diff --git a/ASTPlayground/ASTPlayground.dproj b/ASTPlayground/ASTPlayground.dproj
index 4b373f7..b988ee1 100644
--- a/ASTPlayground/ASTPlayground.dproj
+++ b/ASTPlayground/ASTPlayground.dproj
@@ -4,7 +4,7 @@
         <ProjectVersion>20.3</ProjectVersion>
         <FrameworkType>FMX</FrameworkType>
         <Base>True</Base>
-        <Config Condition="'$(Config)'==''">Debug</Config>
+        <Config Condition="'$(Config)'==''">Release</Config>
         <Platform Condition="'$(Platform)'==''">Win64</Platform>
         <ProjectName Condition="'$(ProjectName)'==''">ASTPlayground</ProjectName>
         <TargetedPlatforms>2</TargetedPlatforms>
diff --git a/Src/AST/Myc.Ast.Debugger.pas b/Src/AST/Myc.Ast.Debugger.pas
index 8254ddb..d31e7a3 100644
--- a/Src/AST/Myc.Ast.Debugger.pas
+++ b/Src/AST/Myc.Ast.Debugger.pas
@@ -22,6 +22,7 @@ type
         procedure Unindent;
         procedure AppendLine(const S: string);
         procedure ShowScope;
+
     protected
         // Overridden to provide the debug-specific visitor factory.
         function CreateVisitorFactory: TVisitorFactory; override;
diff --git a/Src/AST/Myc.Ast.Evaluator.pas b/Src/AST/Myc.Ast.Evaluator.pas
index 27256e8..5416721 100644
--- a/Src/AST/Myc.Ast.Evaluator.pas
+++ b/Src/AST/Myc.Ast.Evaluator.pas
@@ -21,18 +21,11 @@ type
     private
         FScope: IExecutionScope;
     protected
-        function IsTruthy(const AValue: TDataValue): Boolean;
+        function IsTruthy(const AValue: TDataValue): Boolean; inline;
 
         // Returns a closure that can create the correct type of visitor for a lambda's body.
         function CreateVisitorFactory: TVisitorFactory; virtual;
 
-        // Creates the callable closure for a lambda expression. No longer virtual.
-        function CreateLambdaClosure(
-            const Node: ILambdaExpressionNode;
-            const ACapturedCells: TArray<IValueCell>;
-            const AClosureScope: IExecutionScope
-        ): TDataValue;
-
         property Scope: IExecutionScope read FScope;
     public
         constructor Create(const AScope: IExecutionScope);
@@ -128,57 +121,6 @@ begin
     end;
 end;
 
-function TEvaluatorVisitor.CreateLambdaClosure(
-    const Node: ILambdaExpressionNode;
-    const ACapturedCells: TArray<IValueCell>;
-    const AClosureScope: IExecutionScope
-): TDataValue;
-var
-    closureValue: TDataValue;
-    visitorFactory: TVisitorFactory;
-begin
-    // Get the appropriate factory via virtual dispatch.
-    visitorFactory := CreateVisitorFactory();
-
-    closureValue :=
-        TDataValue.TFunc(
-            function(const ArgValues: TArray<TDataValue>): TDataValue
-            var
-                lambdaScope: IExecutionScope;
-                bodyVisitor: IAstVisitor;
-                i: Integer;
-                adr: TResolvedAddress;
-            begin
-                if (Length(ArgValues) <> Length(Node.Parameters)) then
-                    raise EArgumentException
-                        .CreateFmt('Argument count mismatch: expected %d, got %d', [Length(Node.Parameters), Length(ArgValues)]);
-
-                lambdaScope := TExecutionScope.Create(AClosureScope, Node.ScopeDescriptor, ACapturedCells);
-
-                adr.Kind := akLocalOrParent;
-                adr.ScopeDepth := 0;
-
-                // Set 'Self' (slot 0) to the captured closureValue for recursion.
-                adr.SlotIndex := 0;
-                lambdaScope.Cell[adr].Value := closureValue;
-
-                // Populate the actual parameters.
-                for i := 0 to High(ArgValues) do
-                begin
-                    adr.SlotIndex := Node.Parameters[i].Address.SlotIndex;
-                    lambdaScope.Cell[adr].Value := ArgValues[i];
-                end;
-
-                // Use the injected factory to create the visitor for the lambda's body.
-                bodyVisitor := visitorFactory(lambdaScope);
-
-                Result := Node.Body.Accept(bodyVisitor);
-            end
-        );
-
-    Result := closureValue;
-end;
-
 function TEvaluatorVisitor.VisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
 var
     capturedCells: TArray<IValueCell>;
diff --git a/Src/AST/Myc.Ast.Scope.pas b/Src/AST/Myc.Ast.Scope.pas
index 068bb67..d143dc8 100644
--- a/Src/AST/Myc.Ast.Scope.pas
+++ b/Src/AST/Myc.Ast.Scope.pas
@@ -13,13 +13,16 @@ type
     TExecutionScope = class(TInterfacedObject, IExecutionScope)
     private
         FParent: IExecutionScope;
+        FDescriptor: IScopeDescriptor;
         FValues: TArray<IValueCell>;
         // Stores references to the value cells captured by a closure.
         FCapturedUpvalues: TArray<IValueCell>;
         FNameToIndex: TDictionary<string, Integer>;
         procedure DumpScope(const ABuilder: TStringBuilder; AIndent: Integer);
+        procedure NeedNameToIndex;
         function GetParent: IExecutionScope;
         function GetCell(const Address: TResolvedAddress): IValueCell;
+        function GetNameToIndex: TDictionary<string, Integer>;
     public
         constructor Create(
             AParent: IExecutionScope = nil;
@@ -30,7 +33,7 @@ type
         procedure Clear;
         function Dump: string;
         procedure Define(const Name: string; const Value: TDataValue);
-        property NameToIndex: TDictionary<string, Integer> read FNameToIndex;
+        property NameToIndex: TDictionary<string, Integer> read GetNameToIndex;
         property Parent: IExecutionScope read FParent;
         property Values: TArray<IValueCell> read FValues;
     end;
@@ -73,15 +76,12 @@ var
 begin
     inherited Create;
     FParent := AParent;
+    FDescriptor := ADescriptor;
     FValues := [];
-    FNameToIndex := TDictionary<string, Integer>.Create;
     FCapturedUpvalues := ACapturedUpvalues; // Store upvalues
 
     if ADescriptor <> nil then
     begin
-        for var item in ADescriptor.Symbols do
-            FNameToIndex.AddOrSetValue(item.Key, item.Value);
-
         slotCount := ADescriptor.SlotCount;
         SetLength(FValues, slotCount);
         for i := 0 to slotCount - 1 do
@@ -91,7 +91,7 @@ end;
 
 destructor TExecutionScope.Destroy;
 begin
-    FNameToIndex.Free;
+    Clear;
     inherited Destroy;
 end;
 
@@ -134,13 +134,15 @@ end;
 procedure TExecutionScope.Clear;
 begin
     FValues := [];
-    FNameToIndex.Clear;
+    FreeAndNil(FNameToIndex);
 end;
 
-procedure TExecutionScope.Define(const Name: string; const Value: TDataValue); // <-- Changed from TAstValue
+procedure TExecutionScope.Define(const Name: string; const Value: TDataValue);
 var
     index: Integer;
 begin
+    NeedNameToIndex;
+
     if FNameToIndex.ContainsKey(Name) then
         raise Exception.CreateFmt('Variable "%s" is already defined in this scope.', [Name]);
 
@@ -157,8 +159,10 @@ var
     indentStr: string;
     sortedPairs: TArray<TPair<string, Integer>>;
 begin
+    NeedNameToIndex;
+
     indentStr := ''.PadLeft(AIndent);
-    if (FNameToIndex.Count > 0) then
+    if FNameToIndex.Count > 0 then
     begin
         sortedPairs := FNameToIndex.ToArray;
         TArray.Sort<TPair<string, Integer>>(
@@ -197,4 +201,23 @@ begin
     end;
 end;
 
+function TExecutionScope.GetNameToIndex: TDictionary<string, Integer>;
+begin
+    NeedNameToIndex;
+    Result := FNameToIndex;
+end;
+
+procedure TExecutionScope.NeedNameToIndex;
+begin
+    if FNameToIndex = nil then
+    begin
+        FNameToIndex := TDictionary<string, Integer>.Create;
+        if FDescriptor <> nil then
+        begin
+            for var item in FDescriptor.Symbols do
+                FNameToIndex.AddOrSetValue(item.Key, item.Value);
+        end;
+    end;
+end;
+
 end.