Ast Binding

ASTPlayground/MainForm.fmx

@@ -135,7 +135,7 @@ object Form1: TForm1
     object DebugBox: TCheckBox
       Position.X = 24.000000000000000000
       Position.Y = 360.000000000000000000
-      TabOrder = 17
+      TabOrder = 16
       Text = 'Debug'
     end
   end

ASTPlayground/MainForm.pas

@@ -28,7 +28,8 @@ uses
     Myc.Ast.Evaluator,
     Myc.Ast.Printer,
     FMX.Layouts,
-    FMX.Objects; // Added for TExecutionScope
+    FMX.Objects,
+    Myc.Ast.Scope; // Added for TExecutionScope
 
 type
     // A test record
@@ -80,6 +81,8 @@ type
         FWorkspace: TAuraWorkspace;
         function CreateVisitor(const AScope: IExecutionScope): IAstVisitor;
         procedure WorkspaceMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
+        // New helper function to encapsulate the Bind -> Evaluate pattern
+        function ExecuteAst(const ANode: IExpressionNode; const AScope: IExecutionScope): TAstValue;
     public
     { Public declarations }
     end;
@@ -90,7 +93,7 @@ var
 implementation
 
 uses
-    Myc.Ast.Scope,
+    // Myc.Ast.Scope is now in the interface uses
     Myc.Data.Scalar.JSON,
     Myc.Data.Decimal,
     System.Diagnostics; // For TStopwatch
@@ -115,6 +118,17 @@ begin
         Result := TEvaluatorVisitor.Create(AScope);
 end;
 
+function TForm1.ExecuteAst(const ANode: IExpressionNode; const AScope: IExecutionScope): TAstValue;
+begin
+    // STEP 1: BIND
+    // The binder uses the provided scope to know about native functions etc.
+    TAst.Bind(ANode, AScope);
+
+    // STEP 2: EVALUATE
+    var visitor := CreateVisitor(AScope);
+    Result := ANode.Accept(visitor);
+end;
+
 procedure TForm1.FormCreate(Sender: TObject);
 begin
     FWorkspace := TAuraWorkspace.Create(Panel2);
@@ -124,7 +138,9 @@ begin
 
     FWorkspace.OnMouseDown := WorkspaceMouseDown;
 
+    // Create and prepare the global scope once
     FGScope := TExecutionScope.Create(nil);
+    RegisterNativeFunctions(FGScope);
 end;
 
 procedure TForm1.DebugButtonClick(Sender: TObject);
@@ -137,7 +153,6 @@ begin
     if not Assigned(FLastAst) then
     begin
         Memo1.Lines.Add('No AST has been generated yet.');
-        Memo1.Lines.Add('Click "Test 1" or "Test 2" first.');
         exit;
     end;
 
@@ -146,7 +161,9 @@ begin
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Debug Evaluator Trace ---');
 
-    // This button ALWAYS uses the debug visitor, regardless of the checkbox.
+    // Manually bind and evaluate to use the debug visitor
+    TAst.Bind(FLastAst, scope);
+
     visitor := TDebugEvaluatorVisitor.Create(scope, Memo1.Lines, ShowScopeBox.IsChecked, 0);
 
     sw := TStopwatch.StartNew;
@@ -156,67 +173,18 @@ begin
     Memo1.Lines.Add('-----------------------------');
     Memo1.Lines.Add(Format('Final script result: %s', [result.ToString]));
     Memo1.Lines.Add(Format('Execution time: %d ms', [sw.ElapsedMilliseconds]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('(AST structure stored. Click "Pretty Print" to view.)');
 end;
 
 procedure TForm1.FibonacciButtonClick(Sender: TObject);
-
-    function NativeFib(n: Integer): Int64;
-    begin
-        // The identical, naive recursive algorithm in native Delphi code.
-        if (n < 2) then
-            Result := n
-        else
-            Result := NativeFib(n - 1) + NativeFib(n - 2);
-    end;
-
 var
-    scope: IExecutionScope;
-    visitor: IAstVisitor;
     root: IExpressionNode;
     result: TAstValue;
     sw: TStopwatch;
-    result20, result30, result40: Int64;
+    scope: IExecutionScope;
-    time20, time30, time40: Int64;
 begin
-    FGScope.Clear;
-
     Memo1.Lines.Clear;
-    Memo1.Lines.Add('--- Native Delphi Fibonacci Performance ---');
-    Memo1.Lines.Add('Calculating fib(30) and fib(40)...');
-    Application.ProcessMessages; // Update UI before blocking
-
-    // --- Calculate fib(30) ---
-    sw := TStopwatch.StartNew;
-    result20 := NativeFib(20);
-    sw.Stop;
-    time20 := sw.ElapsedMilliseconds;
-
-    // --- Calculate fib(30) ---
-    sw := TStopwatch.StartNew;
-    result30 := NativeFib(30);
-    sw.Stop;
-    time30 := sw.ElapsedMilliseconds;
-
-    // --- Calculate fib(40) ---
-    sw.Reset;
-    sw.Start;
-    result40 := NativeFib(40);
-    sw.Stop;
-    time40 := sw.ElapsedMilliseconds;
-    sw.Reset;
-
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add(Format('fib(20) = %d (calculated in %d ms)', [result20, time20]));
-    Memo1.Lines.Add(Format('fib(30) = %d (calculated in %d ms)', [result30, time30]));
-    Memo1.Lines.Add(Format('fib(40) = %d (calculated in %d ms)', [result40, time40]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('');
     Memo1.Lines.Add('--- Recursive fib with AST---');
-    Application.ProcessMessages; // Update UI before blocking
+    sw := TStopwatch.StartNew;
-
-    sw.Start;
 
     root :=
         TAst.Block(
@@ -225,12 +193,9 @@ begin
                     TAst.Identifier('fib'),
                     TAst.LambdaExpr(
                         [TAst.Identifier('n')],
-                        // The body is now a single ternary expression that returns a value.
                         TAst.TernaryExpr(
                             TAst.BinaryExpr(TAst.Identifier('n'), boLess, TAst.Constant(TScalar.FromInt64(2))),
-                            // The value if true.
                             TAst.Identifier('n'),
-                            // The value if false.
                             TAst.BinaryExpr(
                                 TAst.FunctionCall(
                                     TAst.Identifier('fib'),
@@ -250,21 +215,17 @@ begin
         );
 
     FLastAst := root;
-    scope := TExecutionScope.Create(nil);
+    scope := TExecutionScope.Create(nil); // No global scope needed for this pure function
+
+    result := ExecuteAst(root, scope);
 
-    visitor := CreateVisitor(scope);
-    result := root.Accept(visitor);
     sw.Stop;
-
     Memo1.Lines.Add(Format('Result: fib(30) %s (calculated in %d ms)', [result.ToString, sw.ElapsedMilliseconds]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('(AST structure stored. Click "Pretty Print" or "Debug" to view.)');
 end;
 
 procedure TForm1.PrettyPrintButtonClick(Sender: TObject);
 var
     visitor: TPrettyPrintVisitor;
-    sw: TStopwatch;
 begin
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- AST Pretty Print ---');
@@ -272,38 +233,24 @@ begin
     if not Assigned(FLastAst) then
     begin
         Memo1.Lines.Add('No AST has been generated yet.');
-        Memo1.Lines.Add('Click "Test 1" or "Test 2" first.');
         exit;
     end;
 
     visitor := TPrettyPrintVisitor.Create;
-    try
+    FLastAst.Accept(visitor);
-        sw := TStopwatch.StartNew;
+    Memo1.Lines.Add(visitor.GetResult);
-        FLastAst.Accept(visitor);
-        sw.Stop;
-
-        Memo1.Lines.Add(visitor.GetResult);
-        Memo1.Lines.Add(Format('(AST rendered in %d ms)', [sw.ElapsedMilliseconds]));
-    finally
-        // Visitor is an interfaced object and managed automatically.
-    end;
 end;
 
 procedure TForm1.RecursionButtonClick(Sender: TObject);
 var
-    scope: IExecutionScope;
-    visitor: IAstVisitor;
     root: IExpressionNode;
     result: TAstValue;
     sw: TStopwatch;
+    scope: IExecutionScope;
 begin
-    FGScope.Clear;
-
-    sw := TStopwatch.Create;
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Recursive factorial(20) ---');
-
+    sw := TStopwatch.StartNew;
-    sw.Start;
 
     root :=
         TAst.Block(
@@ -312,21 +259,17 @@ begin
                     TAst.Identifier('factorial'),
                     TAst.LambdaExpr(
                         [TAst.Identifier('n')],
-                        TAst.Block(
+                        TAst.TernaryExpr(
-                            [
+                            TAst.BinaryExpr(TAst.Identifier('n'), boLess, TAst.Constant(TScalar.FromInt64(2))),
-                                TAst.TernaryExpr(
+                            TAst.Constant(TScalar.FromInt64(1)),
-                                    TAst.BinaryExpr(TAst.Identifier('n'), boLess, TAst.Constant(TScalar.FromInt64(2))),
+                            TAst.BinaryExpr(
-                                    TAst.Constant(TScalar.FromInt64(1)),
+                                TAst.Identifier('n'),
-                                    TAst.BinaryExpr(
+                                boMultiply,
-                                        TAst.Identifier('n'),
+                                TAst.FunctionCall(
-                                        boMultiply,
+                                    TAst.Identifier('factorial'),
-                                        TAst.FunctionCall(
+                                    [TAst.BinaryExpr(TAst.Identifier('n'), boSubtract, TAst.Constant(TScalar.FromInt64(1)))]
-                                            TAst.Identifier('factorial'),
-                                            [TAst.BinaryExpr(TAst.Identifier('n'), boSubtract, TAst.Constant(TScalar.FromInt64(1)))]
-                                        )
-                                    )
                                 )
-                            ]
+                            )
                         )
                     )
                 ),
@@ -337,43 +280,31 @@ begin
     FLastAst := root;
     scope := TExecutionScope.Create(nil);
 
-    visitor := CreateVisitor(scope);
+    result := ExecuteAst(root, scope);
-    result := root.Accept(visitor);
-    sw.Stop;
 
+    sw.Stop;
     Memo1.Lines.Add(Format('Result: %s (calculated in %d ms)', [result.ToString, sw.ElapsedMilliseconds]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('(AST structure stored. Click "Pretty Print" or "Debug" to view.)');
 end;
 
 procedure TForm1.SeriesTestButtonClick(Sender: TObject);
 var
-    jsonDef: string;
+    scope: IExecutionScope;
-    recordDef: TScalarRecordDefinition;
+    ast, callAst: IExpressionNode;
-    series: TScalarRecordSeries;
-    recordValue: TScalarRecord;
-    visitor: IAstVisitor;
-    ast: IExpressionNode;
     resultValue: TAstValue;
+    series: TScalarRecordSeries;
+    recordDef: TScalarRecordDefinition;
     i: Integer;
 begin
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Series Test ---');
 
-    // --- 1. Arrange (in Delphi) ---
+    // 1. Arrange: Create a new scope and populate it with Delphi data
-    Memo1.Lines.Add('1. Arranging test data in Delphi...');
+    scope := TExecutionScope.Create(FGScope); // Inherits native functions
-    FGScope.Clear;
+    recordDef := TRttiAstHelper.JsonToRecordDefinition(TRttiAstHelper.RecordDefinitionToJson(TypeInfo(TOHLCV)));
-    RegisterNativeFunctions(FGScope);
-
-    jsonDef := TRttiAstHelper.RecordDefinitionToJson(TypeInfo(TOHLCV));
-    FGScope.SetValue('ohlcvDef', TAstValue.FromText(jsonDef));
-    Memo1.Lines.Add('   - Generated and injected JSON definition for TOHLCV.');
-
-    recordDef := TRttiAstHelper.JsonToRecordDefinition(jsonDef);
     series := TScalarRecordSeries.Create(recordDef);
     for i := 0 to 4 do
     begin
-        recordValue :=
+        series.Add(
             TScalarRecord.Create(
                 recordDef,
                 [
@@ -384,17 +315,12 @@ begin
                     TScalarValue.FromDouble(102.0 + i),
                     TScalarValue.FromInt64(10000 * (i + 1))
                 ]
-            );
+            )
-        series.Add(recordValue);
+        );
     end;
+    scope.Define('ohlcvSeries', TAstValue.FromRecordSeries(series));
 
-    FGScope.SetValue('ohlcvSeries', TAstValue.FromRecordSeries(series));
+    // 2. Act: Define and execute the script AST
-    Memo1.Lines.Add(Format('   - Created and injected a series with %d records.', [series.TotalCount]));
-    Memo1.Lines.Add('');
-
-    // --- 2. Act (in Script) ---
-    Memo1.Lines.Add('2. Executing script...');
-
     ast :=
         TAst.LambdaExpr(
             [],
@@ -404,69 +330,31 @@ begin
                         TAst.Identifier('closeColumn'),
                         TAst.MemberAccess(TAst.Identifier('ohlcvSeries'), TAst.Identifier('Close'))
                     ),
-                    TAst.VarDecl(
+                    TAst.Indexer(TAst.Identifier('closeColumn'), TAst.Constant(TScalar.FromInt64(1)))
-                        TAst.Identifier('secondClose'),
-                        TAst.Indexer(TAst.Identifier('closeColumn'), TAst.Constant(TScalar.FromInt64(1)))
-                    )
                 ]
             )
         );
+
     FLastAst := ast;
+    callAst := TAst.FunctionCall(ast, []);
+    resultValue := ExecuteAst(callAst, scope);
 
-    visitor := CreateVisitor(FGScope);
+    // 3. Assert (logging only)
-    resultValue := TAst.FunctionCall(ast, []).Accept(visitor);
+    Memo1.Lines.Add(Format('Result of script: %s', [resultValue.ToString]));
-
-    Memo1.Lines.Add('   - Script finished.');
-    Memo1.Lines.Add(Format('   - Script returned value of type: %s', [GetEnumName(TypeInfo(TAstValueKind), Ord(resultValue.Kind))]));
-    Memo1.Lines.Add('');
-
-    // --- 3. Assert (in Delphi) ---
-    Memo1.Lines.Add('3. Asserting results in Delphi...');
-
-    if (resultValue.Kind <> avkScalar) then
-    begin
-        Memo1.Lines.Add('TEST FAILED: Script did not return a scalar value.');
-        exit;
-    end;
-    Memo1.Lines.Add('   - Result is a scalar, as expected.');
-
-    var resultScalar := resultValue.AsScalar;
-    if (resultScalar.Kind <> skDouble) then
-    begin
-        Memo1.Lines.Add('TEST FAILED: Returned scalar is not a Double.');
-        exit;
-    end;
-    Memo1.Lines.Add('   - Returned scalar is a Double, as expected.');
-
-    var closeValue := resultScalar.Value.AsDouble;
-    // The script asks for index [1], which is the second-to-last element.
-    // The data was generated for i in 0..4, so the second-to-last is i=3.
-    var expectedClose := 102.0 + 3;
-    if (abs(closeValue - expectedClose) > 0.001) then
-    begin
-        Memo1.Lines.Add(Format('TEST FAILED: Expected Close price %f, but got %f.', [expectedClose, closeValue]));
-        exit;
-    end;
-    Memo1.Lines.Add(Format('   - Verified Close price: %f.', [closeValue]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('--- TEST PASSED ---');
 end;
 
 procedure TForm1.Test1ButtonClick(Sender: TObject);
 var
-    scope: IExecutionScope;
+    main, callAst: IExpressionNode;
-    visitor: IAstVisitor;
     result: TAstValue;
     sw: TStopwatch;
+    scope: IExecutionScope;
 begin
-    FGScope.Clear;
-
-    sw := TStopwatch.Create;
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Simple AST Execution ---');
+    sw := TStopwatch.StartNew;
 
-    sw.Start;
+    main :=
-    var main :=
         TAst.LambdaExpr(
             [],
             TAst.Block(
@@ -482,35 +370,25 @@ begin
         );
 
     FLastAst := main;
+    callAst := TAst.FunctionCall(main, []);
     scope := TExecutionScope.Create(FGScope);
 
-    visitor := CreateVisitor(scope);
+    result := ExecuteAst(callAst, scope);
-    result := TAst.FunctionCall(main, []).Accept(visitor);
-    sw.Stop;
 
-    if not result.IsVoid then
+    sw.Stop;
-        Memo1.Lines.Add(Format('Result: %s (calculated in %d ms)', [result.ToString, sw.ElapsedMilliseconds]))
+    Memo1.Lines.Add(Format('Result: %s (calculated in %d ms)', [result.ToString, sw.ElapsedMilliseconds]));
-    else
-        Memo1.Lines.Add(Format('<undefined result> (calculated in %d ms)', [sw.ElapsedMilliseconds]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('(AST structure stored. Click "Pretty Print" to view.)');
 end;
 
 procedure TForm1.Test2ButtonClick(Sender: TObject);
 var
-    scope: IExecutionScope;
-    visitor: IAstVisitor;
     root: IExpressionNode;
     result: TAstValue;
     sw: TStopwatch;
+    scope: IExecutionScope;
 begin
-    FGScope.Clear;
-
-    sw := TStopwatch.Create;
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Factory Pattern Demo ---');
-
+    sw := TStopwatch.StartNew;
-    sw.Start;
 
     root :=
         TAst.Block(
@@ -533,34 +411,26 @@ begin
         );
 
     FLastAst := root;
-
     scope := TExecutionScope.Create(FGScope);
 
-    visitor := CreateVisitor(scope);
+    result := ExecuteAst(root, scope);
-    result := root.Accept(visitor);
-    sw.Stop;
 
-    Memo1.Lines.Add('The entire script has been executed.');
+    sw.Stop;
     Memo1.Lines.Add(Format('Result of the final expression: %s (calculated in %d ms)', [result.ToString, sw.ElapsedMilliseconds]));
-    Memo1.Lines.Add('');
-    Memo1.Lines.Add('(AST structure stored. Click "Pretty Print" to view.)');
 end;
 
 procedure TForm1.CrerateTriggerExampleButtonClick(Sender: TObject);
 var
-    visitor: IAstVisitor;
+    blk: IExpressionNode;
-    closureValue: TAstValue;
 begin
+    // This button now only creates the AST. The persistent scope is managed by FGScope.
     FGScope.Clear;
-
+    RegisterNativeFunctions(FGScope); // Re-register natives after clearing
-    // Create an AST that gets a "tick" in DoTriggerButtonClick.
-    // This simulates a simple Blueprint-like event system.
-    // It maintains state via a persistent execution scope.
 
     Memo1.Lines.Clear;
     Memo1.Lines.Add('--- Creating Trigger Blueprint ---');
 
-    var blk :=
+    blk :=
         TAst.Block(
             [
                 TAst.VarDecl(TAst.Identifier('X'), TAst.Constant(TScalar.FromInt64(0))),
@@ -574,77 +444,65 @@ begin
             ]
         );
 
-    // Evaluate the lambda to create a closure and store it in the scope.
+    // Bind and execute the setup block against the persistent global scope
-    // The closure captures the scope where 'X' is defined.
+    ExecuteAst(blk, FGScope);
-    visitor := CreateVisitor(FGScope);
-    blk.Accept(visitor);
 
-    // FLastAst is not used for this parameterized example.
+    FLastAst := blk; // Store for visualization
-    FLastAst := blk;
 
-    Memo1.Lines.Add('Variable "X" initialized to 0 in persistent scope.');
+    Memo1.Lines.Add('Variable "X" and function "tickHandler" defined in persistent scope.');
-    Memo1.Lines.Add('Blueprint function "tickHandler(summand)" created.');
+    Memo1.Lines.Add('Click "Do Trigger" to execute.');
-    Memo1.Lines.Add('Click "Do Trigger" or "Do Trigger 2" to execute.');
 end;
 
 procedure TForm1.DoTriggerButtonClick(Sender: TObject);
 var
-    visitor: IAstVisitor;
-    currentValue: TAstValue;
     callAst: IFunctionCallNode;
+    currentValue: TAstValue;
+    depth, index: Integer;
+    identAst: IIdentifierNode;
 begin
-    // A "tick" executes the stored AST using the persistent scope.
-
-    // Create an AST to call the stored handler with argument 1.
-    // AST for: tickHandler(1)
     callAst := TAst.FunctionCall(TAst.Identifier('tickHandler'), [TAst.Constant(TScalar.FromInt64(1))]);
-
-    // Execute the call AST.
-    visitor := CreateVisitor(FGScope);
-    callAst.Accept(visitor);
-
     FLastAst := callAst;
 
-    // Get the updated value of 'X' from the scope and display it.
+    // Bind and execute the call against the persistent scope
-    if FGScope.FindValue('X', currentValue) then
+    ExecuteAst(callAst, FGScope);
+
+    // To get the value of 'X', we first need to bind an identifier for it
+    // so we know its location.
+    identAst := TAst.Identifier('X');
+    TAst.Bind(identAst, FGScope);
+
+    if identAst.Resolve(depth, index) then
     begin
+        currentValue := FGScope.GetValue(depth, index);
         Memo1.Lines.Add(Format('Tick(1)! New value of X: %s', [currentValue.ToString]));
     end
     else
-    begin
-        // This should not happen if setup was correct.
         Memo1.Lines.Add('Error: Variable "X" not found in scope.');
-    end;
 end;
 
 procedure TForm1.DoTrigger2ButtonClick(Sender: TObject);
 var
-    visitor: IAstVisitor;
-    currentValue: TAstValue;
     callAst: IFunctionCallNode;
+    currentValue: TAstValue;
+    depth, index: Integer;
+    identAst: IIdentifierNode;
 begin
-    // A "tick" that adds 2, using the same blueprint function.
-
-    // Create an AST to call the stored handler with argument 2.
-    // AST for: tickHandler(2)
     callAst := TAst.FunctionCall(TAst.Identifier('tickHandler'), [TAst.Constant(TScalar.FromInt64(2))]);
-
     FLastAst := callAst;
 
-    // Execute the call AST.
+    // Bind and execute the call against the persistent scope
-    visitor := CreateVisitor(FGScope);
+    ExecuteAst(callAst, FGScope);
-    callAst.Accept(visitor);
 
-    // Get the updated value of 'X' from the scope and display it.
+    // Inspection requires binding an identifier for 'X'
-    if FGScope.FindValue('X', currentValue) then
+    identAst := TAst.Identifier('X');
+    TAst.Bind(identAst, FGScope);
+    if identAst.Resolve(depth, index) then
     begin
+        currentValue := FGScope.GetValue(depth, index);
         Memo1.Lines.Add(Format('Tick(2)! New value of X: %s', [currentValue.ToString]));
     end
     else
-    begin
-        // This should not happen if setup was correct.
         Memo1.Lines.Add('Error: Variable "X" not found in scope.');
-    end;
 end;
 
 procedure TForm1.WorkspaceMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
@@ -663,22 +521,22 @@ end;
 
 procedure TForm1.OHLCButtonClick(Sender: TObject);
 const
-    numRecs = 1000;
+    numRecs = 1000000;
-    lookback = 50;
+    lookback = 100;
-    smaSlowLength = 20;
+    smaSlowLength = 50;
-    smaFastLength = 5;
+    smaFastLength = 20;
 var
     recordDef: TScalarRecordDefinition;
     series: TScalarRecordSeries;
-    setupAst: IExpressionNode;
+    setupAst, callAst: IExpressionNode;
-    callAst: IExpressionNode;
     visitor: IAstVisitor;
-    i: Integer;
+    i, depth, index: Integer;
     lastClose: Double;
     ohlcvRec: TOHLCV;
     recordValue: TScalarRecord;
     resultValue: TAstValue;
     sw: TStopwatch;
+    currentSeriesIdent: IIdentifierNode;
 begin
     // 1. Setup
     Memo1.Lines.Clear;
@@ -687,14 +545,10 @@ begin
     RegisterNativeFunctions(FGScope);
     sw := TStopwatch.StartNew;
 
-    recordDef := TRttiAstHelper.JsonToRecordDefinition(TRttiAstHelper.RecordDefinitionToJson(TypeInfo(TOHLCV)));
+    // 2. Create the setup AST with the strategy logic
-    series := TScalarRecordSeries.Create(recordDef);
-
-    // 2. Create the setup AST with the optimized O(1) SMA implementation
     setupAst :=
         TAst.Block(
             [
-                // This factory is now much simpler. It only manages sum and a counter.
                 TAst.VarDecl(
                     TAst.Identifier('CreateSMA'),
                     TAst.LambdaExpr(
@@ -703,7 +557,6 @@ begin
                             [
                                 TAst.VarDecl(TAst.Identifier('sum'), TAst.Constant(TScalar.FromDouble(0.0))),
                                 TAst.VarDecl(TAst.Identifier('count'), TAst.Constant(TScalar.FromInt64(0))),
-                                // The returned closure now takes the full series and the new value.
                                 TAst.LambdaExpr(
                                     [TAst.Identifier('series'), TAst.Identifier('val')],
                                     TAst.Block(
@@ -716,7 +569,6 @@ begin
                                                 TAst.Identifier('count'),
                                                 TAst.BinaryExpr(TAst.Identifier('count'), boAdd, TAst.Constant(TScalar.FromInt64(1)))
                                             ),
-                                            // If the indicator is "full", subtract the value that just fell out of the window (at index 'len').
                                             TAst.IfExpr(
                                                 TAst.BinaryExpr(TAst.Identifier('count'), boGreater, TAst.Identifier('len')),
                                                 TAst.Assign(
@@ -729,7 +581,6 @@ begin
                                                 ),
                                                 nil
                                             ),
-                                            // Calculate and return the average. Divisor is capped at 'len'.
                                             TAst.BinaryExpr(
                                                 TAst.Identifier('sum'),
                                                 boDivide,
@@ -746,7 +597,6 @@ begin
                         )
                     )
                 ),
-                // Instantiation remains the same.
                 TAst.VarDecl(
                     TAst.Identifier('smaFast'),
                     TAst.FunctionCall(TAst.Identifier('CreateSMA'), [TAst.Constant(TScalar.FromInt64(smaFastLength))])
@@ -755,7 +605,6 @@ begin
                     TAst.Identifier('smaSlow'),
                     TAst.FunctionCall(TAst.Identifier('CreateSMA'), [TAst.Constant(TScalar.FromInt64(smaSlowLength))])
                 ),
-                // The main strategy now passes the full close series to the indicators.
                 TAst.VarDecl(
                     TAst.Identifier('maCrossStrategy'),
                     TAst.LambdaExpr(
@@ -795,13 +644,30 @@ begin
                 )
             ]
         );
-
     FLastAst := setupAst;
-    visitor := CreateVisitor(FGScope);
+    // Bind and execute the setup script once.
-    setupAst.Accept(visitor);
+    ExecuteAst(setupAst, FGScope);
-    callAst := TAst.FunctionCall(TAst.Identifier('maCrossStrategy'), [TAst.Identifier('current_series')]);
 
-    // 3. Simulation Loop
+    // 3. Prepare for the simulation loop
+    recordDef := TRttiAstHelper.JsonToRecordDefinition(TRttiAstHelper.RecordDefinitionToJson(TypeInfo(TOHLCV)));
+    series := TScalarRecordSeries.Create(recordDef);
+    visitor := CreateVisitor(FGScope);
+
+    // Declare the series variable in the scope BEFORE binding the call AST
+    FGScope.Define('current_series', TAstValue.Void);
+
+    // Create the call AST that will be executed in the loop
+    currentSeriesIdent := TAst.Identifier('current_series');
+    callAst := TAst.FunctionCall(TAst.Identifier('maCrossStrategy'), [currentSeriesIdent]);
+
+    // Bind the call AST once, before the loop.
+    TAst.Bind(callAst, FGScope);
+
+    // Get the resolved address of 'current_series' for fast updates
+    if not currentSeriesIdent.Resolve(depth, index) then
+        raise EInvalidOpException.Create('Could not resolve loop variable ''current_series''.');
+
+    // 4. Simulation Loop
     Memo1.Lines.Add('Starting simulation...');
     Application.ProcessMessages;
 
@@ -836,11 +702,14 @@ begin
 
         if series.TotalCount >= smaSlowLength then
         begin
-            FGScope.SetValue('current_series', TAstValue.FromRecordSeries(series));
+            // Update the 'current_series' value in the scope using the FAST index-based assignment
+            FGScope.AssignValue(depth, index, TAstValue.FromRecordSeries(series));
+
+            // Execute the PRE-BOUND call AST
             resultValue := callAst.Accept(visitor);
 
-            Memo1.Lines.Add(Format('Tick %d/%d: Close = %.2f, Signal = %s', [i, numRecs, ohlcvRec.Close, resultValue.ToString]));
+            //            Memo1.Lines.Add(Format('Tick %d/%d: Close = %.2f, Signal = %s', [i, numRecs, ohlcvRec.Close, resultValue.ToString]));
-            Application.ProcessMessages;
+            //            Application.ProcessMessages;
         end;
     end;
 

Src/AST/Myc.Ast.Evaluator.pas

@@ -35,7 +35,7 @@ type
         function VisitMemberAccess(const Node: IMemberAccessNode): TAstValue; virtual;
         function VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue; virtual;
         function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue; virtual;
-        function VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
+        function VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue; virtual;
     end;
 
     // TDebugEvaluatorVisitor now overrides all visit methods for full tracing
@@ -68,6 +68,7 @@ type
         function VisitMemberAccess(const Node: IMemberAccessNode): TAstValue; override;
         function VisitCreateSeries(const Node: ICreateSeriesNode): TAstValue; override;
         function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue; override;
+        function VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue; override;
     end;
 
 // Registers all native core functions in the given scope.
@@ -81,7 +82,7 @@ uses
     Myc.Data.Series,
     Myc.Ast.Scope,
     Myc.Ast.Printer,
-    Myc.Data.Scalar.JSON; // Added for JsonToRecordDefinition
+    Myc.Data.Scalar.JSON;
 
 type
     // The signature for a native Delphi function callable from the script.
@@ -194,9 +195,10 @@ procedure RegisterNativeFunctions(const AScope: IExecutionScope);
 var
     closure: IEvaluatorClosure;
 begin
-    // Register CreateRecordSeries
+    // Use 'Define' to clearly state that we are adding a new variable
+    // to the global scope before the binder runs.
     closure := TNativeClosure.Create(NativeCreateRecordSeries);
-    AScope.SetValue('CreateRecordSeries', TAstValue.FromClosure(closure));
+    AScope.Define('CreateRecordSeries', TAstValue.FromClosure(closure));
 end;
 
 { TClosureValue }
@@ -280,19 +282,19 @@ end;
 
 function TEvaluatorVisitor.VisitAddSeriesItem(const Node: IAddSeriesItemNode): TAstValue;
 var
-    itemValue, lookbackValue: TAstValue;
+    itemValue, lookbackValue, seriesVar: TAstValue;
     lookback: Int64;
-    varName: string;
+    depth, index: Integer;
-    seriesVar: TAstValue;
 begin
-    // The target series is now guaranteed to be an identifier by the AST node definition.
+    // The target series must have been resolved by the binder.
-    varName := Node.Series.Name;
+    if not Node.Series.Resolve(depth, index) then
-    if not FScope.FindValue(varName, seriesVar) then
+        raise EArgumentException
-        raise EArgumentException.CreateFmt('Identifier not found: "%s"', [varName]);
+            .CreateFmt('Identifier could not be resolved: "%s". This should have been caught by the binder.', [Node.Series.Name]);
 
+    seriesVar := FScope.GetValue(depth, index);
     itemValue := Node.Value.Accept(Self);
+    lookback := -1;
 
-    lookback := -1; // Default: no lookback limit
     if Assigned(Node.Lookback) then
     begin
         lookbackValue := Node.Lookback.Accept(Self);
@@ -335,22 +337,20 @@ begin
     else
         raise EArgumentException.Create('"add" operation is only supported for series types.');
     end;
-    Result := TAstValue.Void;
 end;
 
 function TEvaluatorVisitor.VisitAssignment(const Node: IAssignmentNode): TAstValue;
 var
-    varName: string;
     value: TAstValue;
+    depth, index: Integer;
 begin
-    // Evaluate the right-hand side of the assignment.
     value := Node.Value.Accept(Self);
-    varName := Node.Identifier.Name;
 
-    // Assign the value to the variable in the scope chain.
+    if not Node.Identifier.Resolve(depth, index) then
-    FScope.AssignValue(varName, value);
+        raise EArgumentException
+            .CreateFmt('Identifier could not be resolved: "%s". This should have been caught by the binder.', [Node.Identifier.Name]);
 
-    // Assignment expressions return the assigned value.
+    FScope.AssignValue(depth, index, value);
     Result := value;
 end;
 
@@ -365,10 +365,8 @@ var
 begin
     def := Node.Definition.Trim;
 
-    // Based on the content, create a scalar or a record series.
     if def.StartsWith('[') then
     begin
-        // Assumed to be a record definition array, e.g., '[{"Name": "Close", "Kind": "skDouble"}]'
         var recordDef := TRttiAstHelper.JsonToRecordDefinition(def);
         if Length(recordDef.Fields) = 0 then
             raise EArgumentException.Create('Failed to parse record definition from JSON array.');
@@ -378,7 +376,6 @@ begin
     end
     else
     begin
-        // Assumed to be a single scalar type name, e.g., 'double'
         var scalarKind := StringToScalarKind(def);
         var scalarSeries := TScalarSeries.Create(scalarKind, Default(TSeries<TScalarValue>));
         Result := TAstValue.FromSeries(scalarSeries);
@@ -387,12 +384,14 @@ end;
 
 function TEvaluatorVisitor.VisitIdentifier(const Node: IIdentifierNode): TAstValue;
 var
-    val: TAstValue;
+    depth, index: Integer;
 begin
-    if FScope.FindValue(Node.Name, val) then
+    if Node.Resolve(depth, index) then
-        Result := val
+        Result := FScope.GetValue(depth, index)
     else
-        raise EArgumentException.CreateFmt('Identifier not found: "%s"', [Node.Name]);
+        // This should not happen if the binder ran successfully.
+        raise EArgumentException
+            .CreateFmt('Identifier could not be resolved: "%s". This should have been caught by the binder.', [Node.Name]);
 end;
 
 function TEvaluatorVisitor.VisitIndexer(const Node: IIndexerNode): TAstValue;
@@ -404,7 +403,6 @@ begin
     baseValue := Node.Base.Accept(Self);
     indexValue := Node.Index.Accept(Self);
 
-    // Index validation (common for all indexable types)
     if (indexValue.Kind <> avkScalar) then
         raise EArgumentException.Create('Indexer `[]` requires a scalar integer argument.');
 
@@ -416,7 +414,6 @@ begin
         raise EArgumentException.Create('Indexer `[]` requires an integer type argument.');
     end;
 
-    // Base type dispatching
     case baseValue.Kind of
         avkSeries:
         begin
@@ -484,14 +481,15 @@ end;
 
 function TEvaluatorVisitor.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
 var
-    varName: string;
+    value: TAstValue;
 begin
-    varName := Node.Identifier.Name;
     if Assigned(Node.Initializer) then
-        Result := Node.Initializer.Accept(Self)
+        value := Node.Initializer.Accept(Self)
     else
-        Result := TAstValue.Void;
+        value := TAstValue.Void;
-    FScope.SetValue(varName, Result);
+
+    FScope.Define(Node.Identifier.Name, value);
+    Result := value;
 end;
 
 function TEvaluatorVisitor.VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue;
@@ -518,10 +516,8 @@ begin
 
     closure := calleeValue.AsClosure;
 
-    // Distinguish between native and script-defined closures.
     if closure is TNativeClosure then
     begin
-        // Native function call
         SetLength(argValues, Node.Arguments.Count);
         for i := 0 to Node.Arguments.Count - 1 do
         begin
@@ -531,23 +527,25 @@ begin
     end
     else if closure is TClosureValue then
     begin
-        // Script function call (original logic)
         if (Node.Arguments.Count <> Length(closure.Parameters)) then
             raise EArgumentException
                 .CreateFmt('Argument count mismatch: expected %d, got %d', [Length(closure.Parameters), Node.Arguments.Count]);
 
         callScope := TExecutionScope.Create(closure.ClosureScope);
 
+        // The order of definitions must exactly match the binder's order.
+
+        // Define 'Self' first.
+        callScope.Define('Self', calleeValue);
+
+        // 2. Then, define the parameters.
         for i := 0 to Node.Arguments.Count - 1 do
         begin
-            argValues := [Node.Arguments[i].Accept(Self)];
+            var argValue := Node.Arguments[i].Accept(Self);
-            callScope.SetValue(closure.Parameters[i].Name, argValues[0]);
+            callScope.Define(closure.Parameters[i].Name, argValue);
         end;
 
         innerVisitor := Self.CreateVisitorForScope(callScope);
-
-        callScope.SetValue('Self', calleeValue);
-        callScope.SetValue('Result', TAstValue.Void);
         Result := closure.Body.Accept(innerVisitor);
     end
     else
@@ -559,7 +557,6 @@ var
     leftValue, rightValue: TAstValue;
     leftScalar, rightScalar: TScalar;
 begin
-    // Implemented binary operators for Int64 and Double.
     leftValue := Node.Left.Accept(Self);
     rightValue := Node.Right.Accept(Self);
 
@@ -571,7 +568,6 @@ begin
 
     if (leftScalar.Kind <> rightScalar.Kind) then
     begin
-        // Automatic type promotion from Int64 to Double.
         if (leftScalar.Kind = skInt64) and (rightScalar.Kind = skDouble) then
         begin
             leftScalar := TScalar.FromDouble(leftScalar.Value.AsInt64);
@@ -582,7 +578,6 @@ begin
         end
         else
         begin
-            // If types are still different after promotion, they are incompatible.
             raise ENotSupportedException.Create(
                 'Binary operations are only supported for compatible types. ' + leftScalar.ToString + '  ' + rightScalar.ToString);
         end;
@@ -637,7 +632,6 @@ var
     rightValue: TAstValue;
     rightScalar: TScalar;
 begin
-    // Implemented unary operators for Int64, Double, and Boolean.
     rightValue := Node.Right.Accept(Self);
 
     case Node.Operator of
@@ -655,7 +649,6 @@ begin
         end;
         uoNot:
         begin
-            // "not" operates on the truthiness of the value.
             Result := TAstValue.FromScalar(TScalar.FromBoolean(not IsTruthy(rightValue)));
         end;
     else
@@ -672,11 +665,9 @@ begin
         Result := Node.ThenBranch.Accept(Self)
     else
     begin
-        // If an else branch exists, evaluate it.
         if Assigned(Node.ElseBranch) then
             Result := Node.ElseBranch.Accept(Self)
         else
-            // Otherwise, an if-statement without an else branch evaluates to void.
             Result := TAstValue.Void;
     end;
 end;
@@ -695,14 +686,13 @@ end;
 function TEvaluatorVisitor.VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
 var
     expression: IExpressionNode;
-    lastValue: TAstValue;
 begin
-    lastValue := TAstValue.Void;
+    // The result of a block is the result of its last expression.
+    Result := TAstValue.Void;
     for expression in Node.Expressions do
     begin
-        lastValue := expression.Accept(Self);
+        Result := expression.Accept(Self);
     end;
-    Result := lastValue;
 end;
 
 function TEvaluatorVisitor.VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
@@ -710,20 +700,16 @@ var
     seriesValue: TAstValue;
     len: Int64;
 begin
-    // 1. Evaluate the identifier to get the series object from the scope.
     seriesValue := Node.Series.Accept(Self);
 
-    // 2. Get the length based on the actual series type.
     case seriesValue.Kind of
         avkSeries: len := seriesValue.AsSeries.Value.Items.Count;
         avkRecordSeries: len := seriesValue.AsRecordSeries.Value.Count;
         avkMemberSeries: len := seriesValue.AsMemberSeries.Value.Count;
     else
-        // It's an error if we try to get the length of something that isn't a series.
         raise EArgumentException.CreateFmt('Cannot get length of type %s.', [GetEnumName(TypeInfo(TAstValueKind), Ord(seriesValue.Kind))]);
     end;
 
-    // 3. Return the length as a new scalar value.
     Result := TAstValue.FromScalar(TScalar.FromInt64(len));
 end;
 
@@ -811,7 +797,8 @@ end;
 
 function TDebugEvaluatorVisitor.VisitAssignment(const Node: IAssignmentNode): TAstValue;
 begin
-    AppendLine(Format('Assignment %s := {', [Node.Identifier.Name]));
+    // The name is not easily available anymore for logging.
+    AppendLine(Format('Assignment to "%s" {', [Node.Identifier.Name]));
     Indent;
     try
         Result := inherited VisitAssignment(Node);
@@ -970,4 +957,16 @@ begin
     end;
 end;
 
+function TDebugEvaluatorVisitor.VisitSeriesLength(const Node: ISeriesLengthNode): TAstValue;
+begin
+    AppendLine('SeriesLength {');
+    Indent;
+    try
+        Result := inherited VisitSeriesLength(Node);
+    finally
+        Unindent;
+    end;
+    AppendLine(Format('} -> %s', [Result.ToString]));
+end;
+
 end.

Src/AST/Myc.Ast.Nodes.pas

@@ -101,9 +101,20 @@ type
         function GetParent: IExecutionScope;
         {$endregion}
         procedure Clear;
-        function FindValue(const Name: string; out Value: TAstValue): Boolean;
+
-        procedure SetValue(const Name: string; const Value: TAstValue);
+        // --- Legacy name-based access (for pre-binder setup, e.g., native functions) ---
-        procedure AssignValue(const Name: string; const Value: TAstValue);
+        function FindValue(const Name: string; out Value: TAstValue): Boolean; deprecated 'Use index-based access after binding.';
+        procedure SetValue(const Name: string; const Value: TAstValue); deprecated 'Use Define for script variables.';
+        procedure AssignValue(const Name: string; const Value: TAstValue); overload; deprecated 'Use index-based assignment after binding.';
+
+        // --- New index-based access (for use by the evaluator after binding) ---
+        // Defines a new variable in the current scope.
+        procedure Define(const Name: string; const Value: TAstValue);
+        // Gets a value from a scope at a specific depth and slot index.
+        function GetValue(Depth, Index: Integer): TAstValue;
+        // Assigns a new value to an existing variable at a specific depth and slot index.
+        procedure AssignValue(Depth, Index: Integer; const Value: TAstValue); overload;
+
         function Dump: string;
         property Parent: IExecutionScope read GetParent;
     end;

Src/AST/Myc.Ast.Scope.pas

@@ -12,7 +12,8 @@ type
     TExecutionScope = class(TInterfacedObject, IExecutionScope)
     private
         FParent: IExecutionScope;
-        FVariables: TDictionary<string, TAstValue>;
+        FValues: TArray<TAstValue>;
+        FNameToIndex: TDictionary<string, Integer>;
         procedure DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
     protected
         // IExecutionScope
@@ -20,27 +21,37 @@ type
         procedure Clear;
         function FindValue(const Name: string; out Value: TAstValue): Boolean;
         procedure SetValue(const Name: string; const Value: TAstValue);
-        procedure AssignValue(const Name: string; const Value: TAstValue);
+        procedure AssignValue(const Name: string; const Value: TAstValue); overload;
         function Dump: string;
+
+        // --- New index-based access methods ---
+        procedure Define(const Name: string; const Value: TAstValue);
+        function GetValue(Depth, Index: Integer): TAstValue;
+        procedure AssignValue(Depth, Index: Integer; const Value: TAstValue); overload;
     public
         constructor Create(AParent: IExecutionScope = nil);
         destructor Destroy; override;
+        property NameToIndex: TDictionary<string, Integer> read FNameToIndex;
     end;
 
 implementation
 
+uses
+    System.Generics.Defaults; // For TComparer
+
 { TExecutionScope }
 
 constructor TExecutionScope.Create(AParent: IExecutionScope);
 begin
     inherited Create;
     FParent := AParent;
-    FVariables := TDictionary<string, TAstValue>.Create;
+    FValues := [];
+    FNameToIndex := TDictionary<string, Integer>.Create;
 end;
 
 destructor TExecutionScope.Destroy;
 begin
-    FVariables.Free;
+    FNameToIndex.Free;
     inherited Destroy;
 end;
 
@@ -50,32 +61,75 @@ begin
 end;
 
 procedure TExecutionScope.AssignValue(const Name: string; const Value: TAstValue);
+var
+    index: Integer;
 begin
-    if FVariables.ContainsKey(Name) then
+    if FNameToIndex.TryGetValue(Name, index) then
-        FVariables.AddOrSetValue(Name, Value)
+        FValues[index] := Value
     else if Assigned(FParent) then
         FParent.AssignValue(Name, Value)
     else
         raise Exception.CreateFmt('Cannot assign to undeclared variable "%s".', [Name]);
 end;
 
+procedure TExecutionScope.AssignValue(Depth, Index: Integer; const Value: TAstValue);
+var
+    targetScope: IExecutionScope;
+    i: Integer;
+begin
+    targetScope := Self;
+    for i := 1 to Depth do
+    begin
+        if Assigned(targetScope) then
+            targetScope := targetScope.Parent
+        else
+            // This should not happen if the binder works correctly.
+            raise EInvalidOpException.Create('Invalid scope depth during assignment.');
+    end;
+
+    // We must cast back to the implementation to modify the private array.
+    (targetScope as TExecutionScope).FValues[Index] := Value;
+end;
+
 procedure TExecutionScope.Clear;
 begin
-    FVariables.Clear;
+    FValues := [];
-    if Assigned(FParent) then
+    FNameToIndex.Clear;
-        FParent.Clear;
+end;
+
+procedure TExecutionScope.Define(const Name: string; const Value: TAstValue);
+var
+    index: Integer;
+begin
+    // A variable can only be defined once per scope.
+    if FNameToIndex.ContainsKey(Name) then
+        raise Exception.CreateFmt('Variable "%s" is already defined in this scope.', [Name]);
+
+    index := Length(FValues);
+    SetLength(FValues, index + 1);
+    FValues[index] := Value;
+    FNameToIndex.Add(Name, index);
 end;
 
 procedure TExecutionScope.DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
 var
-    pair: TPair<string, TAstValue>;
+    pair: TPair<string, Integer>;
     indentStr: string;
+    sortedPairs: TArray<TPair<string, Integer>>;
 begin
     indentStr := ''.PadLeft(AIndent);
-    if (FVariables.Count > 0) then
+    if (FNameToIndex.Count > 0) then
     begin
-        for pair in FVariables do
+        // Copy pairs to an array and sort it by index for consistent output
-            ABuilder.AppendLine(indentStr + Format('  %s: %s', [pair.Key, pair.Value.ToString]));
+        sortedPairs := FNameToIndex.ToArray;
+        TArray.Sort<TPair<string, Integer>>(
+            sortedPairs,
+            TComparer<TPair<string, Integer>>
+                .Construct(function(const Left, Right: TPair<string, Integer>): Integer begin Result := Left.Value - Right.Value; end)
+        );
+
+        for pair in sortedPairs do
+            ABuilder.AppendLine(indentStr + Format('  [%d] %s: %s', [pair.Value, pair.Key, FValues[pair.Value].ToString]));
     end
     else
     begin
@@ -85,9 +139,7 @@ begin
     if Assigned(FParent) then
     begin
         ABuilder.AppendLine(indentStr + '[Parent Scope]');
-        // As FParent is now an interface, we must cast it back to the class to call the private DumpScope.
+        // This cast is necessary for this debug helper to access implementation details.
-        // This indicates that DumpScope should perhaps be part of the interface or handled differently.
-        // For now, we use a cast to keep the functionality.
         (FParent as TExecutionScope).DumpScope(ABuilder, AIndent + 2);
     end;
 end;
@@ -107,17 +159,50 @@ begin
 end;
 
 function TExecutionScope.FindValue(const Name: string; out Value: TAstValue): Boolean;
+var
+    index: Integer;
 begin
-    Result := FVariables.TryGetValue(Name, Value);
+    if FNameToIndex.TryGetValue(Name, index) then
-    if not Result and Assigned(FParent) then
     begin
-        Result := FParent.FindValue(Name, Value);
+        Value := FValues[index];
+        Result := True;
+        Exit;
     end;
+
+    if Assigned(FParent) then
+        Result := FParent.FindValue(Name, Value)
+    else
+        Result := False;
+end;
+
+function TExecutionScope.GetValue(Depth, Index: Integer): TAstValue;
+var
+    targetScope: IExecutionScope;
+    i: Integer;
+begin
+    targetScope := Self;
+    for i := 1 to Depth do
+    begin
+        if Assigned(targetScope) then
+            targetScope := targetScope.Parent
+        else
+            // This should not happen if the binder works correctly.
+            raise EInvalidOpException.Create('Invalid scope depth during value retrieval.');
+    end;
+
+    // We must cast back to the implementation to access the private array.
+    Result := (targetScope as TExecutionScope).FValues[Index];
 end;
 
 procedure TExecutionScope.SetValue(const Name: string; const Value: TAstValue);
+var
+    index: Integer;
 begin
-    FVariables.AddOrSetValue(Name, Value);
+    // This method is for pre-binder setup (e.g. native functions) or initial definition.
+    if FNameToIndex.TryGetValue(Name, index) then
+        FValues[index] := Value
+    else
+        Define(Name, Value);
 end;
 
 end.

Src/AST/Myc.Ast.pas

@@ -45,7 +45,7 @@ type
 
         // --- Static method to run the binder ---
         // Traverses the AST and resolves all identifiers. This must be called before evaluating the AST.
-        class procedure Bind(const ARootNode: IExpressionNode); static;
+        class procedure Bind(const ARootNode: IExpressionNode; const AScope: IExecutionScope); static;
     end;
 
     // TAstTraverser provides a default AST traversal implementation.
@@ -73,7 +73,8 @@ implementation
 
 uses
     System.Classes,
-    System.Generics.Collections;
+    System.Generics.Collections,
+    Myc.Ast.Scope; // Needed for the TExecutionScope cast
 
 type
     { TAstNode }
@@ -296,9 +297,11 @@ type
         FParent: TSymbolTable;
         FSymbols: TDictionary<string, TSymbol>;
         FNextSlotIndex: Integer;
+        procedure DefinePreResolved(const Name: string; Index: Integer);
     public
         constructor Create(AParent: TSymbolTable);
         destructor Destroy; override;
+        procedure PopulateFromScope(const AScope: IExecutionScope);
         function Define(const Name: string): TSymbol;
         function Resolve(const Name: string; out Symbol: TSymbol; out Depth: Integer): Boolean;
     end;
@@ -310,12 +313,11 @@ type
         procedure EnterScope;
         procedure ExitScope;
     public
-        constructor Create;
+        constructor Create(AInitialScope: IExecutionScope);
         destructor Destroy; override;
         function VisitIdentifier(const Node: IIdentifierNode): TAstValue; override;
         function VisitLambdaExpression(const Node: ILambdaExpressionNode): TAstValue; override;
         function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue; override;
-        function VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue; override;
     end;
 
 { TConstantNode }
@@ -745,6 +747,38 @@ begin
     inherited;
 end;
 
+procedure TSymbolTable.DefinePreResolved(const Name: string; Index: Integer);
+var
+    symbol: TSymbol;
+begin
+    // Defines a symbol with a specific, pre-determined index.
+    if not FSymbols.ContainsKey(Name) then
+    begin
+        symbol.Name := Name;
+        symbol.SlotIndex := Index;
+        FSymbols.Add(Name, symbol);
+
+        // Ensure the next automatically assigned index is correct.
+        if (Index >= FNextSlotIndex) then
+            FNextSlotIndex := Index + 1;
+    end;
+end;
+
+procedure TSymbolTable.PopulateFromScope(const AScope: IExecutionScope);
+var
+    scopeImpl: TExecutionScope;
+    pair: TPair<string, Integer>;
+begin
+    // ** THE FIX IS HERE **
+    // Iterate over the Key-Value pairs of the scope's dictionary to preserve the exact indices.
+    if not Assigned(AScope) then
+        Exit;
+
+    scopeImpl := (AScope as TExecutionScope);
+    for pair in scopeImpl.NameToIndex do
+        DefinePreResolved(pair.Key, pair.Value);
+end;
+
 function TSymbolTable.Define(const Name: string): TSymbol;
 begin
     Result.Name := Name;
@@ -772,16 +806,41 @@ end;
 
 { TBinder }
 
-constructor TBinder.Create;
+// Helper function to recursively build the symbol table hierarchy
+function CreateSymbolTableFromScope(AScope: IExecutionScope): TSymbolTable;
 begin
-    inherited;
+    if not Assigned(AScope) then
-    FCurrentScope := TSymbolTable.Create(nil); // Start with a global scope
+        Exit(nil);
+
+    // Recursively create the parent symbol table first
+    Result := TSymbolTable.Create(CreateSymbolTableFromScope(AScope.Parent));
+    // Then populate the current level
+    Result.PopulateFromScope(AScope);
+end;
+
+constructor TBinder.Create(AInitialScope: IExecutionScope);
+begin
+    inherited Create;
+    // Correctly and recursively build the symbol table hierarchy from the execution scope.
+    FCurrentScope := CreateSymbolTableFromScope(AInitialScope);
+
+    // If no initial scope was provided, create a single empty root scope.
+    if not Assigned(FCurrentScope) then
+        FCurrentScope := TSymbolTable.Create(nil);
 end;
 
 destructor TBinder.Destroy;
+var
+    scopeToFree: TSymbolTable;
 begin
-    Assert(not Assigned(FCurrentScope.FParent), 'Scope leak in binder.');
+    // The previous Assert was incorrect for binders initialized with nested scopes.
-    FCurrentScope.Free;
+    // This new implementation robustly cleans up the entire symbol table chain.
+    while Assigned(FCurrentScope) do
+    begin
+        scopeToFree := FCurrentScope;
+        FCurrentScope := FCurrentScope.FParent;
+        scopeToFree.Free;
+    end;
     inherited;
 end;
 
@@ -799,17 +858,6 @@ begin
     oldScope.Free;
 end;
 
-function TBinder.VisitBlockExpression(const Node: IBlockExpressionNode): TAstValue;
-begin
-    EnterScope;
-    try
-        // Default traversal of all expressions in the block
-        inherited VisitBlockExpression(Node);
-    finally
-        ExitScope;
-    end;
-end;
-
 function TBinder.VisitIdentifier(const Node: IIdentifierNode): TAstValue;
 var
     symbol: TSymbol;
@@ -836,6 +884,9 @@ var
 begin
     EnterScope;
     try
+        // Reserve a slot for 'Self' first.
+        FCurrentScope.Define('Self');
+
         // 1. Define all parameters in the new scope.
         for param in Node.Parameters do
             FCurrentScope.Define(param.Name);
@@ -850,24 +901,21 @@ end;
 
 function TBinder.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TAstValue;
 begin
-    // 1. First, visit the initializer expression to resolve its identifiers.
+    // For recursive functions, we must define the name in the scope FIRST,
-    if Assigned(Node.Initializer) then
+    // so it can be resolved inside its own initializer (i.e., the lambda body).
-        Node.Initializer.Accept(Self);
-
-    // 2. Then, define the new variable in the current scope.
     FCurrentScope.Define(Node.Identifier.Name);
-
+    inherited;
-    // 3. Finally, visit the declaration's own identifier to resolve it.
-    Node.Identifier.Accept(Self);
 end;
 
 { TAst }
 
-class procedure TAst.Bind(const ARootNode: IExpressionNode);
+class procedure TAst.Bind(const ARootNode: IExpressionNode; const AScope: IExecutionScope);
 var
     binder: IAstVisitor;
 begin
-    binder := TBinder.Create;
+    // Create a binder instance, pre-populating its symbol table with the given scope.
+    binder := TBinder.Create(AScope);
+    // Traverse the AST to resolve all identifiers.
     ARootNode.Accept(binder);
 end;