clean up member logic

src/main/java/me/topchetoeu/jscript/runtime/Frame.java

@@ -1,8 +1,6 @@
 package me.topchetoeu.jscript.runtime;
 
 import java.util.Arrays;
-import java.util.LinkedHashSet;
-import java.util.Set;
 import java.util.Stack;
 
 import me.topchetoeu.jscript.common.Instruction;
@@ -11,11 +9,9 @@ import me.topchetoeu.jscript.common.environment.Key;
 import me.topchetoeu.jscript.runtime.debug.DebugContext;
 import me.topchetoeu.jscript.runtime.exceptions.EngineException;
 import me.topchetoeu.jscript.runtime.exceptions.InterruptException;
-import me.topchetoeu.jscript.runtime.values.KeyCache;
-import me.topchetoeu.jscript.runtime.values.Member;
 import me.topchetoeu.jscript.runtime.values.Value;
-import me.topchetoeu.jscript.runtime.values.Member.FieldMember;
 import me.topchetoeu.jscript.runtime.values.functions.CodeFunction;
+import me.topchetoeu.jscript.runtime.values.objects.ArrayLikeValue;
 import me.topchetoeu.jscript.runtime.values.objects.ObjectValue;
 
 public final class Frame {
@@ -385,31 +381,39 @@ public final class Frame {
      * Gets an array proxy of the local locals
      */
     public ObjectValue getValStackScope() {
-        return new ObjectValue() {
+        return new ArrayLikeValue() {
-            @Override public Member getOwnMember(Environment env, KeyCache key) {
+            @Override public Value get(int i) { return stack[i]; }
-                var res = super.getOwnMember(env, key);
+            @Override public void set(int i, Value val) { stack[i] = val; }
-                if (res != null) return res;
+            @Override public boolean has(int i) { return i >= 0 && i < size(); }
+            @Override public void remove(int i) { }
 
-                var num = key.toNumber(env);
+            @Override public int size() { return stackPtr; }
-                var i = key.toInt(env);
+            @Override public boolean setSize(int val) { return false; }
 
-                if (num != i || i < 0 || i >= stackPtr) return null;
+            // @Override public Member getOwnMember(Environment env, KeyCache key) {
-                else return new FieldMember(false, true, true) {
+            //     var res = super.getOwnMember(env, key);
-                    @Override public Value get(Environment env, Value self) { return stack[i]; }
+            //     if (res != null) return res;
-                    @Override public boolean set(Environment env, Value val, Value self) {
-                        stack[i] = val;
-                        return true;
-                    }
-                };
-            }
-            @Override public Set<String> getOwnMembers(Environment env, boolean onlyEnumerable) {
-                var res = new LinkedHashSet<String>();
-                res.addAll(super.getOwnMembers(env, onlyEnumerable));
 
-                for (var i = 0; i < stackPtr; i++) res.add(i + "");
+            //     var num = key.toNumber(env);
+            //     var i = key.toInt(env);
 
-                return res;
+            //     if (num != i || i < 0 || i >= stackPtr) return null;
-            }
+            //     else return new FieldMember(this, false, true, true) {
+            //         @Override public Value get(Environment env, Value self) { return stack[i]; }
+            //         @Override public boolean set(Environment env, Value val, Value self) {
+            //             stack[i] = val;
+            //             return true;
+            //         }
+            //     };
+            // }
+            // @Override public Set<String> getOwnMembers(Environment env, boolean onlyEnumerable) {
+            //     var res = new LinkedHashSet<String>();
+            //     res.addAll(super.getOwnMembers(env, onlyEnumerable));
+
+            //     for (var i = 0; i < stackPtr; i++) res.add(i + "");
+
+            //     return res;
+            // }
         };
     }
 

src/main/java/me/topchetoeu/jscript/runtime/InstructionRunner.java

@@ -73,7 +73,7 @@ public class InstructionRunner {
         else if (setterVal instanceof FunctionValue) setter = (FunctionValue)setterVal;
         else throw EngineException.ofType("Setter must be a function or undefined.");
 
-        obj.defineOwnMember(env, key, new PropertyMember(getter, setter, true, true));
+        obj.defineOwnMember(env, key, new PropertyMember(obj, getter, setter, true, true));
 
         frame.push(obj);
         frame.codePtr++;

src/main/java/me/topchetoeu/jscript/runtime/JSONConverter.java

@@ -8,7 +8,6 @@ import me.topchetoeu.jscript.common.json.JSONElement;
 import me.topchetoeu.jscript.common.json.JSONList;
 import me.topchetoeu.jscript.common.json.JSONMap;
 import me.topchetoeu.jscript.runtime.exceptions.EngineException;
-import me.topchetoeu.jscript.runtime.values.Member.FieldMember;
 import me.topchetoeu.jscript.runtime.values.Value;
 import me.topchetoeu.jscript.runtime.values.objects.ArrayValue;
 import me.topchetoeu.jscript.runtime.values.objects.ObjectValue;
@@ -27,7 +26,7 @@ public class JSONConverter {
             var res = new ObjectValue();
     
             for (var el : val.map().entrySet()) {
-                res.defineOwnMember(null, el.getKey(), FieldMember.of(toJs(el.getValue())));
+                res.defineOwnMember(null, el.getKey(), toJs(el.getValue()));
             }
     
             return res;

src/main/java/me/topchetoeu/jscript/runtime/SimpleRepl.java

@@ -171,9 +171,7 @@ public class SimpleRepl {
             var configurable = args.get(4).toBoolean();
             var value = args.get(5);
 
-            obj.defineOwnMember(args.env, key, FieldMember.of(value, enumerable, configurable, writable));
+            return BoolValue.of(obj.defineOwnMember(args.env, key, FieldMember.of(obj, value, configurable, enumerable, writable)));
-
-            return Value.UNDEFINED;
         }));
         res.defineOwnMember(env, "defineProperty", new NativeFunction(args -> {
             var obj = (ObjectValue)args.get(0);
@@ -183,9 +181,7 @@ public class SimpleRepl {
             var getter = args.get(4) instanceof VoidValue ? null : (FunctionValue)args.get(4);
             var setter = args.get(5) instanceof VoidValue ? null : (FunctionValue)args.get(5);
 
-            obj.defineOwnMember(args.env, key, new PropertyMember(getter, setter, configurable, enumerable));
+            return BoolValue.of(obj.defineOwnMember(args.env, key, new PropertyMember(obj, getter, setter, configurable, enumerable)));
-
-            return Value.UNDEFINED;
         }));
         res.defineOwnMember(env, "getPrototype", new NativeFunction(args -> {
             return args.get(0).getPrototype(env);

src/main/java/me/topchetoeu/jscript/runtime/exceptions/EngineException.java

@@ -6,7 +6,6 @@ import java.util.List;
 import me.topchetoeu.jscript.common.environment.Environment;
 import me.topchetoeu.jscript.common.parsing.Location;
 import me.topchetoeu.jscript.runtime.values.Value;
-import me.topchetoeu.jscript.runtime.values.Member.FieldMember;
 import me.topchetoeu.jscript.runtime.values.objects.ObjectValue;
 import me.topchetoeu.jscript.runtime.values.objects.ObjectValue.PrototypeProvider;
 import me.topchetoeu.jscript.runtime.values.primitives.StringValue;
@@ -98,8 +97,8 @@ public class EngineException extends RuntimeException {
 
         if (msg == null) msg = "";
 
-        if (name != null) res.defineOwnMember(Environment.empty(), "name", FieldMember.of(new StringValue(name)));
+        if (name != null) res.defineOwnMember(Environment.empty(), "name", new StringValue(name));
-        res.defineOwnMember(Environment.empty(), "message", FieldMember.of(new StringValue(msg)));
+        res.defineOwnMember(Environment.empty(), "message", new StringValue(msg));
         return res;
     }
 

src/main/java/me/topchetoeu/jscript/runtime/values/Member.java

@@ -7,10 +7,11 @@ import me.topchetoeu.jscript.runtime.values.primitives.BoolValue;
 
 public interface Member {
     public static final class PropertyMember implements Member {
-        public final FunctionValue getter;
+        public final Value self;
-        public final FunctionValue setter;
+        public FunctionValue getter;
-        public final boolean configurable;
+        public FunctionValue setter;
-        public final boolean enumerable;
+        public boolean configurable;
+        public boolean enumerable;
 
         @Override public Value get(Environment env, Value self) {
             if (getter != null) return getter.call(env, false, "", self);
@@ -22,36 +23,51 @@ public interface Member {
             return true;
         }
 
-        @Override public boolean configurable() { return configurable; }
+        @Override public boolean configurable() { return configurable && self.getState().configurable; }
         @Override public boolean enumerable() { return enumerable; }
 
-        @Override public boolean configure(Environment env, Member newMember, Value self) {
+        @Override public boolean redefine(Environment env, Member newMember, Value self) {
-            if (!(newMember instanceof PropertyMember)) return false;
+            // If the given member isn't a property, we can't redefine
-            var prop = (PropertyMember)newMember;
+            if (!(newMember instanceof PropertyMember prop)) return false;
 
-            if (prop.configurable != configurable) return false;
+            if (configurable()) {
+                // We will overlay the getters and setters of the new member
+                enumerable = prop.enumerable;
+                configurable = prop.configurable;
+
+                if (prop.getter != null) getter = prop.getter;
+                if (prop.setter != null) setter = prop.setter;
+
+                return true;
+            }
+            else {
+                // We will pretend that a redefinition has occurred if the two members match exactly
+                if (prop.configurable() != configurable()) return false;
                 if (prop.enumerable != enumerable) return false;
+                if (prop.getter != getter || prop.setter != setter) return false;
 
-            if (prop.getter == getter) return true;
+                return true;
-            if (prop.setter == setter) return true;
+            }
-            return false;
         }
 
         @Override public ObjectValue descriptor(Environment env, Value self) {
             var res = new ObjectValue();
 
-            if (getter == null) res.defineOwnMember(env, "getter", FieldMember.of(Value.UNDEFINED));
+            // Don't touch the ordering, as it's emulating V8
-            else res.defineOwnMember(env, "getter", FieldMember.of(getter));
 
-            if (setter == null) res.defineOwnMember(env, "setter", FieldMember.of(Value.UNDEFINED));
+            if (getter == null) res.defineOwnMember(env, "getter", Value.UNDEFINED);
-            else res.defineOwnMember(env, "setter", FieldMember.of(setter));
+            else res.defineOwnMember(env, "getter", getter);
 
-            res.defineOwnMember(env, "enumerable", FieldMember.of(BoolValue.of(enumerable)));
+            if (setter == null) res.defineOwnMember(env, "setter", Value.UNDEFINED);
-            res.defineOwnMember(env, "configurable", FieldMember.of(BoolValue.of(configurable)));
+            else res.defineOwnMember(env, "setter", setter);
+
+            res.defineOwnMember(env, "enumerable", BoolValue.of(enumerable));
+            res.defineOwnMember(env, "configurable", BoolValue.of(configurable));
             return res;
         }
 
-        public PropertyMember(FunctionValue getter, FunctionValue setter, boolean configurable, boolean enumerable) {
+        public PropertyMember(Value self, FunctionValue getter, FunctionValue setter, boolean configurable, boolean enumerable) {
+            this.self = self;
             this.getter = getter;
             this.setter = setter;
             this.configurable = configurable;
@@ -69,60 +85,87 @@ public interface Member {
                 value = val;
                 return true;
             }
-            public SimpleFieldMember(Value value, boolean configurable, boolean enumerable, boolean writable) {
+            public SimpleFieldMember(Value self, Value value, boolean configurable, boolean enumerable, boolean writable) {
-                super(configurable, enumerable, writable);
+                super(self, configurable, enumerable, writable);
                 this.value = value;
             }
         }
 
+        public final Value self;
         public boolean configurable;
         public boolean enumerable;
         public boolean writable;
 
-        @Override public final boolean configurable() { return configurable; }
+        @Override public final boolean configurable() { return configurable && self.getState().configurable; }
         @Override public final boolean enumerable() { return enumerable; }
-        @Override public final boolean configure(Environment env, Member newMember, Value self) {
+        public final boolean writable() { return writable && self.getState().writable; }
-            if (!(newMember instanceof FieldMember)) return false;
-            var field = (FieldMember)newMember;
 
-            if (field.configurable != configurable) return false;
+        @Override public final boolean redefine(Environment env, Member newMember, Value self) {
-            if (field.enumerable != enumerable) return false;
+            // If the given member isn't a field, we can't redefine
-            if (!writable) return field.get(env, self).equals(get(env, self));
+            if (!(newMember instanceof FieldMember field)) return false;
 
-            set(env, field.get(env, self), self);
+            if (configurable()) {
-            writable = field.writable;
+                configurable = field.configurable;
+                enumerable = field.enumerable;
+                writable = field.enumerable;
+
+                // We will try to set a new value. However, the underlying field might be immutably readonly
+                // In such case, we will silently fail, since this is not covered by the specification
+                if (!set(env, field.get(env, self), self)) writable = false;
                 return true;
             }
+            else {
+                // New field settings must be an exact match
+                if (configurable() != field.configurable()) return false;
+                if (enumerable() != field.enumerable()) return false;
+
+                if (!writable()) {
+                    // If the field isn't writable, the redefinition should be an exact match
+                    if (field.writable()) return false;
+                    if (field.get(env, self).equals(this.get(env, self))) return false;
+
+                    return true;
+                }
+                else {
+                    // Writable non-configurable fields may be made readonly or their values may be changed
+                    writable = field.writable;
+
+                    if (!set(env, field.get(env, self), self)) writable = false;
+                    return true;
+                }
+            }
+        }
 
         @Override public ObjectValue descriptor(Environment env, Value self) {
             var res = new ObjectValue();
-            res.defineOwnMember(env, "value", FieldMember.of(get(env, self)));
+            res.defineOwnMember(env, "value", get(env, self));
-            res.defineOwnMember(env, "writable", FieldMember.of(BoolValue.of(writable)));
+            res.defineOwnMember(env, "writable", BoolValue.of(writable));
-            res.defineOwnMember(env, "enumerable", FieldMember.of(BoolValue.of(enumerable)));
+            res.defineOwnMember(env, "enumerable", BoolValue.of(enumerable));
-            res.defineOwnMember(env, "configurable", FieldMember.of(BoolValue.of(configurable)));
+            res.defineOwnMember(env, "configurable", BoolValue.of(configurable));
             return res;
         }
 
-        public FieldMember(boolean configurable, boolean enumerable, boolean writable) {
+        public FieldMember(Value self, boolean configurable, boolean enumerable, boolean writable) {
+            this.self = self;
             this.configurable = configurable;
             this.enumerable = enumerable;
             this.writable = writable;
         }
 
-        public static FieldMember of(Value value) {
+        public static FieldMember of(Value self, Value value) {
-            return new SimpleFieldMember(value, true, true, true);
+            return new SimpleFieldMember(self, value, true, true, true);
         }
-        public static FieldMember of(Value value, boolean writable) {
+        public static FieldMember of(Value self, Value value, boolean writable) {
-            return new SimpleFieldMember(value, true, true, writable);
+            return new SimpleFieldMember(self, value, true, true, writable);
         }
-        public static FieldMember of(Value value, boolean configurable, boolean enumerable, boolean writable) {
+        public static FieldMember of(Value self, Value value, boolean configurable, boolean enumerable, boolean writable) {
-            return new SimpleFieldMember(value, configurable, enumerable, writable);
+            return new SimpleFieldMember(self, value, configurable, enumerable, writable);
         }
     }
 
     public boolean configurable();
     public boolean enumerable();
-    public boolean configure(Environment env, Member newMember, Value self);
+    public boolean redefine(Environment env, Member newMember, Value self);
     public ObjectValue descriptor(Environment env, Value self);
 
     public Value get(Environment env, Value self);

src/main/java/me/topchetoeu/jscript/runtime/values/Value.java

@@ -20,6 +20,7 @@ import me.topchetoeu.jscript.runtime.debug.DebugContext;
 import me.topchetoeu.jscript.runtime.exceptions.EngineException;
 import me.topchetoeu.jscript.runtime.exceptions.SyntaxException;
 import me.topchetoeu.jscript.runtime.values.Member.FieldMember;
+import me.topchetoeu.jscript.runtime.values.Member.PropertyMember;
 import me.topchetoeu.jscript.runtime.values.functions.FunctionValue;
 import me.topchetoeu.jscript.runtime.values.functions.NativeFunction;
 import me.topchetoeu.jscript.runtime.values.objects.ArrayValue;
@@ -31,21 +32,21 @@ import me.topchetoeu.jscript.runtime.values.primitives.SymbolValue;
 import me.topchetoeu.jscript.runtime.values.primitives.VoidValue;
 
 public abstract class Value {
-    public static enum CompareResult {
+    public static enum State {
-        NOT_EQUAL,
+        NORMAL(true, true, true),
-        EQUAL,
+        NON_EXTENDABLE(false, true, true),
-        LESS,
+        SEALED(false, false, true),
-        GREATER;
+        FROZEN(false, false, false);
 
-        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) {
+        public final boolean extendable;
-            if (cmp < 0) return LESS;
+        public final boolean configurable;
-            if (cmp > 0) return GREATER;
+        public final boolean writable;
-            return EQUAL;
+
+        private State(boolean extendable, boolean configurable, boolean writable) {
+            this.extendable = extendable;
+            this.writable = writable;
+            this.configurable = configurable;
         }
     }
 
@@ -132,6 +133,12 @@ public abstract class Value {
     public abstract ObjectValue getPrototype(Environment env);
     public abstract boolean setPrototype(Environment env, ObjectValue val);
 
+    public abstract State getState();
+
+    public abstract void preventExtensions();
+    public abstract void seal();
+    public abstract void freeze();
+
     public final Member getOwnMember(Environment env, Value key) {
         return getOwnMember(env, new KeyCache(key));
     }
@@ -159,19 +166,19 @@ public abstract class Value {
     }
 
     public final boolean defineOwnMember(Environment env, KeyCache key, Value val) {
-        return defineOwnMember(env, key, FieldMember.of(val));
+        return defineOwnMember(env, key, FieldMember.of(this, val));
     }
     public final boolean defineOwnMember(Environment env, Value key, Value val) {
-        return defineOwnMember(env, new KeyCache(key), FieldMember.of(val));
+        return defineOwnMember(env, new KeyCache(key), val);
     }
     public final boolean defineOwnMember(Environment env, String key, Value val) {
-        return defineOwnMember(env, new KeyCache(key), FieldMember.of(val));
+        return defineOwnMember(env, new KeyCache(key), val);
     }
     public final boolean defineOwnMember(Environment env, int key, Value val) {
-        return defineOwnMember(env, new KeyCache(key), FieldMember.of(val));
+        return defineOwnMember(env, new KeyCache(key), val);
     }
     public final boolean defineOwnMember(Environment env, double key, Value val) {
-        return defineOwnMember(env, new KeyCache(key), FieldMember.of(val));
+        return defineOwnMember(env, new KeyCache(key), val);
     }
 
     public final boolean deleteOwnMember(Environment env, Value key) {
@@ -238,7 +245,7 @@ public abstract class Value {
             }
         }
 
-        if (defineOwnMember(env, key, FieldMember.of(val))) {
+        if (defineOwnMember(env, key, val)) {
             if (val instanceof FunctionValue) ((FunctionValue)val).setName(key.toString(env));
             return true;
         }
@@ -475,7 +482,13 @@ public abstract class Value {
 
                     var member = obj.getOwnMember(env, entry);
                     if (member instanceof FieldMember field) res.append(field.get(env, obj).toReadable(env, passed, tab + 1));
-                    else res.append("[property]");
+                    else if (member instanceof PropertyMember prop) {
+                        if (prop.getter == null && prop.setter == null) res.append("[No accessors]");
+                        else if (prop.getter == null) res.append("[Setter]");
+                        else if (prop.setter == null) res.append("[Getter]");
+                        else res.append("[Getter/Setter]");
+                    }
+                    else res.append("[???]");
 
                     res.append(",\n");
                 }
@@ -485,7 +498,13 @@ public abstract class Value {
 
                     var member = obj.getOwnMember(env, entry);
                     if (member instanceof FieldMember field) res.append(field.get(env, obj).toReadable(env, passed, tab + 1));
-                    else res.append("[property]");
+                    else if (member instanceof PropertyMember prop) {
+                        if (prop.getter == null && prop.setter == null) res.append("[No accessors]");
+                        else if (prop.getter == null) res.append("[Setter]");
+                        else if (prop.setter == null) res.append("[Getter]");
+                        else res.append("[Getter/Setter]");
+                    }
+                    else res.append("[???]");
 
                     res.append(",\n");
                 }
@@ -520,8 +539,8 @@ public abstract class Value {
         return new NativeFunction("", args -> {
             var obj = new ObjectValue();
 
-            if (!it.hasNext()) obj.defineOwnMember(args.env, "done", FieldMember.of(BoolValue.TRUE));
+            if (!it.hasNext()) obj.defineOwnMember(args.env, "done", BoolValue.TRUE);
-            else obj.defineOwnMember(args.env, "value", FieldMember.of(it.next()));
+            else obj.defineOwnMember(args.env, "value", it.next());
 
             return obj;
         });

src/main/java/me/topchetoeu/jscript/runtime/values/functions/FunctionValue.java

@@ -10,6 +10,8 @@ import me.topchetoeu.jscript.runtime.values.primitives.NumberValue;
 import me.topchetoeu.jscript.runtime.values.primitives.StringValue;
 
 public abstract class FunctionValue extends ObjectValue {
+    private static final StringValue typeString = new StringValue("function");
+
     public String name = "";
     public int length;
     public Value prototype = new ObjectValue();
@@ -17,7 +19,7 @@ public abstract class FunctionValue extends ObjectValue {
     public boolean enableCall = true;
     public boolean enableNew = true;
 
-    private final FieldMember nameField = new FieldMember(true, false, false) {
+    private final FieldMember nameField = new FieldMember(this, true, false, false) {
         @Override public Value get(Environment env, Value self) {
             if (name == null) return new StringValue("");
             return new StringValue(name);
@@ -27,7 +29,7 @@ public abstract class FunctionValue extends ObjectValue {
             return true;
         }
     };
-    private final FieldMember lengthField = new FieldMember(true, false, false) {
+    private final FieldMember lengthField = new FieldMember(this, true, false, false) {
         @Override public Value get(Environment env, Value self) {
             return new NumberValue(length);
         }
@@ -35,7 +37,7 @@ public abstract class FunctionValue extends ObjectValue {
             return false;
         }
     };
-    private final FieldMember prototypeField = new FieldMember(false, false, true) {
+    private final FieldMember prototypeField = new FieldMember(this, false, false, true) {
         @Override public Value get(Environment env, Value self) {
             return prototype;
         }
@@ -77,6 +79,8 @@ public abstract class FunctionValue extends ObjectValue {
         }
     }
 
+    @Override public StringValue type() { return typeString; }
+
     public void setName(String val) {
         if (this.name == null || this.name.equals("")) this.name = val;
     }
@@ -88,7 +92,7 @@ public abstract class FunctionValue extends ObjectValue {
         this.length = length;
         this.name = name;
 
-        prototype.defineOwnMember(null, "constructor", FieldMember.of(this));
+        prototype.defineOwnMember(null, "constructor", this);
     }
 }
 

src/main/java/me/topchetoeu/jscript/runtime/values/objects/ObjectValue.java

@@ -20,13 +20,6 @@ public class ObjectValue extends Value {
         public ObjectValue get(Environment env);
     }
 
-    public static enum State {
-        NORMAL,
-        NO_EXTENSIONS,
-        SEALED,
-        FROZEN,
-    }
-
     public static class Property { 
         public final FunctionValue getter;
         public final FunctionValue setter;
@@ -41,8 +34,6 @@ public class ObjectValue extends Value {
 
     protected PrototypeProvider prototype;
 
-    public boolean extensible = true;
-
     public LinkedHashMap<String, Member> members = new LinkedHashMap<>();
     public LinkedHashMap<SymbolValue, Member> symbolMembers = new LinkedHashMap<>();
 
@@ -70,9 +61,17 @@ public class ObjectValue extends Value {
     @Override public NumberValue toNumber(Environment env) { return toPrimitive(env).toNumber(env);  }
     @Override public StringValue type() { return typeString; }
 
+    private State state = State.NORMAL;
+
+    @Override public State getState() { return state; }
+
     public final void preventExtensions() {
-        extensible = false;
+        if (state == State.NORMAL) state = State.NON_EXTENDABLE;
     }
+    public final void seal() {
+        if (state == State.NORMAL || state == State.NON_EXTENDABLE) state = State.SEALED;
+    }
+    @Override public final void freeze() { state = State.FROZEN; }
 
     @Override public Member getOwnMember(Environment env, KeyCache key) {
         if (key.isSymbol()) return symbolMembers.get(key.toSymbol());
@@ -80,7 +79,7 @@ public class ObjectValue extends Value {
     }
     @Override public boolean defineOwnMember(Environment env, KeyCache key, Member member) {
         var old = getOwnMember(env, key);
-        if (old != null && old.configure(env, member, this)) return true;
+        if (old != null && old.redefine(env, member, this)) return true;
         if (old != null && !old.configurable()) return false;
 
         if (key.isSymbol()) symbolMembers.put(key.toSymbol(), member);
@@ -89,11 +88,11 @@ public class ObjectValue extends Value {
         return true;
     }
     @Override public boolean deleteOwnMember(Environment env, KeyCache key) {
-        if (!extensible) return false;
+        if (!getState().extendable) return false;
 
         var member = getOwnMember(env, key);
         if (member == null) return true;
-        if (member.configurable()) return false;
+        if (!member.configurable()) return false;
 
         if (key.isSymbol()) symbolMembers.remove(key.toSymbol());
         else members.remove(key.toString(env));
@@ -134,12 +133,12 @@ public class ObjectValue extends Value {
     }
 
     public final boolean setPrototype(PrototypeProvider val) {
-        if (!extensible) return false;
+        if (!getState().extendable) return false;
         prototype = val;
         return true;
     }
     public final boolean setPrototype(Key<ObjectValue> key) {
-        if (!extensible) return false;
+        if (!getState().extendable) return false;
         prototype = env -> env.get(key);
         return true;
     }

src/main/java/me/topchetoeu/jscript/runtime/values/objects/ScopeValue.java

@@ -5,20 +5,20 @@ import me.topchetoeu.jscript.runtime.values.Value;
 import me.topchetoeu.jscript.runtime.values.Member.FieldMember;
 
 public final class ScopeValue extends ObjectValue {
-    private class VariableField extends FieldMember {
+    private static class VariableField extends FieldMember {
         private int i;
 
-        public VariableField(int i) {
+        public VariableField(int i, ScopeValue self) {
-            super(false, true, true);
+            super(self, false, true, true);
             this.i = i;
         }
 
         @Override public Value get(Environment env, Value self) {
-            return variables[i][0];
+            return ((ScopeValue)self).variables[i][0];
         }
 
         @Override public boolean set(Environment env, Value val, Value self) {
-            variables[i][0] = val;
+            ((ScopeValue)self).variables[i][0] = val;
             return true;
         }
     }
@@ -28,7 +28,7 @@ public final class ScopeValue extends ObjectValue {
     public ScopeValue(Value[][] variables, String[] names) {
         this.variables = variables;
         for (var i = 0; i < names.length && i < variables.length; i++) {
-            defineOwnMember(Environment.empty(), i, new VariableField(i));
+            defineOwnMember(Environment.empty(), i, new VariableField(i, this));
         }
     }
 }

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/PrimitiveValue.java

@@ -19,4 +19,10 @@ public abstract class PrimitiveValue extends Value {
     @Override public Member getOwnMember(Environment env, KeyCache key) { return null; }
     @Override public Set<String> getOwnMembers(Environment env, boolean onlyEnumerable) { return Set.of(); }
     @Override public Set<SymbolValue> getOwnSymbolMembers(Environment env, boolean onlyEnumerable) { return Set.of(); }
+
+    @Override public State getState() { return State.FROZEN; }
+
+    @Override public void preventExtensions() {}
+    @Override public void seal() {}
+    @Override public void freeze() {}
 }

src/main/java/me/topchetoeu/jscript/runtime/values/primitives/StringValue.java

@@ -40,10 +40,10 @@ public final class StringValue extends PrimitiveValue {
         var i = key.toInt(env);
 
         if (i == num && i >= 0 && i < value.length()) {
-            return FieldMember.of(new StringValue(value.charAt(i) + ""), false, true, false);
+            return FieldMember.of(this, new StringValue(value.charAt(i) + ""), false, true, false);
         }
         else if (key.toString(env).equals("length")) {
-            return FieldMember.of(new NumberValue(value.length()), false, false, false);
+            return FieldMember.of(this, new NumberValue(value.length()), false, false, false);
         }
         else return super.getOwnMember(env, key);
     }