refactor: some code cleanup, emit better bytecode

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

@@ -1,19 +0,0 @@
-package me.topchetoeu.jscript.compilation;
-
-import java.util.List;
-
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-
-public abstract class AssignStatement extends Statement {
-    public abstract void compile(List<Instruction> target, ScopeRecord scope, boolean retPrevValue);
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        compile(target, scope, false);
-    }
-
-    protected AssignStatement(Location loc) {
-        super(loc);
-    }
-}

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

@@ -4,7 +4,7 @@ import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.engine.Operation;
 
 public abstract class AssignableStatement extends Statement {
-    public abstract AssignStatement toAssign(Statement val, Operation operation);
+    public abstract Statement toAssign(Statement val, Operation operation);
 
     protected AssignableStatement(Location loc) {
         super(loc);

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

@@ -1,11 +0,0 @@
-package me.topchetoeu.jscript.compilation;
-
-public class CompileOptions {
-    public final boolean emitBpMap;
-    public final boolean emitVarNames;
-
-    public CompileOptions(boolean emitBpMap, boolean emitVarNames) {
-        this.emitBpMap = emitBpMap;
-        this.emitVarNames = emitVarNames;
-    }
-}

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

@@ -13,16 +13,6 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public class CompoundStatement extends Statement {
     public final Statement[] statements;
 
-    @Override
-    public boolean pollutesStack() {
-        for (var stm : statements) {
-            if (stm instanceof FunctionStatement) continue;
-            return true;
-        }
-
-        return false;
-    }
-
     @Override
     public void declare(ScopeRecord varsScope) {
         for (var stm : statements) {
@@ -31,7 +21,7 @@ public class CompoundStatement extends Statement {
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         for (var stm : statements) {
             if (stm instanceof FunctionStatement) {
                 int start = target.size();
@@ -45,8 +35,8 @@ public class CompoundStatement extends Statement {
             var stm = statements[i];
             
             if (stm instanceof FunctionStatement) continue;
-            if (i != statements.length - 1) stm.compileNoPollution(target, scope, true);
+            if (i != statements.length - 1) stm.compileWithDebug(target, scope, false);
-            else stm.compileWithPollution(target, scope);
+            else stm.compileWithDebug(target, scope, pollute);
         }
     }
 

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

@@ -10,13 +10,9 @@ public class DiscardStatement extends Statement {
     public final Statement value;
 
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
+        value.compile(target, scope, false);
-    @Override
+        
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        if (value == null) return;
-        value.compile(target, scope);
-        if (value.pollutesStack()) target.add(Instruction.discard());
     }
     @Override
     public Statement optimize() {

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

@@ -7,7 +7,6 @@ import me.topchetoeu.jscript.exceptions.SyntaxException;
 public class Instruction {
     public static enum Type {
         RETURN,
-        SIGNAL,
         THROW,
         THROW_SYNTAX,
         DELETE,
@@ -162,12 +161,6 @@ public class Instruction {
         return new Instruction(null, Type.NOP, args);
     }
 
-    /**
-     * ATTENTION: Usage outside of try/catch is broken af
-     */
-    public static Instruction signal(String name) {
-        return new Instruction(null, Type.SIGNAL, name);
-    }
     public static Instruction nop(Object ...params) {
         for (var param : params) {
             if (param instanceof String) continue;

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

@@ -8,29 +8,15 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public abstract class Statement {
     private Location _loc;
 
-    public abstract boolean pollutesStack();
     public boolean pure() { return false; }
-    public abstract void compile(List<Instruction> target, ScopeRecord scope);
+    public abstract void compile(List<Instruction> target, ScopeRecord scope, boolean pollute);
     public void declare(ScopeRecord varsScope) { }
     public Statement optimize() { return this; }
 
-    public void compileNoPollution(List<Instruction> target, ScopeRecord scope, boolean debug) {
+    public void compileWithDebug(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         int start = target.size();
-        compile(target, scope);
+        compile(target, scope, pollute);
-        if (debug && target.size() != start) target.get(start).setDebug(true);
+        if (target.size() != start) target.get(start).setDebug(true);
-        if (pollutesStack()) target.add(Instruction.discard().locate(loc()));
-    }
-    public void compileWithPollution(List<Instruction> target, ScopeRecord scope, boolean debug) {
-        int start = target.size();
-        compile(target, scope);
-        if (debug && target.size() != start) target.get(start).setDebug(true);
-        if (!pollutesStack()) target.add(Instruction.loadValue(null).locate(loc()));
-    }
-    public void compileNoPollution(List<Instruction> target, ScopeRecord scope) {
-        compileNoPollution(target, scope, false);
-    }
-    public void compileWithPollution(List<Instruction> target, ScopeRecord scope) {
-        compileWithPollution(target, scope, false);
     }
 
     public Location loc() { return _loc; }

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

@@ -19,8 +19,6 @@ public class VariableDeclareStatement extends Statement {
 
     public final List<Pair> values;
 
-    @Override
-    public boolean pollutesStack() { return false; }
     @Override
     public void declare(ScopeRecord varsScope) {
         for (var key : values) {
@@ -28,7 +26,7 @@ public class VariableDeclareStatement extends Statement {
         }
     }
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         for (var entry : values) {
             if (entry.name == null) continue;
             var key = scope.getKey(entry.name);
@@ -39,10 +37,12 @@ public class VariableDeclareStatement extends Statement {
                 target.add(Instruction.storeVar(key).locate(loc()));
             }
             else if (entry.value != null) {
-                entry.value.compileWithPollution(target, scope);
+                entry.value.compile(target, scope, true);
                 target.add(Instruction.storeVar(key).locate(loc()));
             }
         }
+
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public VariableDeclareStatement(Location loc, List<Pair> values) {

src/me/topchetoeu/jscript/compilation/control/ArrayStatement.java

@@ -1,37 +1,36 @@
-package me.topchetoeu.jscript.compilation.values;
+package me.topchetoeu.jscript.compilation.control;
-
+
-import java.util.List;
+import java.util.List;
-
+
-import me.topchetoeu.jscript.Location;
+import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.Instruction;
+import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
+import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
+import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-
+
-public class ArrayStatement extends Statement {
+public class ArrayStatement extends Statement {
-    public final Statement[] statements;
+    public final Statement[] statements;
-
+
-    @Override
+    @Override
-    public boolean pollutesStack() { return true; }
+    public boolean pure() { return true; }
-    @Override
+
-    public boolean pure() { return true; }
+    @Override
-
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-    @Override
+        target.add(Instruction.loadArr(statements.length).locate(loc()));
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+        var i = 0;
-        target.add(Instruction.loadArr(statements.length).locate(loc()));
+        for (var el : statements) {
-        var i = 0;
+            if (el != null) {
-        for (var el : statements) {
+                target.add(Instruction.dup().locate(loc()));
-            if (el != null) {
+                target.add(Instruction.loadValue(i).locate(loc()));
-                target.add(Instruction.dup().locate(loc()));
+                el.compile(target, scope, true);
-                target.add(Instruction.loadValue(i).locate(loc()));
+                target.add(Instruction.storeMember().locate(loc()));
-                el.compileWithPollution(target, scope);
+            }
-                target.add(Instruction.storeMember().locate(loc()));
+            i++;
-            }
+        }
-            i++;
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
-        }
+    }
-    }
+
-
+    public ArrayStatement(Location loc, Statement[] statements) {
-    public ArrayStatement(Location loc, Statement[] statements) {
+        super(loc);
-        super(loc);
+        this.statements = statements;
-        this.statements = statements;
+    }
-    }
+}
-}

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

@@ -11,11 +11,9 @@ public class BreakStatement extends Statement {
     public final String label;
 
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         target.add(Instruction.nop("break", label).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public BreakStatement(Location loc, String label) {

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

@@ -11,11 +11,9 @@ public class ContinueStatement extends Statement {
     public final String label;
 
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         target.add(Instruction.nop("cont", label).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public ContinueStatement(Location loc, String label) {

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

@@ -9,11 +9,9 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 
 public class DebugStatement extends Statement {
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         target.add(Instruction.debug().locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public DebugStatement(Location loc) {

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

@@ -12,13 +12,12 @@ public class DeleteStatement extends Statement {
     public final Statement value;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
+        value.compile(target, scope, true);
+        key.compile(target, scope, true);
 
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        value.compile(target, scope);
-        key.compile(target, scope);
         target.add(Instruction.delete().locate(loc()));
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public DeleteStatement(Location loc, Statement key, Statement value) {

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

@@ -14,19 +14,16 @@ public class DoWhileStatement extends Statement {
     public final Statement condition, body;
     public final String label;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         body.declare(globScope);
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (condition instanceof ConstantStatement) {
             int start = target.size();
-            body.compileNoPollution(target, scope);
+            body.compile(target, scope, false);
             int end = target.size();
             if (Values.toBoolean(((ConstantStatement)condition).value)) {
                 WhileStatement.replaceBreaks(target, label, start, end, end + 1, end + 1);
@@ -35,13 +32,14 @@ public class DoWhileStatement extends Statement {
                 target.add(Instruction.jmp(start - end).locate(loc()));
                 WhileStatement.replaceBreaks(target, label, start, end, start, end + 1);
             }
+            if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
             return;
         }
 
         int start = target.size();
-        body.compileNoPollution(target, scope, true);
+        body.compileWithDebug(target, scope, false);
         int mid = target.size();
-        condition.compileWithPollution(target, scope);
+        condition.compile(target, scope, true);
         int end = target.size();
 
         WhileStatement.replaceBreaks(target, label, start, mid - 1, mid, end + 1);

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

@@ -14,9 +14,6 @@ public class ForInStatement extends Statement {
     public final Statement varValue, object, body;
     public final String label;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         body.declare(globScope);
@@ -24,16 +21,16 @@ public class ForInStatement extends Statement {
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         var key = scope.getKey(varName);
         if (key instanceof String) target.add(Instruction.makeVar((String)key));
 
         if (varValue != null) {
-            varValue.compileWithPollution(target, scope);
+            varValue.compile(target, scope, true);
             target.add(Instruction.storeVar(scope.getKey(varName)));
         }
 
-        object.compileWithPollution(target, scope);
+        object.compile(target, scope, true);
         target.add(Instruction.keys());
         
         int start = target.size();
@@ -58,8 +55,7 @@ public class ForInStatement extends Statement {
 
         for (var i = start; i < target.size(); i++) target.get(i).locate(loc());
 
-        body.compileNoPollution(target, scope, true);
+        body.compileWithDebug(target, scope, false);
-
 
         int end = target.size();
 
@@ -68,6 +64,7 @@ public class ForInStatement extends Statement {
         target.add(Instruction.jmp(start - end).locate(loc()));
         target.add(Instruction.discard().locate(loc()));
         target.set(mid, Instruction.jmpIf(end - mid + 1).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public ForInStatement(Location loc, String label, boolean isDecl, String varName, Statement varValue, Statement object, Statement body) {

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

@@ -14,44 +14,43 @@ public class ForStatement extends Statement {
     public final Statement declaration, assignment, condition, body;
     public final String label;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         declaration.declare(globScope);
         body.declare(globScope);
     }
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-        declaration.compile(target, scope);
+        declaration.compile(target, scope, false);
 
         if (condition instanceof ConstantStatement) {
             if (Values.toBoolean(((ConstantStatement)condition).value)) {
                 int start = target.size();
-                body.compileNoPollution(target, scope);
+                body.compile(target, scope, false);
                 int mid = target.size();
-                assignment.compileNoPollution(target, scope, true);
+                assignment.compileWithDebug(target, scope, false);
                 int end = target.size();
                 WhileStatement.replaceBreaks(target, label, start, mid, mid, end + 1);
                 target.add(Instruction.jmp(start - target.size()).locate(loc()));
-                return;
+                if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
             }
+            return;
         }
 
         int start = target.size();
-        condition.compileWithPollution(target, scope);
+        condition.compile(target, scope, true);
         int mid = target.size();
         target.add(Instruction.nop());
-        body.compileNoPollution(target, scope);
+        body.compile(target, scope, false);
         int beforeAssign = target.size();
-        assignment.compile(target, scope);
+        assignment.compileWithDebug(target, scope, false);
         int end = target.size();
 
         WhileStatement.replaceBreaks(target, label, mid + 1, end, beforeAssign, end + 1);
 
         target.add(Instruction.jmp(start - end).locate(loc()));
         target.set(mid, Instruction.jmpIfNot(end - mid + 1).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
     @Override
     public Statement optimize() {

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

@@ -14,9 +14,6 @@ import me.topchetoeu.jscript.engine.values.Values;
 public class IfStatement extends Statement {
     public final Statement condition, body, elseBody;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         body.declare(globScope);
@@ -24,33 +21,34 @@ public class IfStatement extends Statement {
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (condition instanceof ConstantStatement) {
             if (Values.not(((ConstantStatement)condition).value)) {
-                if (elseBody != null) elseBody.compileNoPollution(target, scope, true);
+                if (elseBody != null) elseBody.compileWithDebug(target, scope, pollute);
             }
             else {
-                body.compileNoPollution(target, scope, true);
+                body.compileWithDebug(target, scope, pollute);
             }
 
             return;
         }
 
-        condition.compileWithPollution(target, scope);
+        condition.compile(target, scope, true);
+
         if (elseBody == null) {
             int i = target.size();
             target.add(Instruction.nop());
-            body.compileNoPollution(target, scope, true);
+            body.compileWithDebug(target, scope, pollute);
             int endI = target.size();
             target.set(i, Instruction.jmpIfNot(endI - i).locate(loc()));
         }
         else {
             int start = target.size();
             target.add(Instruction.nop());
-            body.compileNoPollution(target, scope, true);
+            body.compileWithDebug(target, scope, pollute);
             target.add(Instruction.nop());
             int mid = target.size();
-            elseBody.compileNoPollution(target, scope, true);
+            elseBody.compileWithDebug(target, scope, pollute);
             int end = target.size();
 
             target.set(start, Instruction.jmpIfNot(mid - start).locate(loc()));

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

@@ -11,12 +11,9 @@ public class ReturnStatement extends Statement {
     public final Statement value;
 
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         if (value == null) target.add(Instruction.loadValue(null).locate(loc()));
-        else value.compileWithPollution(target, scope);
+        else value.compile(target, scope, true);
         target.add(Instruction.ret().locate(loc()));
     }
 

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

@@ -21,9 +21,6 @@ public class SwitchStatement extends Statement {
         }
     }
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     public final Statement value;
     public final SwitchCase[] cases;
     public final Statement[] body;
@@ -35,15 +32,15 @@ public class SwitchStatement extends Statement {
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         var caseMap = new HashMap<Integer, Integer>();
         var stmIndexMap = new HashMap<Integer, Integer>();
 
-        value.compile(target, scope);
+        value.compile(target, scope, true);
 
         for (var ccase : cases) {
             target.add(Instruction.dup().locate(loc()));
-            ccase.value.compileWithPollution(target, scope);
+            ccase.value.compile(target, scope, true);
             target.add(Instruction.operation(Operation.EQUALS).locate(loc()));
             caseMap.put(target.size(), ccase.statementI);
             target.add(Instruction.nop());
@@ -55,7 +52,7 @@ public class SwitchStatement extends Statement {
 
         for (var stm : body) {
             stmIndexMap.put(stmIndexMap.size(), target.size());
-            stm.compileNoPollution(target, scope, true);
+            stm.compileWithDebug(target, scope, false);
         }
 
         if (defaultI < 0 || defaultI >= body.length) target.set(start, Instruction.jmp(target.size() - start).locate(loc()));

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

@@ -11,11 +11,8 @@ public class ThrowStatement extends Statement {
     public final Statement value;
 
     @Override
-    public boolean pollutesStack() { return false; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
+        value.compile(target, scope, true);
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        value.compileWithPollution(target, scope);
         target.add(Instruction.throwInstr().locate(loc()));
     }
 

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

@@ -15,9 +15,6 @@ public class TryStatement extends Statement {
     public final Statement finallyBody;
     public final String name;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         tryBody.declare(globScope);
@@ -26,30 +23,31 @@ public class TryStatement extends Statement {
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         target.add(Instruction.nop());
 
         int start = target.size(), tryN, catchN = -1, finN = -1;
 
-        tryBody.compileNoPollution(target, scope);
+        tryBody.compile(target, scope, false);
         tryN = target.size() - start;
 
         if (catchBody != null) {
             int tmp = target.size();
             var local = scope instanceof GlobalScope ? scope.child() : (LocalScopeRecord)scope;
             local.define(name, true);
-            catchBody.compileNoPollution(target, scope);
+            catchBody.compile(target, scope, false);
             local.undefine();
             catchN = target.size() - tmp;
         }
 
         if (finallyBody != null) {
             int tmp = target.size();
-            finallyBody.compileNoPollution(target, scope);
+            finallyBody.compile(target, scope, false);
             finN = target.size() - tmp;
         }
 
         target.set(start - 1, Instruction.tryInstr(tryN, catchN, finN).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public TryStatement(Location loc, Statement tryBody, Statement catchBody, Statement finallyBody, String name) {

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

@@ -16,19 +16,16 @@ public class WhileStatement extends Statement {
     public final Statement condition, body;
     public final String label;
 
-    @Override
-    public boolean pollutesStack() { return false; }
-
     @Override
     public void declare(ScopeRecord globScope) {
         body.declare(globScope);
     }
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (condition instanceof ConstantStatement) {
             if (Values.toBoolean(((ConstantStatement)condition).value)) {
                 int start = target.size();
-                body.compileNoPollution(target, scope);
+                body.compile(target, scope, false);
                 int end = target.size();
                 replaceBreaks(target, label, start, end, start, end + 1);
                 target.add(Instruction.jmp(start - target.size()).locate(loc()));
@@ -37,10 +34,10 @@ public class WhileStatement extends Statement {
         }
 
         int start = target.size();
-        condition.compileWithPollution(target, scope);
+        condition.compile(target, scope, true);
         int mid = target.size();
         target.add(Instruction.nop());
-        body.compileNoPollution(target, scope);
+        body.compile(target, scope, false);
 
         int end = target.size();
 
@@ -48,6 +45,7 @@ public class WhileStatement extends Statement {
 
         target.add(Instruction.jmp(start - end).locate(loc()));
         target.set(mid, Instruction.jmpIfNot(end - mid + 1).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
     @Override
     public Statement optimize() {

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

@@ -12,23 +12,19 @@ public class CallStatement extends Statement {
     public final Statement[] args;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         if (func instanceof IndexStatement) {
-            ((IndexStatement)func).compile(target, scope, true);
+            ((IndexStatement)func).compile(target, scope, true, true);
         }
         else {
-            target.add(Instruction.loadValue(null).locate(loc()));
+               target.add(Instruction.loadValue(null).locate(loc()));
-            func.compileWithPollution(target, scope);
+            func.compile(target, scope, true);
         }
 
-        for (var arg : args) {
+        for (var arg : args) arg.compile(target, scope, true);
-            arg.compileWithPollution(target, scope);
-        }
 
         target.add(Instruction.call(args.length).locate(loc()).setDebug(true));
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public CallStatement(Location loc, Statement func, Statement ...args) {

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

@@ -15,11 +15,9 @@ public class ChangeStatement extends Statement {
     public final boolean postfix;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         value.toAssign(new ConstantStatement(loc(), -addAmount), Operation.SUBTRACT).compile(target, scope, postfix);
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public ChangeStatement(Location loc, AssignableStatement value, double addAmount, boolean postfix) {

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

@@ -1,38 +0,0 @@
-package me.topchetoeu.jscript.compilation.values;
-
-import java.util.List;
-
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-
-public class CommaStatement extends Statement {
-    public final Statement first;
-    public final Statement second;
-
-    @Override
-    public boolean pollutesStack() { return true; }
-    @Override
-    public boolean pure() { return first.pure() && second.pure(); }
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        first.compileNoPollution(target, scope);
-        second.compileWithPollution(target, scope);
-    }
-
-    @Override
-    public Statement optimize() {
-        var f = first.optimize();
-        var s = second.optimize();
-        if (f.pure()) return s;
-        else return new CommaStatement(loc(), f, s);
-    }
-
-    public CommaStatement(Location loc, Statement first, Statement second) {
-        super(loc);
-        this.first = first;
-        this.second = second;
-    }
-}

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

@@ -10,14 +10,12 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public class ConstantStatement extends Statement {
     public final Object value;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-        target.add(Instruction.loadValue(value).locate(loc()));
+        if (pollute) target.add(Instruction.loadValue(value).locate(loc()));
     }
 
     public ConstantStatement(Location loc, Object val) {

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

@@ -17,8 +17,6 @@ public class FunctionStatement extends Statement {
 
     @Override
     public boolean pure() { return name == null; }
-    @Override
-    public boolean pollutesStack() { return true; }
 
     @Override
     public void declare(ScopeRecord scope) {
@@ -69,7 +67,7 @@ public class FunctionStatement extends Statement {
 
         body.declare(subscope);
         target.add(Instruction.debugVarNames(subscope.locals()));
-        body.compile(target, subscope);
+        body.compile(target, subscope, false);
 
         checkBreakAndCont(target, start);
 
@@ -90,12 +88,13 @@ public class FunctionStatement extends Statement {
             var key = scope.getKey(this.name);
 
             if (key instanceof String) target.add(Instruction.makeVar((String)key).locate(loc()));
-            target.add(Instruction.storeVar(scope.getKey(this.name), true).locate(loc()));
+            target.add(Instruction.storeVar(scope.getKey(this.name), false).locate(loc()));
         }
     }
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         compile(target, scope, null, false);
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public FunctionStatement(Location loc, String name, String[] args, CompoundStatement body) {

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

@@ -8,14 +8,12 @@ import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 
 public class GlobalThisStatement extends Statement {
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-        target.add(Instruction.loadGlob().locate(loc()));
+        if (pollute) target.add(Instruction.loadGlob().locate(loc()));
     }
 
     public GlobalThisStatement(Location loc) {

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

@@ -3,49 +3,37 @@ package me.topchetoeu.jscript.compilation.values;
 import java.util.List;
 
 import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.AssignStatement;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
 import me.topchetoeu.jscript.engine.Operation;
 import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 
-public class IndexAssignStatement extends AssignStatement {
+public class IndexAssignStatement extends Statement {
     public final Statement object;
     public final Statement index;
     public final Statement value;
     public final Operation operation;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope, boolean retPrevValue) {
-        int start = 0;
-
         if (operation != null) {
-            object.compileWithPollution(target, scope);
+            object.compile(target, scope, true);
-            index.compileWithPollution(target, scope);
+            index.compile(target, scope, true);
             target.add(Instruction.dup(2, 0).locate(loc()));
 
             target.add(Instruction.loadMember().locate(loc()));
-            if (retPrevValue) {
+            value.compile(target, scope, true);
-                target.add(Instruction.dup().locate(loc()));
-                target.add(Instruction.move(3, 1).locate(loc()));
-            }
-            value.compileWithPollution(target, scope);
             target.add(Instruction.operation(operation).locate(loc()));
 
-            target.add(Instruction.storeMember(!retPrevValue).locate(loc()).setDebug(true));
+            target.add(Instruction.storeMember(pollute).locate(loc()).setDebug(true));
         }
         else {
-            object.compileWithPollution(target, scope);
+            object.compile(target, scope, true);
-            if (retPrevValue) target.add(Instruction.dup().locate(loc()));
+            index.compile(target, scope, true);
-            index.compileWithPollution(target, scope);
+            value.compile(target, scope, true);
-            value.compileWithPollution(target, scope);
 
-            target.add(Instruction.storeMember(!retPrevValue).locate(loc()).setDebug(true));
+            target.add(Instruction.storeMember(pollute).locate(loc()).setDebug(true));
         }
-        target.get(start);
     }
 
     public IndexAssignStatement(Location loc, Statement object, Statement index, Statement value, Operation operation) {

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

@@ -3,7 +3,6 @@ package me.topchetoeu.jscript.compilation.values;
 import java.util.List;
 
 import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.AssignStatement;
 import me.topchetoeu.jscript.compilation.AssignableStatement;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
@@ -14,31 +13,30 @@ public class IndexStatement extends AssignableStatement {
     public final Statement object;
     public final Statement index;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public AssignStatement toAssign(Statement val, Operation operation) {
+    public Statement toAssign(Statement val, Operation operation) {
         return new IndexAssignStatement(loc(), object, index, val, operation);
     }
-    public void compile(List<Instruction> target, ScopeRecord scope, boolean dupObj) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean dupObj, boolean pollute) {
         int start = 0;
-        object.compileWithPollution(target, scope);
+        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()));
             return;
         }
 
-        index.compileWithPollution(target, scope);
+        index.compile(target, scope, true);
         target.add(Instruction.loadMember().locate(loc()));
         target.get(start).setDebug(true);
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-        compile(target, scope, false);
+        compile(target, scope, false, pollute);
     }
 
     public IndexStatement(Location loc, Statement object, Statement index) {

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

@@ -11,29 +11,27 @@ import me.topchetoeu.jscript.engine.values.Values;
 public class LazyAndStatement extends Statement {
     public final Statement first, second;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() {
         return first.pure() && second.pure();
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (first instanceof ConstantStatement) {
             if (Values.not(((ConstantStatement)first).value)) {
-                first.compileWithPollution(target, scope);
+                first.compile(target, scope, pollute);
             }
-            else second.compileWithPollution(target, scope);
+            else second.compile(target, scope, pollute);
             return;
         }
 
-        first.compileWithPollution(target, scope);
+        first.compile(target, scope, true);
-        target.add(Instruction.dup().locate(loc()));
+        if (pollute) target.add(Instruction.dup().locate(loc()));
         int start = target.size();
         target.add(Instruction.nop());
         target.add(Instruction.discard().locate(loc()));
-        second.compileWithPollution(target, scope);
+        second.compile(target, scope, pollute);
         target.set(start, Instruction.jmpIfNot(target.size() - start).locate(loc()));
     }
 

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

@@ -11,29 +11,27 @@ import me.topchetoeu.jscript.engine.values.Values;
 public class LazyOrStatement extends Statement {
     public final Statement first, second;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() {
         return first.pure() && second.pure();
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (first instanceof ConstantStatement) {
             if (Values.not(((ConstantStatement)first).value)) {
-                second.compileWithPollution(target, scope);
+                second.compile(target, scope, pollute);
             }
-            else first.compileWithPollution(target, scope);
+            else first.compile(target, scope, pollute);
             return;
         }
 
-        first.compileWithPollution(target, scope);
+        first.compile(target, scope, true);
-        target.add(Instruction.dup().locate(loc()));
+        if (pollute) target.add(Instruction.dup().locate(loc()));
         int start = target.size();
         target.add(Instruction.nop());
         target.add(Instruction.discard().locate(loc()));
-        second.compileWithPollution(target, scope);
+        second.compile(target, scope, pollute);
         target.set(start, Instruction.jmpIf(target.size() - start).locate(loc()));
     }
 

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

@@ -12,14 +12,10 @@ public class NewStatement extends Statement {
     public final Statement[] args;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
+        func.compile(target, scope, true);
 
-    @Override
+        for (var arg : args) arg.compile(target, scope, true);
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        func.compileWithPollution(target, scope);
-        for (var arg : args) {
-            arg.compileWithPollution(target, scope);
-        }
 
         target.add(Instruction.callNew(args.length).locate(loc()).setDebug(true));
     }

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

@@ -15,10 +15,7 @@ public class ObjectStatement extends Statement {
     public final Map<Object, FunctionStatement> setters;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
         target.add(Instruction.loadObj().locate(loc()));
 
         for (var el : map.entrySet()) {
@@ -26,7 +23,7 @@ public class ObjectStatement extends Statement {
             target.add(Instruction.loadValue(el.getKey()).locate(loc()));
             var val = el.getValue();
             if (val instanceof FunctionStatement) ((FunctionStatement)val).compile(target, scope, el.getKey().toString(), false);
-            else val.compileWithPollution(target, scope);
+            else val.compile(target, scope, true);
             target.add(Instruction.storeMember().locate(loc()));
         }
 
@@ -38,14 +35,16 @@ public class ObjectStatement extends Statement {
             if (key instanceof String) target.add(Instruction.loadValue((String)key).locate(loc()));
             else target.add(Instruction.loadValue((Double)key).locate(loc()));
 
-            if (getters.containsKey(key)) getters.get(key).compileWithPollution(target, scope);
+            if (getters.containsKey(key)) getters.get(key).compile(target, scope, true);
             else target.add(Instruction.loadValue(null).locate(loc()));
 
-            if (setters.containsKey(key)) setters.get(key).compileWithPollution(target, scope);
+            if (setters.containsKey(key)) setters.get(key).compile(target, scope, true);
             else target.add(Instruction.loadValue(null).locate(loc()));
 
             target.add(Instruction.defProp().locate(loc()));
         }
+
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public ObjectStatement(Location loc, Map<Object, Statement> map, Map<Object, FunctionStatement> getters, Map<Object, FunctionStatement> setters) {

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

@@ -16,15 +16,15 @@ public class OperationStatement extends Statement {
     public final Operation operation;
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         for (var arg : args) {
-            arg.compileWithPollution(target, scope);
+            arg.compile(target, scope, true);
         }
-        target.add(Instruction.operation(operation).locate(loc()));
+
+        if (pollute) target.add(Instruction.operation(operation).locate(loc()));
+        else target.add(Instruction.discard().locate(loc()));
     }
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() {
         for (var arg : args) {

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

@@ -10,14 +10,13 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public class RegexStatement extends Statement {
     public final String pattern, flags;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         target.add(Instruction.loadRegex(pattern, flags).locate(loc()));
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public RegexStatement(Location loc, String pattern, String flags) {

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

@@ -1,58 +0,0 @@
-package me.topchetoeu.jscript.compilation.values;
-
-import java.util.List;
-
-import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.Instruction;
-import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.engine.scope.ScopeRecord;
-import me.topchetoeu.jscript.engine.values.Values;
-
-public class TernaryStatement extends Statement {
-    public final Statement condition;
-    public final Statement first;
-    public final Statement second;
-
-    @Override
-    public boolean pollutesStack() { return true; }
-    @Override
-    public boolean pure() { return true; }
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        if (condition instanceof ConstantStatement) {
-            if (!Values.toBoolean(((ConstantStatement)condition).value)) {
-                second.compileWithPollution(target, scope);
-            }
-            else first.compileWithPollution(target, scope);
-            return;
-        }
-
-        condition.compileWithPollution(target, scope);
-        int start = target.size();
-        target.add(Instruction.nop());
-        first.compileWithPollution(target, scope);
-        int mid = target.size();
-        target.add(Instruction.nop());
-        second.compileWithPollution(target, scope);
-        int end = target.size();
-
-        target.set(start, Instruction.jmpIfNot(mid - start + 1).locate(loc()));
-        target.set(mid, Instruction.jmp(end - mid).locate(loc()));
-    }
-
-    @Override
-    public Statement optimize() {
-        var cond = condition.optimize();
-        var f = first.optimize();
-        var s = second.optimize();
-        return new TernaryStatement(loc(), cond, f, s);
-    }
-
-    public TernaryStatement(Location loc, Statement condition, Statement first, Statement second) {
-        super(loc);
-        this.condition = condition;
-        this.first = first;
-        this.second = second;
-    }
-}

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

@@ -5,19 +5,18 @@ import java.util.List;
 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
+import me.topchetoeu.jscript.compilation.control.ArrayStatement;
 import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 import me.topchetoeu.jscript.engine.values.Values;
 
 public class TypeofStatement extends Statement {
     public final Statement value;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         if (value instanceof VariableStatement) {
             var i = scope.getKey(((VariableStatement)value).name);
             if (i instanceof String) {
@@ -25,7 +24,7 @@ public class TypeofStatement extends Statement {
                 return;
             }
         }
-        value.compileWithPollution(target, scope);
+        value.compile(target, scope, pollute);
         target.add(Instruction.typeof().locate(loc()));
     }
 

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

@@ -4,36 +4,32 @@ import java.util.List;
 
 import me.topchetoeu.jscript.Location;
 import me.topchetoeu.jscript.compilation.Statement;
-import me.topchetoeu.jscript.compilation.AssignStatement;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.engine.Operation;
 import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 
-public class VariableAssignStatement extends AssignStatement {
+public class VariableAssignStatement extends Statement {
     public final String name;
     public final Statement value;
     public final Operation operation;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
-    @Override
-    public void compile(List<Instruction> target, ScopeRecord scope, boolean retPrevValue) {
         var i = scope.getKey(name);
         if (operation != null) {
             target.add(Instruction.loadVar(i).locate(loc()));
-            if (retPrevValue) target.add(Instruction.dup().locate(loc()));
             if (value instanceof FunctionStatement) ((FunctionStatement)value).compile(target, scope, name, false);
-            else value.compileWithPollution(target, scope);
+            else value.compile(target, scope, true);
             target.add(Instruction.operation(operation).locate(loc()));
-            target.add(Instruction.storeVar(i, !retPrevValue).locate(loc()));
+            target.add(Instruction.storeVar(i, false).locate(loc()));
         }
         else {
-            if (retPrevValue) target.add(Instruction.loadVar(i).locate(loc()));
             if (value instanceof FunctionStatement) ((FunctionStatement)value).compile(target, scope, name, false);
-            else value.compileWithPollution(target, scope);
+            else value.compile(target, scope, true);
-            target.add(Instruction.storeVar(i, !retPrevValue).locate(loc()));
+            target.add(Instruction.storeVar(i, false).locate(loc()));
         }
+
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     public VariableAssignStatement(Location loc, String name, Statement val, Operation operation) {

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

@@ -10,14 +10,12 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public class VariableIndexStatement extends Statement {
     public final int index;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-        target.add(Instruction.loadVar(index).locate(loc()));
+        if (pollute) target.add(Instruction.loadVar(index).locate(loc()));
     }
 
     public VariableIndexStatement(Location loc, int i) {

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

@@ -3,7 +3,6 @@ package me.topchetoeu.jscript.compilation.values;
 import java.util.List;
 
 import me.topchetoeu.jscript.Location;
-import me.topchetoeu.jscript.compilation.AssignStatement;
 import me.topchetoeu.jscript.compilation.AssignableStatement;
 import me.topchetoeu.jscript.compilation.Instruction;
 import me.topchetoeu.jscript.compilation.Statement;
@@ -13,20 +12,19 @@ import me.topchetoeu.jscript.engine.scope.ScopeRecord;
 public class VariableStatement extends AssignableStatement {
     public final String name;
 
-    @Override
-    public boolean pollutesStack() { return true; }
     @Override
     public boolean pure() { return true; }
 
     @Override
-    public AssignStatement toAssign(Statement val, Operation operation) {
+    public Statement toAssign(Statement val, Operation operation) {
         return new VariableAssignStatement(loc(), name, val, operation);
     }
 
     @Override
-    public void compile(List<Instruction> target, ScopeRecord scope) {
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
         var i = scope.getKey(name);
         target.add(Instruction.loadVar(i).locate(loc()));
+        if (!pollute) target.add(Instruction.discard().locate(loc()));
     }
 
     public VariableStatement(Location loc, String name) {

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

@@ -11,12 +11,9 @@ public class VoidStatement extends Statement {
     public final Statement value;
 
     @Override
-    public boolean pollutesStack() { return true; }
+    public void compile(List<Instruction> target, ScopeRecord scope, boolean pollute) {
-
+        if (value != null) value.compile(target, scope, false);
-    @Override
+        if (pollute) target.add(Instruction.loadValue(null).locate(loc()));
-    public void compile(List<Instruction> target, ScopeRecord scope) {
-        if (value != null) value.compileNoPollution(target, scope);
-        target.add(Instruction.loadValue(null).locate(loc()));
     }
 
     @Override

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

@@ -9,7 +9,6 @@ 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.SignalValue;
 import me.topchetoeu.jscript.engine.values.Symbol;
 import me.topchetoeu.jscript.engine.values.Values;
 import me.topchetoeu.jscript.exceptions.EngineException;
@@ -20,9 +19,6 @@ public class Runners {
     public static Object execReturn(Context ctx, Instruction instr, CodeFrame frame) {
         return frame.pop();
     }
-    public static Object execSignal(Context ctx, Instruction instr, CodeFrame frame) {
-        return new SignalValue(instr.get(0));
-    }
     public static Object execThrow(Context ctx, Instruction instr, CodeFrame frame) {
         throw new EngineException(frame.pop());
     }
@@ -343,11 +339,9 @@ public class Runners {
     }
 
     public static Object exec(Context ctx, Instruction instr, CodeFrame frame) throws InterruptedException {
-        // System.out.println(instr + "@" + instr.location);
         switch (instr.type) {
             case NOP: return execNop(ctx, instr, frame);
             case RETURN: return execReturn(ctx, instr, frame);
-            case SIGNAL: return execSignal(ctx, instr, frame);
             case THROW: return execThrow(ctx, instr, frame);
             case THROW_SYNTAX: return execThrowSyntax(ctx, instr, frame);
             case CALL: return execCall(ctx, instr, frame);

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

@@ -1,17 +0,0 @@
-package me.topchetoeu.jscript.engine.values;
-
-public final class SignalValue {
-    public final String data;
-
-    public SignalValue(String data) {
-        this.data = data;
-    }
-
-    public static boolean isSignal(Object signal, String value) {
-        if (!(signal instanceof SignalValue)) return false;
-        var val = ((SignalValue)signal).data;
-
-        if (value.endsWith("*")) return val.startsWith(value.substring(0, value.length() - 1));
-        else return val.equals(value);
-    }
-}

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

@@ -84,7 +84,6 @@ public class Values {
             obj instanceof String ||
             obj instanceof Boolean ||
             obj instanceof Symbol ||
-            obj instanceof SignalValue ||
             obj == null ||
             obj == NULL;
     }
@@ -143,7 +142,6 @@ public class Values {
         if (val instanceof Boolean) return (Boolean)val ? "true" : "false";
         if (val instanceof String) return (String)val;
         if (val instanceof Symbol) return ((Symbol)val).toString();
-        if (val instanceof SignalValue) return "[signal '" + ((SignalValue)val).data + "']";
 
         return "Unknown value";
     }

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

@@ -1230,7 +1230,7 @@ public class Parsing {
 
         return ParseRes.res(new OperationStatement(loc, Operation.IN, prev, valRes.result), n);
     }
-    public static ParseRes<CommaStatement> parseComma(String filename, List<Token> tokens, int i, Statement prev, int precedence) {
+    public static ParseRes<CompoundStatement> parseComma(String filename, List<Token> tokens, int i, Statement prev, int precedence) {
         var loc = getLoc(filename, tokens, i);
         var n = 0;
 
@@ -1241,9 +1241,9 @@ public class Parsing {
         if (!res.isSuccess()) return ParseRes.error(loc, "Expected a value after the comma.", res);
         n += res.n;
 
-        return ParseRes.res(new CommaStatement(loc, prev, res.result), n);
+        return ParseRes.res(new CompoundStatement(loc, prev, res.result), n);
     }
-    public static ParseRes<TernaryStatement> parseTernary(String filename, List<Token> tokens, int i, Statement prev, int precedence) {
+    public static ParseRes<IfStatement> parseTernary(String filename, List<Token> tokens, int i, Statement prev, int precedence) {
         var loc = getLoc(filename, tokens, i);
         var n = 0;
 
@@ -1260,7 +1260,7 @@ public class Parsing {
         if (!b.isSuccess()) return ParseRes.error(loc, "Expected a second value after the ternary operator.", b);
         n += b.n;
 
-        return ParseRes.res(new TernaryStatement(loc, prev, a.result, b.result), n);
+        return ParseRes.res(new IfStatement(loc, prev, a.result, b.result), n);
     }
     public static ParseRes<? extends Statement> parseOperator(String filename, List<Token> tokens, int i, Statement prev, int precedence) {
         var loc = getLoc(filename, tokens, i);
@@ -1886,7 +1886,7 @@ public class Parsing {
         body.declare(target);
 
         try {
-            body.compile(res, subscope);
+            body.compile(res, subscope, true);
             FunctionStatement.checkBreakAndCont(res, 0);
         }
         catch (SyntaxException e) {