Binder refactoring, Monster refactoring

Src/AST/Myc.Ast.JSON.pas

@@ -20,9 +20,9 @@ type
 
     // TJsonAstConverter implements the visitor pattern for serialization
     // and uses factory functions for deserialization.
-    TJsonAstConverter = class(TAstVisitor, IJsonAstConverter)
+    // Inherits from the new generic visitor base class
+    TJsonAstConverter = class(TAstVisitor<TJSONObject>, IJsonAstConverter)
     private
-        FJsonObjectStack: TStack<TJSONObject>;
         procedure DataValueToJson(const AValue: TDataValue; const AParent: TJSONObject; const AName: string);
         function JsonToNode(const AJson: TJSONValue; const ExpectedType: String = ''): IAstNode;
         function JsonToDataValue(const AObj: TJSONObject; const AName: string): TDataValue;
@@ -52,37 +52,36 @@ type
         function JsonToAddSeriesItemNode(const AObj: TJSONObject): IAddSeriesItemNode;
         function JsonToSeriesLengthNode(const AObj: TJSONObject): ISeriesLengthNode;
     protected
-        // IAstVisitor implementation for serialization
-        function VisitConstant(const Node: IConstantNode): TDataValue; override;
-        function VisitIdentifier(const Node: IIdentifierNode): TDataValue; override;
-        function VisitKeyword(const Node: IKeywordNode): TDataValue; override;
-        function VisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue; override;
-        function VisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue; override;
-        function VisitIfExpression(const Node: IIfExpressionNode): TDataValue; override;
-        function VisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue; override;
-        function VisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue; override;
-        function VisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue; override;
-        function VisitQuasiquote(const Node: IQuasiquoteNode): TDataValue; override;
-        function VisitUnquote(const Node: IUnquoteNode): TDataValue; override;
-        function VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue; override;
-        function VisitFunctionCall(const Node: IFunctionCallNode): TDataValue; override;
-        function VisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue; override;
-        function VisitRecurNode(const Node: IRecurNode): TDataValue; override;
-        function VisitBlockExpression(const Node: IBlockExpressionNode): TDataValue; override;
-        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue; override;
-        function VisitAssignment(const Node: IAssignmentNode): TDataValue; override;
-        function VisitIndexer(const Node: IIndexerNode): TDataValue; override;
-        function VisitMemberAccess(const Node: IMemberAccessNode): TDataValue; override;
-        function VisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue; override;
-        function VisitCreateSeries(const Node: ICreateSeriesNode): TDataValue; override;
-        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue; override;
-        function VisitSeriesLength(const Node: ISeriesLengthNode): TDataValue; override;
+        // IAstVisitor implementation for serialization (T = TJSONObject)
+        function VisitConstant(const Node: IConstantNode): TJSONObject; override;
+        function VisitIdentifier(const Node: IIdentifierNode): TJSONObject; override;
+        function VisitKeyword(const Node: IKeywordNode): TJSONObject; override;
+        function VisitBinaryExpression(const Node: IBinaryExpressionNode): TJSONObject; override;
+        function VisitUnaryExpression(const Node: IUnaryExpressionNode): TJSONObject; override;
+        function VisitIfExpression(const Node: IIfExpressionNode): TJSONObject; override;
+        function VisitTernaryExpression(const Node: ITernaryExpressionNode): TJSONObject; override;
+        function VisitLambdaExpression(const Node: ILambdaExpressionNode): TJSONObject; override;
+        function VisitMacroDefinition(const Node: IMacroDefinitionNode): TJSONObject; override;
+        function VisitQuasiquote(const Node: IQuasiquoteNode): TJSONObject; override;
+        function VisitUnquote(const Node: IUnquoteNode): TJSONObject; override;
+        function VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TJSONObject; override;
+        function VisitFunctionCall(const Node: IFunctionCallNode): TJSONObject; override;
+        function VisitMacroExpansionNode(const Node: IMacroExpansionNode): TJSONObject; override;
+        function VisitRecurNode(const Node: IRecurNode): TJSONObject; override;
+        function VisitBlockExpression(const Node: IBlockExpressionNode): TJSONObject; override;
+        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): TJSONObject; override;
+        function VisitAssignment(const Node: IAssignmentNode): TJSONObject; override;
+        function VisitIndexer(const Node: IIndexerNode): TJSONObject; override;
+        function VisitMemberAccess(const Node: IMemberAccessNode): TJSONObject; override;
+        function VisitRecordLiteral(const Node: IRecordLiteralNode): TJSONObject; override;
+        function VisitCreateSeries(const Node: ICreateSeriesNode): TJSONObject; override;
+        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): TJSONObject; override;
+        function VisitSeriesLength(const Node: ISeriesLengthNode): TJSONObject; override;
 
         function Serialize(const RootNode: IAstNode): TJSONObject;
         function Deserialize(const AJson: TJSONObject): IAstNode;
     public
         constructor Create;
-        destructor Destroy; override;
     end;
 
 implementation
@@ -95,13 +94,7 @@ uses
 constructor TJsonAstConverter.Create;
 begin
     inherited;
-    FJsonObjectStack := TStack<TJSONObject>.Create;
-end;
-
-destructor TJsonAstConverter.Destroy;
-begin
-    FJsonObjectStack.Free;
-    inherited;
+    // FJsonObjectStack removed
 end;
 
 function TJsonAstConverter.Deserialize(const AJson: TJSONObject): IAstNode;
@@ -145,506 +138,322 @@ begin
     AParent.AddPair(AName, valObj);
 end;
 
-function TJsonAstConverter.VisitConstant(const Node: IConstantNode): TDataValue;
-var
-    obj: TJSONObject;
+function TJsonAstConverter.VisitConstant(const Node: IConstantNode): TJSONObject;
 begin
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Constant'));
-    DataValueToJson(Node.Value, obj, 'Value');
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Constant'));
+    DataValueToJson(Node.Value, Result, 'Value');
 end;
 
-function TJsonAstConverter.VisitIdentifier(const Node: IIdentifierNode): TDataValue;
-var
-    obj: TJSONObject;
+function TJsonAstConverter.VisitIdentifier(const Node: IIdentifierNode): TJSONObject;
 begin
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Identifier'));
-    obj.AddPair('Name', TJSONString.Create(Node.Name));
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Identifier'));
+    Result.AddPair('Name', TJSONString.Create(Node.Name));
 end;
 
-function TJsonAstConverter.VisitKeyword(const Node: IKeywordNode): TDataValue;
-var
-    obj: TJSONObject;
+function TJsonAstConverter.VisitKeyword(const Node: IKeywordNode): TJSONObject;
 begin
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Keyword'));
-    obj.AddPair('Name', TJSONString.Create(Node.Value.Name));
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Keyword'));
+    Result.AddPair('Name', TJSONString.Create(Node.Value.Name));
 end;
 
-function TJsonAstConverter.VisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue;
+function TJsonAstConverter.VisitBinaryExpression(const Node: IBinaryExpressionNode): TJSONObject;
 var
-    obj, leftObj, rightObj: TJSONObject;
+    leftObj, rightObj: TJSONObject;
 begin
-    Node.Left.Accept(Self);
-    Node.Right.Accept(Self);
+    leftObj := Accept(Node.Left);
+    rightObj := Accept(Node.Right);
 
-    rightObj := FJsonObjectStack.Pop;
-    leftObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('BinaryExpr'));
-    obj.AddPair('Operator', TJSONString.Create(Node.Operator.ToString));
-    obj.AddPair('Left', leftObj);
-    obj.AddPair('Right', rightObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('BinaryExpr'));
+    Result.AddPair('Operator', TJSONString.Create(Node.Operator.ToString));
+    Result.AddPair('Left', leftObj);
+    Result.AddPair('Right', rightObj);
 end;
 
-function TJsonAstConverter.VisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue;
+function TJsonAstConverter.VisitUnaryExpression(const Node: IUnaryExpressionNode): TJSONObject;
 var
-    obj, rightObj: TJSONObject;
+    rightObj: TJSONObject;
 begin
-    Node.Right.Accept(Self);
-    rightObj := FJsonObjectStack.Pop;
+    rightObj := Accept(Node.Right);
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('UnaryExpr'));
-    obj.AddPair('Operator', TJSONString.Create(Node.Operator.ToString));
-    obj.AddPair('Right', rightObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('UnaryExpr'));
+    Result.AddPair('Operator', TJSONString.Create(Node.Operator.ToString));
+    Result.AddPair('Right', rightObj);
 end;
 
-function TJsonAstConverter.VisitIfExpression(const Node: IIfExpressionNode): TDataValue;
+function TJsonAstConverter.VisitIfExpression(const Node: IIfExpressionNode): TJSONObject;
 var
-    obj, condObj, thenObj, elseObj: TJSONObject;
+    condObj, thenObj, elseObj: TJSONObject;
 begin
-    Node.Condition.Accept(Self);
-    Node.ThenBranch.Accept(Self);
-    if Assigned(Node.ElseBranch) then
-        Node.ElseBranch.Accept(Self);
+    condObj := Accept(Node.Condition);
+    thenObj := Accept(Node.ThenBranch);
+    elseObj := Accept(Node.ElseBranch); // Accept handles nil
 
-    if Assigned(Node.ElseBranch) then
-        elseObj := FJsonObjectStack.Pop
-    else
-        elseObj := nil;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('IfExpr'));
+    Result.AddPair('Condition', condObj);
+    Result.AddPair('ThenBranch', thenObj);
 
-    thenObj := FJsonObjectStack.Pop;
-    condObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('IfExpr'));
-    obj.AddPair('Condition', condObj);
-    obj.AddPair('ThenBranch', thenObj);
     if Assigned(elseObj) then
-        obj.AddPair('ElseBranch', elseObj)
+        Result.AddPair('ElseBranch', elseObj)
     else
-        obj.AddPair('ElseBranch', TJSONNull.Create);
-
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+        Result.AddPair('ElseBranch', TJSONNull.Create);
 end;
 
-function TJsonAstConverter.VisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue;
+function TJsonAstConverter.VisitTernaryExpression(const Node: ITernaryExpressionNode): TJSONObject;
 var
-    obj, condObj, thenObj, elseObj: TJSONObject;
+    condObj, thenObj, elseObj: TJSONObject;
 begin
-    Node.Condition.Accept(Self);
-    Node.ThenBranch.Accept(Self);
-    Node.ElseBranch.Accept(Self);
+    condObj := Accept(Node.Condition);
+    thenObj := Accept(Node.ThenBranch);
+    elseObj := Accept(Node.ElseBranch);
 
-    elseObj := FJsonObjectStack.Pop;
-    thenObj := FJsonObjectStack.Pop;
-    condObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('TernaryExpr'));
-    obj.AddPair('Condition', condObj);
-    obj.AddPair('ThenBranch', thenObj);
-    obj.AddPair('ElseBranch', elseObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('TernaryExpr'));
+    Result.AddPair('Condition', condObj);
+    Result.AddPair('ThenBranch', thenObj);
+    Result.AddPair('ElseBranch', elseObj);
 end;
 
-function TJsonAstConverter.VisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
+function TJsonAstConverter.VisitLambdaExpression(const Node: ILambdaExpressionNode): TJSONObject;
 var
-    obj, bodyObj: TJSONObject;
+    bodyObj: TJSONObject;
     paramsArray: TJSONArray;
-    tempParams: TArray<TJSONObject>;
-    param: IIdentifierNode;
-    i: Integer;
 begin
-    for param in Node.Parameters do
-        param.Accept(Self);
-    Node.Body.Accept(Self);
-
-    bodyObj := FJsonObjectStack.Pop;
-
-    SetLength(tempParams, Length(Node.Parameters));
-    for i := High(tempParams) downto 0 do
-        tempParams[i] := FJsonObjectStack.Pop;
+    bodyObj := Accept(Node.Body);
 
     paramsArray := TJSONArray.Create;
-    for i := 0 to High(tempParams) do
-        paramsArray.Add(tempParams[i]);
+    for var param in Node.Parameters do
+        paramsArray.Add(Accept(param));
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('LambdaExpr'));
-    obj.AddPair('Parameters', paramsArray);
-    obj.AddPair('Body', bodyObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('LambdaExpr'));
+    Result.AddPair('Parameters', paramsArray);
+    Result.AddPair('Body', bodyObj);
 end;
 
-function TJsonAstConverter.VisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue;
+function TJsonAstConverter.VisitMacroDefinition(const Node: IMacroDefinitionNode): TJSONObject;
 var
-    obj, nameObj, bodyObj: TJSONObject;
+    nameObj, bodyObj: TJSONObject;
     paramsArray: TJSONArray;
-    tempParams: TArray<TJSONObject>;
-    param: IIdentifierNode;
-    i: Integer;
 begin
-    Node.Name.Accept(Self);
-    for param in Node.Parameters do
-        param.Accept(Self);
-    Node.Body.Accept(Self);
-
-    bodyObj := FJsonObjectStack.Pop;
-
-    SetLength(tempParams, Length(Node.Parameters));
-    for i := High(tempParams) downto 0 do
-        tempParams[i] := FJsonObjectStack.Pop;
-
-    nameObj := FJsonObjectStack.Pop;
+    nameObj := Accept(Node.Name);
+    bodyObj := Accept(Node.Body);
 
     paramsArray := TJSONArray.Create;
-    for i := 0 to High(tempParams) do
-        paramsArray.Add(tempParams[i]);
+    for var param in Node.Parameters do
+        paramsArray.Add(Accept(param));
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('MacroDef'));
-    obj.AddPair('Name', nameObj);
-    obj.AddPair('Parameters', paramsArray);
-    obj.AddPair('Body', bodyObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('MacroDef'));
+    Result.AddPair('Name', nameObj);
+    Result.AddPair('Parameters', paramsArray);
+    Result.AddPair('Body', bodyObj);
 end;
 
-function TJsonAstConverter.VisitQuasiquote(const Node: IQuasiquoteNode): TDataValue;
-var
-    obj, exprObj: TJSONObject;
+function TJsonAstConverter.VisitQuasiquote(const Node: IQuasiquoteNode): TJSONObject;
 begin
-    Node.Expression.Accept(Self);
-    exprObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Quasiquote'));
-    obj.AddPair('Expression', exprObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Quasiquote'));
+    Result.AddPair('Expression', Accept(Node.Expression));
 end;
 
-function TJsonAstConverter.VisitUnquote(const Node: IUnquoteNode): TDataValue;
-var
-    obj, exprObj: TJSONObject;
+function TJsonAstConverter.VisitUnquote(const Node: IUnquoteNode): TJSONObject;
 begin
-    Node.Expression.Accept(Self);
-    exprObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Unquote'));
-    obj.AddPair('Expression', exprObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Unquote'));
+    Result.AddPair('Expression', Accept(Node.Expression));
 end;
 
-function TJsonAstConverter.VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue;
-var
-    obj, exprObj: TJSONObject;
+function TJsonAstConverter.VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TJSONObject;
 begin
-    Node.Expression.Accept(Self);
-    exprObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('UnquoteSplicing'));
-    obj.AddPair('Expression', exprObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('UnquoteSplicing'));
+    Result.AddPair('Expression', Accept(Node.Expression));
 end;
 
-function TJsonAstConverter.VisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
+function TJsonAstConverter.VisitFunctionCall(const Node: IFunctionCallNode): TJSONObject;
 var
-    obj, calleeObj: TJSONObject;
+    calleeObj: TJSONObject;
     argsArray: TJSONArray;
-    tempArgs: TArray<TJSONObject>;
     arg: IAstNode;
-    i: Integer;
 begin
-    Node.Callee.Accept(Self);
-    for arg in Node.Arguments do
-        arg.Accept(Self);
-
-    SetLength(tempArgs, Length(Node.Arguments));
-    for i := High(tempArgs) downto 0 do
-        tempArgs[i] := FJsonObjectStack.Pop;
+    calleeObj := Accept(Node.Callee);
 
     argsArray := TJSONArray.Create;
-    for i := 0 to High(tempArgs) do
-        argsArray.Add(tempArgs[i]);
+    for arg in Node.Arguments do
+        argsArray.Add(Accept(arg));
 
-    calleeObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('FunctionCall'));
-    obj.AddPair('Callee', calleeObj);
-    obj.AddPair('Arguments', argsArray);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('FunctionCall'));
+    Result.AddPair('Callee', calleeObj);
+    Result.AddPair('Arguments', argsArray);
 end;
 
-function TJsonAstConverter.VisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue;
+function TJsonAstConverter.VisitMacroExpansionNode(const Node: IMacroExpansionNode): TJSONObject;
 var
-    obj, calleeObj, bodyObj: TJSONObject;
+    calleeObj, bodyObj: TJSONObject;
     argsArray: TJSONArray;
-    tempArgs: TArray<TJSONObject>;
     arg: IAstNode;
-    i: Integer;
 begin
-    // Serialize all children first: Callee, Arguments, and the new ExpandedBody
-    Node.Callee.Accept(Self);
-    for arg in Node.Arguments do
-        arg.Accept(Self);
-    Node.ExpandedBody.Accept(Self);
-
-    // Pop children's JSON from stack in reverse order of visitation
-    bodyObj := FJsonObjectStack.Pop;
-
-    SetLength(tempArgs, Length(Node.Arguments));
-    for i := High(tempArgs) downto 0 do
-        tempArgs[i] := FJsonObjectStack.Pop;
-
-    calleeObj := FJsonObjectStack.Pop;
-
-    // Build JSON array for arguments
-    argsArray := TJSONArray.Create;
-    for var argObj in tempArgs do
-        argsArray.Add(argObj);
-
-    // Create the final JSON object for this node
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('MacroExpansion'));
-    obj.AddPair('Callee', calleeObj);
-    obj.AddPair('Arguments', argsArray);
-    obj.AddPair('ExpandedBody', bodyObj);
-
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
-end;
-
-function TJsonAstConverter.VisitRecurNode(const Node: IRecurNode): TDataValue;
-var
-    obj: TJSONObject;
-    argsArray: TJSONArray;
-    tempArgs: TArray<TJSONObject>;
-    arg: IAstNode;
-    i: Integer;
-begin
-    for arg in Node.Arguments do
-        arg.Accept(Self);
-
-    SetLength(tempArgs, Length(Node.Arguments));
-    for i := High(tempArgs) downto 0 do
-        tempArgs[i] := FJsonObjectStack.Pop;
+    calleeObj := Accept(Node.Callee);
+    bodyObj := Accept(Node.ExpandedBody);
 
     argsArray := TJSONArray.Create;
-    for i := 0 to High(tempArgs) do
-        argsArray.Add(tempArgs[i]);
+    for arg in Node.Arguments do
+        argsArray.Add(Accept(arg));
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Recur'));
-    obj.AddPair('Arguments', argsArray);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('MacroExpansion'));
+    Result.AddPair('Callee', calleeObj);
+    Result.AddPair('Arguments', argsArray);
+    Result.AddPair('ExpandedBody', bodyObj);
 end;
 
-function TJsonAstConverter.VisitBlockExpression(const Node: IBlockExpressionNode): TDataValue;
+function TJsonAstConverter.VisitRecurNode(const Node: IRecurNode): TJSONObject;
+var
+    argsArray: TJSONArray;
+    arg: IAstNode;
+begin
+    argsArray := TJSONArray.Create;
+    for arg in Node.Arguments do
+        argsArray.Add(Accept(arg));
+
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Recur'));
+    Result.AddPair('Arguments', argsArray);
+end;
+
+function TJsonAstConverter.VisitBlockExpression(const Node: IBlockExpressionNode): TJSONObject;
 var
-    obj: TJSONObject;
     exprsArray: TJSONArray;
-    tempExprs: TArray<TJSONObject>;
     expr: IAstNode;
-    i: Integer;
 begin
-    for expr in Node.Expressions do
-        expr.Accept(Self);
-
-    SetLength(tempExprs, Length(Node.Expressions));
-    for i := High(tempExprs) downto 0 do
-        tempExprs[i] := FJsonObjectStack.Pop;
-
     exprsArray := TJSONArray.Create;
-    for i := 0 to High(tempExprs) do
-        exprsArray.Add(tempExprs[i]);
+    for expr in Node.Expressions do
+        exprsArray.Add(Accept(expr));
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Block'));
-    obj.AddPair('Expressions', exprsArray);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Block'));
+    Result.AddPair('Expressions', exprsArray);
 end;
 
-function TJsonAstConverter.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue;
+function TJsonAstConverter.VisitVariableDeclaration(const Node: IVariableDeclarationNode): TJSONObject;
 var
-    obj, identObj, initObj: TJSONObject;
+    identObj, initObj: TJSONObject;
 begin
-    Node.Identifier.Accept(Self);
-    if Assigned(Node.Initializer) then
-        Node.Initializer.Accept(Self);
+    identObj := Accept(Node.Identifier);
+    initObj := Accept(Node.Initializer); // Accept handles nil
 
-    if Assigned(Node.Initializer) then
-        initObj := FJsonObjectStack.Pop
-    else
-        initObj := nil;
-    identObj := FJsonObjectStack.Pop;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('VarDecl'));
+    Result.AddPair('Identifier', identObj);
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('VarDecl'));
-    obj.AddPair('Identifier', identObj);
     if Assigned(initObj) then
-        obj.AddPair('Initializer', initObj)
+        Result.AddPair('Initializer', initObj)
     else
-        obj.AddPair('Initializer', TJSONNull.Create);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+        Result.AddPair('Initializer', TJSONNull.Create);
 end;
 
-function TJsonAstConverter.VisitAssignment(const Node: IAssignmentNode): TDataValue;
+function TJsonAstConverter.VisitAssignment(const Node: IAssignmentNode): TJSONObject;
 var
-    obj, identObj, valueObj: TJSONObject;
+    identObj, valueObj: TJSONObject;
 begin
-    Node.Identifier.Accept(Self);
-    Node.Value.Accept(Self);
+    identObj := Accept(Node.Identifier);
+    valueObj := Accept(Node.Value);
 
-    valueObj := FJsonObjectStack.Pop;
-    identObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Assignment'));
-    obj.AddPair('Identifier', identObj);
-    obj.AddPair('Value', valueObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Assignment'));
+    Result.AddPair('Identifier', identObj);
+    Result.AddPair('Value', valueObj);
 end;
 
-function TJsonAstConverter.VisitIndexer(const Node: IIndexerNode): TDataValue;
+function TJsonAstConverter.VisitIndexer(const Node: IIndexerNode): TJSONObject;
 var
-    obj, baseObj, indexObj: TJSONObject;
+    baseObj, indexObj: TJSONObject;
 begin
-    Node.Base.Accept(Self);
-    Node.Index.Accept(Self);
+    baseObj := Accept(Node.Base);
+    indexObj := Accept(Node.Index);
 
-    indexObj := FJsonObjectStack.Pop;
-    baseObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('Indexer'));
-    obj.AddPair('Base', baseObj);
-    obj.AddPair('Index', indexObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('Indexer'));
+    Result.AddPair('Base', baseObj);
+    Result.AddPair('Index', indexObj);
 end;
 
-function TJsonAstConverter.VisitMemberAccess(const Node: IMemberAccessNode): TDataValue;
+function TJsonAstConverter.VisitMemberAccess(const Node: IMemberAccessNode): TJSONObject;
 var
-    obj, baseObj, memberObj: TJSONObject;
+    baseObj, memberObj: TJSONObject;
 begin
-    Node.Base.Accept(Self);
-    Node.Member.Accept(Self);
+    baseObj := Accept(Node.Base);
+    memberObj := Accept(Node.Member);
 
-    memberObj := FJsonObjectStack.Pop;
-    baseObj := FJsonObjectStack.Pop;
-
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('MemberAccess'));
-    obj.AddPair('Base', baseObj);
-    obj.AddPair('Member', memberObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('MemberAccess'));
+    Result.AddPair('Base', baseObj);
+    Result.AddPair('Member', memberObj);
 end;
 
-function TJsonAstConverter.VisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue;
+function TJsonAstConverter.VisitRecordLiteral(const Node: IRecordLiteralNode): TJSONObject;
 var
-    obj, fieldObj: TJSONObject;
     fieldsArray: TJSONArray;
     field: TRecordFieldLiteral;
+    fieldObj: TJSONObject;
 begin
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('RecordLiteral'));
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('RecordLiteral'));
 
     fieldsArray := TJSONArray.Create;
     for field in Node.Fields do
     begin
-        field.Value.Accept(Self); // This pushes the value JSON onto the stack
-
         fieldObj := TJSONObject.Create;
         fieldObj.AddPair('Name', TJSONString.Create(field.Key.Value.Name));
-        fieldObj.AddPair('Value', FJsonObjectStack.Pop);
+        fieldObj.AddPair('Value', Accept(field.Value)); // Get TJSONObject
         fieldsArray.Add(fieldObj);
     end;
 
-    obj.AddPair('Fields', fieldsArray);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result.AddPair('Fields', fieldsArray);
 end;
 
-function TJsonAstConverter.VisitCreateSeries(const Node: ICreateSeriesNode): TDataValue;
-var
-    obj: TJSONObject;
+function TJsonAstConverter.VisitCreateSeries(const Node: ICreateSeriesNode): TJSONObject;
 begin
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('CreateSeries'));
-    obj.AddPair('Definition', TJSONString.Create(Node.Definition));
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('CreateSeries'));
+    Result.AddPair('Definition', TJSONString.Create(Node.Definition));
 end;
 
-function TJsonAstConverter.VisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue;
+function TJsonAstConverter.VisitAddSeriesItem(const Node: IAddSeriesItemNode): TJSONObject;
 var
-    obj, seriesObj, valueObj, lookbackObj: TJSONObject;
+    seriesObj, valueObj, lookbackObj: TJSONObject;
 begin
-    Node.Series.Accept(Self);
-    Node.Value.Accept(Self);
-    if Assigned(Node.Lookback) then
-        Node.Lookback.Accept(Self);
+    seriesObj := Accept(Node.Series);
+    valueObj := Accept(Node.Value);
+    lookbackObj := Accept(Node.Lookback); // Accept handles nil
 
-    if Assigned(Node.Lookback) then
-        lookbackObj := FJsonObjectStack.Pop
-    else
-        lookbackObj := nil;
-    valueObj := FJsonObjectStack.Pop;
-    seriesObj := FJsonObjectStack.Pop;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('AddSeriesItem'));
+    Result.AddPair('Series', seriesObj);
+    Result.AddPair('Value', valueObj);
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('AddSeriesItem'));
-    obj.AddPair('Series', seriesObj);
-    obj.AddPair('Value', valueObj);
     if Assigned(lookbackObj) then
-        obj.AddPair('Lookback', lookbackObj)
+        Result.AddPair('Lookback', lookbackObj)
     else
-        obj.AddPair('Lookback', TJSONNull.Create);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+        Result.AddPair('Lookback', TJSONNull.Create);
 end;
 
-function TJsonAstConverter.VisitSeriesLength(const Node: ISeriesLengthNode): TDataValue;
+function TJsonAstConverter.VisitSeriesLength(const Node: ISeriesLengthNode): TJSONObject;
 var
-    obj, seriesObj: TJSONObject;
+    seriesObj: TJSONObject;
 begin
-    Node.Series.Accept(Self);
-    seriesObj := FJsonObjectStack.Pop;
+    seriesObj := Accept(Node.Series);
 
-    obj := TJSONObject.Create;
-    obj.AddPair('NodeType', TJSONString.Create('SeriesLength'));
-    obj.AddPair('Series', seriesObj);
-    FJsonObjectStack.Push(obj);
-    Result := TDataValue.Void;
+    Result := TJSONObject.Create;
+    Result.AddPair('NodeType', TJSONString.Create('SeriesLength'));
+    Result.AddPair('Series', seriesObj);
 end;
 
 { TJsonAstConverter - Deserialization }
@@ -827,7 +636,7 @@ end;
 
 function TJsonAstConverter.JsonToUnquoteSplicingNode(const AObj: TJSONObject): IUnquoteSplicingNode;
 begin
-    Result := TAst.UnquoteSplicing(JsonToNode(AObj.GetValue('Expression')));
+    Result := TAst.UnquoteSplicing(JsonToNode(AObj.GetValue('Expression')).AsQuasiquote);
 end;
 
 function TJsonAstConverter.JsonToFunctionCallNode(const AObj: TJSONObject): IFunctionCallNode;
@@ -1020,16 +829,12 @@ end;
 
 function TJsonAstConverter.Serialize(const RootNode: IAstNode): TJSONObject;
 begin
-    FJsonObjectStack.Clear;
     if not Assigned(RootNode) then
         exit(nil);
 
-    RootNode.Accept(Self);
-
-    if FJsonObjectStack.Count <> 1 then
-        raise EInvalidOpException.Create('JSON serialization stack is corrupt.');
-
-    Result := FJsonObjectStack.Pop;
+    // Call Accept, which returns TDataValue(vkGeneric(TJSONObject))
+    // and unwrap it.
+    Result := RootNode.Accept(Self).AsGeneric<TJSONObject>;
 end;
 
 end.