name = "capture_" + (i - 2);
+            if (i < function.captureNames.length) name = function.captureNames[i];
+            names[i] = name;
+        }
+
+        return new ScopeValue(scope.captures, names);
+    }
+
     public void addTry(int n, int catchN, int finallyN) {
         var res = new TryCtx(codePtr + 1, n, catchN, finallyN);
 
@@ -144,7 +173,7 @@ public class CodeFrame {
                     }
                     else if (returnValue != Runners.NO_RETURN) {
                         if (tryCtx.hasFinally) {
-                            tryCtx.retVal = error;
+                            tryCtx.retVal = returnValue;
                             newState = TryCtx.STATE_FINALLY_RETURNED;
                         }
                         break;
@@ -215,6 +244,7 @@ public class CodeFrame {
                 case TryCtx.STATE_CATCH:
                     scope.catchVars.add(new ValueVariable(false, tryCtx.err.value));
                     codePtr = tryCtx.catchStart;
+                    if (debugger != null) debugger.onInstruction(ctx, this, function.body[codePtr], null, error, true);
                     break;
                 default:
                     codePtr = tryCtx.finallyStart;

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

@@ -301,15 +301,6 @@ public class Runners {
         return NO_RETURN;
     }
     public static Object execNop(Context ctx, Instruction instr, CodeFrame frame) {
-        if (instr.is(0, "dbg_names")) {
-            var names = new String[instr.params.length - 1];
-            for (var i = 0; i < instr.params.length - 1; i++) {
-                if (!(instr.params[i + 1] instanceof String)) throw EngineException.ofSyntax("NOP dbg_names instruction must specify only string parameters.");
-                names[i] = (String)instr.params[i + 1];
-            }
-            frame.scope.setNames(names);
-        }
-
         frame.codePtr++;
         return NO_RETURN;
     }

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

@@ -2,12 +2,7 @@ package me.topchetoeu.jscript.engine.scope;
 
 import java.util.ArrayList;
 
-import me.topchetoeu.jscript.engine.Context;
-import me.topchetoeu.jscript.engine.values.NativeFunction;
-import me.topchetoeu.jscript.engine.values.ObjectValue;
-
 public class LocalScope {
-    private String[] names;
     public final ValueVariable[] captures;
     public final ValueVariable[] locals;
     public final ArrayList<ValueVariable> catchVars = new ArrayList<>();
@@ -19,70 +14,11 @@ public class LocalScope {
         else return captures[~i];
     }
 
-    public String[] getCaptureNames() {
-        var res = new String[captures.length];
-
-        for (int i = 0; i < captures.length; i++) {
-            if (names == null || i >= names.length) res[i] = "capture_" + (i);
-            else res[i] = names[i];
-        }
-
-        return res;
-    }
-    public String[] getLocalNames() {
-        var res = new String[locals.length];
-
-        for (int i = captures.length, j = 0; i < locals.length; i++, j++) {
-            if (names == null || i >= names.length) {
-                if (j == 0) res[j] = "this";
-                else if (j == 1) res[j] = "arguments";
-                else res[i] = "local_" + (j - 2);
-            }
-            else res[i] = names[i];
-        }
-
-        return res;
-    }
-    public void setNames(String[] names) {
-        this.names = names;
-    }
 
     public int size() {
         return captures.length + locals.length;
     }
 
-    public void applyToObject(Context ctx, ObjectValue locals, ObjectValue captures, boolean props) {
-        var localNames = getLocalNames();
-        var captureNames = getCaptureNames();
-
-        for (var i = 0; i < this.locals.length; i++) {
-            var name = localNames[i];
-            var _i = i;
-
-            if (props) locals.defineProperty(ctx, name,
-                new NativeFunction(name, (_ctx, thisArg, args) -> this.locals[_i].get(_ctx)),
-                this.locals[i].readonly ? null :
-                    new NativeFunction(name, (_ctx, thisArg, args) -> { this.locals[_i].set(_ctx, args.length < 1 ? null : args[0]); return null; }),
-                true, true
-            );
-            else locals.defineProperty(ctx, name, this.locals[i].get(ctx));
-        }
-        for (var i = 0; i < this.captures.length; i++) {
-            var name = captureNames[i];
-            var _i = i;
-
-            if (props) captures.defineProperty(ctx, name,
-                new NativeFunction(name, (_ctx, thisArg, args) -> this.captures[_i].get(_ctx)),
-                this.captures[i].readonly ? null :
-                    new NativeFunction(name, (_ctx, thisArg, args) -> { this.captures[_i].set(_ctx, args.length < 1 ? null : args[0]); return null; }),
-                true, true
-            );
-            else captures.defineProperty(ctx, name, this.captures[i].get(ctx));
-        }
-
-        captures.setPrototype(ctx, locals);
-    }
-
     public LocalScope(int n, ValueVariable[] captures) {
         locals = new ValueVariable[n];
         this.captures = captures;

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

@@ -11,6 +11,9 @@ public class LocalScopeRecord implements ScopeRecord {
     private final ArrayList<String> captures = new ArrayList<>();
     private final ArrayList<String> locals = new ArrayList<>();
 
+    public String[] captures() {
+        return captures.toArray(String[]::new);
+    }
     public String[] locals() {
         return locals.toArray(String[]::new);
     }

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

@@ -1,6 +1,7 @@
 package me.topchetoeu.jscript.engine.values;
 
 import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.compilation.FunctionBody;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.Context;
 import me.topchetoeu.jscript.engine.Environment;
@@ -13,6 +14,7 @@ public class CodeFunction extends FunctionValue {
     public final int localsN;
     public final int length;
     public final Instruction[] body;
+    public final String[] captureNames, localNames;
     public final ValueVariable[] captures;
     public Environment environment;
 
@@ -45,12 +47,14 @@ public class CodeFunction extends FunctionValue {
         }
     }
 
-    public CodeFunction(Environment environment, String name, int localsN, int length, ValueVariable[] captures, Instruction[] body) {
+    public CodeFunction(Environment environment, String name, int localsN, int length, ValueVariable[] captures, FunctionBody body) {
         super(name, length);
         this.captures = captures;
+        this.captureNames = body.captureNames;
+        this.localNames = body.localNames;
         this.environment = environment;
         this.localsN = localsN;
         this.length = length;
-        this.body = body;
+        this.body = body.instructions;
     }
 }

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

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

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

@@ -1,9 +1,15 @@
 package me.topchetoeu.jscript.json;
 
+import java.util.HashSet;
 import java.util.List;
 import java.util.stream.Collectors;
 
 import me.topchetoeu.jscript.Filename;
+import me.topchetoeu.jscript.engine.Context;
+import me.topchetoeu.jscript.engine.values.ArrayValue;
+import me.topchetoeu.jscript.engine.values.ObjectValue;
+import me.topchetoeu.jscript.engine.values.Values;
+import me.topchetoeu.jscript.exceptions.EngineException;
 import me.topchetoeu.jscript.exceptions.SyntaxException;
 import me.topchetoeu.jscript.parsing.Operator;
 import me.topchetoeu.jscript.parsing.ParseRes;
@@ -11,6 +17,63 @@ import me.topchetoeu.jscript.parsing.Parsing;
 import me.topchetoeu.jscript.parsing.Token;
 
 public class JSON {
+    public static Object toJs(JSONElement val) {
+        if (val.isBoolean()) return val.bool();
+        if (val.isString()) return val.string();
+        if (val.isNumber()) return val.number();
+        if (val.isList()) return ArrayValue.of(null, val.list().stream().map(JSON::toJs).collect(Collectors.toList()));
+        if (val.isMap()) {
+            var res = new ObjectValue();
+            for (var el : val.map().entrySet()) {
+                res.defineProperty(null, el.getKey(), toJs(el.getValue()));
+            }
+            return res;
+        }
+        if (val.isNull()) return Values.NULL;
+        return null;
+    }
+    private static JSONElement fromJs(Context ctx, Object val, HashSet<Object> prev) {
+        if (val instanceof Boolean) return JSONElement.bool((boolean)val);
+        if (val instanceof Number) return JSONElement.number(((Number)val).doubleValue());
+        if (val instanceof String) return JSONElement.string((String)val);
+        if (val == Values.NULL) return JSONElement.NULL;
+        if (val instanceof ObjectValue) {
+            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
+            prev.add(val);
+
+            var res = new JSONMap();
+
+            for (var el : ((ObjectValue)val).keys(false)) {
+                var jsonEl = fromJs(ctx, ((ObjectValue)val).getMember(ctx, el), prev);
+                if (jsonEl == null) continue;
+                if (el instanceof String || el instanceof Number) res.put(el.toString(), jsonEl);
+            }
+
+            prev.remove(val);
+            return JSONElement.of(res);
+        }
+        if (val instanceof ArrayValue) {
+            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
+            prev.add(val);
+
+            var res = new JSONList();
+
+            for (var el : ((ArrayValue)val).toArray()) {
+                var jsonEl = fromJs(ctx, el, prev);
+                if (jsonEl == null) jsonEl = JSONElement.NULL;
+                res.add(jsonEl);
+            }
+
+            prev.remove(val);
+            return JSONElement.of(res);
+        }
+        if (val == null) return null;
+        return null;
+    }
+    public static JSONElement fromJs(Context ctx, Object val) {
+        return fromJs(ctx, val, new HashSet<>());
+    }
+
     public static ParseRes<String> parseIdentifier(List<Token> tokens, int i) {
         return Parsing.parseIdentifier(tokens, i);
     }

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

@@ -10,6 +10,9 @@ public class JSONList extends ArrayList<JSONElement> {
     public JSONList(JSONElement ...els) {
         super(List.of(els));
     }
+    public JSONList(Collection<JSONElement> els) {
+        super(els);
+    }
 
     public JSONList addNull() { this.add(JSONElement.NULL); return this; }
     public JSONList add(String val) { this.add(JSONElement.of(val)); return this; }

src/me/topchetoeu/jscript/lib/JSONLib.java

@@ -1,84 +1,22 @@
 package me.topchetoeu.jscript.lib;
 
-import java.util.HashSet;
-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.interop.Native;
-import me.topchetoeu.jscript.json.JSONElement;
+import me.topchetoeu.jscript.json.JSON;
-import me.topchetoeu.jscript.json.JSONList;
-import me.topchetoeu.jscript.json.JSONMap;
 
 public class JSONLib {
-    private static Object toJS(JSONElement val) {
-        if (val.isBoolean()) return val.bool();
-        if (val.isString()) return val.string();
-        if (val.isNumber()) return val.number();
-        if (val.isList()) return ArrayValue.of(null, val.list().stream().map(JSONLib::toJS).collect(Collectors.toList()));
-        if (val.isMap()) {
-            var res = new ObjectValue();
-            for (var el : val.map().entrySet()) {
-                res.defineProperty(null, el.getKey(), toJS(el.getValue()));
-            }
-            return res;
-        }
-        if (val.isNull()) return Values.NULL;
-        return null;
-    }
-    private static JSONElement toJSON(Context ctx, Object val, HashSet<Object> prev) {
-        if (val instanceof Boolean) return JSONElement.bool((boolean)val);
-        if (val instanceof Number) return JSONElement.number(((Number)val).doubleValue());
-        if (val instanceof String) return JSONElement.string((String)val);
-        if (val == Values.NULL) return JSONElement.NULL;
-        if (val instanceof ObjectValue) {
-            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
-            prev.add(val);
-
-            var res = new JSONMap();
-
-            for (var el : ((ObjectValue)val).keys(false)) {
-                var jsonEl = toJSON(ctx, ((ObjectValue)val).getMember(ctx, el), prev);
-                if (jsonEl == null) continue;
-                if (el instanceof String || el instanceof Number) res.put(el.toString(), jsonEl);
-            }
-
-            prev.remove(val);
-            return JSONElement.of(res);
-        }
-        if (val instanceof ArrayValue) {
-            if (prev.contains(val)) throw new EngineException("Circular dependency in JSON.");
-            prev.add(val);
-
-            var res = new JSONList();
-
-            for (var el : ((ArrayValue)val).toArray()) {
-                var jsonEl = toJSON(ctx, el, prev);
-                if (jsonEl == null) jsonEl = JSONElement.NULL;
-                res.add(jsonEl);
-            }
-
-            prev.remove(val);
-            return JSONElement.of(res);
-        }
-        if (val == null) return null;
-        return null;
-    }
-
     @Native
     public static Object parse(Context ctx, String val) {
         try {
-            return toJS(me.topchetoeu.jscript.json.JSON.parse(new Filename("jscript", "json"), val));
+            return JSON.toJs(JSON.parse(new Filename("jscript", "json"), val));
         }
         catch (SyntaxException e) { throw EngineException.ofSyntax(e.msg); }
     }
     @Native
     public static String stringify(Context ctx, Object val) {
-        return me.topchetoeu.jscript.json.JSON.stringify(toJSON(ctx, val, new HashSet<>()));
+        return me.topchetoeu.jscript.json.JSON.stringify(JSON.fromJs(ctx, val));
     }
 }

src/me/topchetoeu/jscript/parsing/Parsing.java

@@ -1367,6 +1367,7 @@ public class Parsing {
         }
 
         while (true) {
+            var nameLoc = getLoc(filename, tokens, i + n);
             var nameRes = parseIdentifier(tokens, i + n++);
             if (!nameRes.isSuccess()) return ParseRes.error(loc, "Expected a variable name.");
 
@@ -1384,7 +1385,7 @@ public class Parsing {
                 val = valRes.result;
             }
 
-            res.add(new Pair(nameRes.result, val));
+            res.add(new Pair(nameRes.result, val, nameLoc));
             
             if (isOperator(tokens, i + n, Operator.COMMA)) {
                 n++;
@@ -1512,7 +1513,7 @@ public class Parsing {
             statements.add(res.result);
         }
 
-        return ParseRes.res(new CompoundStatement(loc, statements.toArray(Statement[]::new)), n);
+        return ParseRes.res(new CompoundStatement(loc, statements.toArray(Statement[]::new)).setEnd(getLoc(filename, tokens, i + n - 1)), n);
     }
     public static ParseRes<String> parseLabel(List<Token> tokens, int i) {
         int n = 0;
@@ -1876,7 +1877,7 @@ public class Parsing {
         return list.toArray(Statement[]::new);
     }
 
-    public static CodeFunction compile(HashMap<Long, Instruction[]> funcs, TreeSet<Location> breakpoints, Environment environment, Statement ...statements) {
+    public static CodeFunction compile(HashMap<Long, FunctionBody> funcs, TreeSet<Location> breakpoints, Environment environment, Statement ...statements) {
         var target = environment.global.globalChild();
         var subscope = target.child();
         var res = new CompileTarget(funcs, breakpoints);
@@ -1903,14 +1904,14 @@ public class Parsing {
         }
         else res.add(Instruction.ret());
 
-        return new CodeFunction(environment, "", subscope.localsCount(), 0, new ValueVariable[0], res.array());
+        return new CodeFunction(environment, "", subscope.localsCount(), 0, new ValueVariable[0], new FunctionBody(res.array(), subscope.captures(), subscope.locals()));
     }
-    public static CodeFunction compile(HashMap<Long, Instruction[]> funcs, TreeSet<Location> breakpoints, Environment environment, Filename filename, String raw) {
+    public static CodeFunction compile(HashMap<Long, FunctionBody> funcs, TreeSet<Location> breakpoints, Environment environment, Filename filename, String raw) {
         try {
             return compile(funcs, breakpoints, environment, parse(filename, raw));
         }
         catch (SyntaxException e) {
-            return new CodeFunction(environment, null, 2, 0, new ValueVariable[0], new Instruction[] { Instruction.throwSyntax(e) });
+            return new CodeFunction(environment, null, 2, 0, new ValueVariable[0], new FunctionBody(new Instruction[] { Instruction.throwSyntax(e).locate(e.loc) }));
         }
     }
 }