unit Myc.Ast.Visitor;

interface

uses
    System.SysUtils,
    System.Generics.Collections,
    Myc.Data.Value,
    Myc.Ast,
    Myc.Ast.Nodes;

type
    TAstVisitor<T> = class abstract(TInterfacedObject, IAstVisitor)
    strict private
        // IAstVisitor explicit implementation (bridge methods)
        function IAstVisitor.VisitConstant = DoVisitConstant;
        function IAstVisitor.VisitIdentifier = DoVisitIdentifier;
        function IAstVisitor.VisitKeyword = DoVisitKeyword;
        function IAstVisitor.VisitBinaryExpression = DoVisitBinaryExpression;
        function IAstVisitor.VisitUnaryExpression = DoVisitUnaryExpression;
        function IAstVisitor.VisitIfExpression = DoVisitIfExpression;
        function IAstVisitor.VisitTernaryExpression = DoVisitTernaryExpression;
        function IAstVisitor.VisitLambdaExpression = DoVisitLambdaExpression;
        function IAstVisitor.VisitFunctionCall = DoVisitFunctionCall;
        function IAstVisitor.VisitMacroExpansionNode = DoVisitMacroExpansionNode;
        function IAstVisitor.VisitBlockExpression = DoVisitBlockExpression;
        function IAstVisitor.VisitVariableDeclaration = DoVisitVariableDeclaration;
        function IAstVisitor.VisitAssignment = DoVisitAssignment;
        function IAstVisitor.VisitMacroDefinition = DoVisitMacroDefinition;
        function IAstVisitor.VisitQuasiquote = DoVisitQuasiquote;
        function IAstVisitor.VisitUnquote = DoVisitUnquote;
        function IAstVisitor.VisitUnquoteSplicing = DoVisitUnquoteSplicing;
        function IAstVisitor.VisitIndexer = DoVisitIndexer;
        function IAstVisitor.VisitMemberAccess = DoVisitMemberAccess;
        function IAstVisitor.VisitRecordLiteral = DoVisitRecordLiteral;
        function IAstVisitor.VisitCreateSeries = DoVisitCreateSeries;
        function IAstVisitor.VisitAddSeriesItem = DoVisitAddSeriesItem;
        function IAstVisitor.VisitSeriesLength = DoVisitSeriesLength;
        function IAstVisitor.VisitRecurNode = DoVisitRecurNode;
        function IAstVisitor.VisitNop = DoVisitNop; // Added Nop

        // Private bridge method implementations
        function DoVisitConstant(const Node: IConstantNode): TDataValue;
        function DoVisitIdentifier(const Node: IIdentifierNode): TDataValue;
        function DoVisitKeyword(const Node: IKeywordNode): TDataValue;
        function DoVisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue;
        function DoVisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue;
        function DoVisitIfExpression(const Node: IIfExpressionNode): TDataValue;
        function DoVisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue;
        function DoVisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
        function DoVisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
        function DoVisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue;
        function DoVisitBlockExpression(const Node: IBlockExpressionNode): TDataValue;
        function DoVisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue;
        function DoVisitAssignment(const Node: IAssignmentNode): TDataValue;
        function DoVisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue;
        function DoVisitQuasiquote(const Node: IQuasiquoteNode): TDataValue;
        function DoVisitUnquote(const Node: IUnquoteNode): TDataValue;
        function DoVisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue;
        function DoVisitIndexer(const Node: IIndexerNode): TDataValue;
        function DoVisitMemberAccess(const Node: IMemberAccessNode): TDataValue;
        function DoVisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue;
        function DoVisitCreateSeries(const Node: ICreateSeriesNode): TDataValue;
        function DoVisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue;
        function DoVisitSeriesLength(const Node: ISeriesLengthNode): TDataValue;
        function DoVisitRecurNode(const Node: IRecurNode): TDataValue;
        function DoVisitNop(const Node: INopNode): TDataValue; // Added Nop

    protected
        // Visit a node.
        function Accept(const Node: IAstNode): T; virtual;

        function VisitConstant(const Node: IConstantNode): T; virtual; abstract;
        function VisitIdentifier(const Node: IIdentifierNode): T; virtual; abstract;
        function VisitKeyword(const Node: IKeywordNode): T; virtual; abstract;
        function VisitBinaryExpression(const Node: IBinaryExpressionNode): T; virtual; abstract;
        function VisitUnaryExpression(const Node: IUnaryExpressionNode): T; virtual; abstract;
        function VisitIfExpression(const Node: IIfExpressionNode): T; virtual; abstract;
        function VisitTernaryExpression(const Node: ITernaryExpressionNode): T; virtual; abstract;
        function VisitLambdaExpression(const Node: ILambdaExpressionNode): T; virtual; abstract;
        function VisitFunctionCall(const Node: IFunctionCallNode): T; virtual; abstract;
        function VisitMacroExpansionNode(const Node: IMacroExpansionNode): T; virtual; abstract;
        function VisitBlockExpression(const Node: IBlockExpressionNode): T; virtual; abstract;
        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): T; virtual; abstract;
        function VisitAssignment(const Node: IAssignmentNode): T; virtual; abstract;
        function VisitMacroDefinition(const Node: IMacroDefinitionNode): T; virtual; abstract;
        function VisitQuasiquote(const Node: IQuasiquoteNode): T; virtual; abstract;
        function VisitUnquote(const Node: IUnquoteNode): T; virtual; abstract;
        function VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): T; virtual; abstract;
        function VisitIndexer(const Node: IIndexerNode): T; virtual; abstract;
        function VisitMemberAccess(const Node: IMemberAccessNode): T; virtual; abstract;
        function VisitRecordLiteral(const Node: IRecordLiteralNode): T; virtual; abstract;
        function VisitCreateSeries(const Node: ICreateSeriesNode): T; virtual; abstract;
        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): T; virtual; abstract;
        function VisitSeriesLength(const Node: ISeriesLengthNode): T; virtual; abstract;
        function VisitRecurNode(const Node: IRecurNode): T; virtual; abstract;
        function VisitNop(const Node: INopNode): T; virtual; abstract; // Added Nop
    end;

    TAstTransformer = class abstract(TAstVisitor<IAstNode>)
    protected
        function AcceptParameters(const Nodes: TArray<IIdentifierNode>): TArray<IIdentifierNode>;
        function AcceptNodes(const Nodes: TArray<IAstNode>): TArray<IAstNode>;

        function VisitConstant(const Node: IConstantNode): IAstNode; override;
        function VisitIdentifier(const Node: IIdentifierNode): IAstNode; override;
        function VisitKeyword(const Node: IKeywordNode): IAstNode; override;
        function VisitBinaryExpression(const Node: IBinaryExpressionNode): IAstNode; override;
        function VisitUnaryExpression(const Node: IUnaryExpressionNode): IAstNode; override;
        function VisitIfExpression(const Node: IIfExpressionNode): IAstNode; override;
        function VisitTernaryExpression(const Node: ITernaryExpressionNode): IAstNode; override;
        function VisitLambdaExpression(const Node: ILambdaExpressionNode): IAstNode; override;
        function VisitFunctionCall(const Node: IFunctionCallNode): IAstNode; override;
        function VisitMacroExpansionNode(const Node: IMacroExpansionNode): IAstNode; override;
        function VisitBlockExpression(const Node: IBlockExpressionNode): IAstNode; override;
        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): IAstNode; override;
        function VisitAssignment(const Node: IAssignmentNode): IAstNode; override;
        function VisitMacroDefinition(const Node: IMacroDefinitionNode): IAstNode; override;
        function VisitQuasiquote(const Node: IQuasiquoteNode): IAstNode; override;
        function VisitUnquote(const Node: IUnquoteNode): IAstNode; override;
        function VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): IAstNode; override;
        function VisitIndexer(const Node: IIndexerNode): IAstNode; override;
        function VisitMemberAccess(const Node: IMemberAccessNode): IAstNode; override;
        function VisitRecordLiteral(const Node: IRecordLiteralNode): IAstNode; override;
        function VisitCreateSeries(const Node: ICreateSeriesNode): IAstNode; override;
        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode; override;
        function VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode; override;
        function VisitRecurNode(const Node: IRecurNode): IAstNode; override;
        function VisitNop(const Node: INopNode): IAstNode; override; // Added Nop
    end;

    TAstVisitor = class abstract(TInterfacedObject, IAstVisitor)
    strict private
        // IAstVisitor explicit implementation (bridge methods)
        function IAstVisitor.VisitConstant = DoVisitConstant;
        function IAstVisitor.VisitIdentifier = DoVisitIdentifier;
        function IAstVisitor.VisitKeyword = DoVisitKeyword;
        function IAstVisitor.VisitBinaryExpression = DoVisitBinaryExpression;
        function IAstVisitor.VisitUnaryExpression = DoVisitUnaryExpression;
        function IAstVisitor.VisitIfExpression = DoVisitIfExpression;
        function IAstVisitor.VisitTernaryExpression = DoVisitTernaryExpression;
        function IAstVisitor.VisitLambdaExpression = DoVisitLambdaExpression;
        function IAstVisitor.VisitFunctionCall = DoVisitFunctionCall;
        function IAstVisitor.VisitMacroExpansionNode = DoVisitMacroExpansionNode;
        function IAstVisitor.VisitBlockExpression = DoVisitBlockExpression;
        function IAstVisitor.VisitVariableDeclaration = DoVisitVariableDeclaration;
        function IAstVisitor.VisitAssignment = DoVisitAssignment;
        function IAstVisitor.VisitMacroDefinition = DoVisitMacroDefinition;
        function IAstVisitor.VisitQuasiquote = DoVisitQuasiquote;
        function IAstVisitor.VisitUnquote = DoVisitUnquote;
        function IAstVisitor.VisitUnquoteSplicing = DoVisitUnquoteSplicing;
        function IAstVisitor.VisitIndexer = DoVisitIndexer;
        function IAstVisitor.VisitMemberAccess = DoVisitMemberAccess;
        function IAstVisitor.VisitRecordLiteral = DoVisitRecordLiteral;
        function IAstVisitor.VisitCreateSeries = DoVisitCreateSeries;
        function IAstVisitor.VisitAddSeriesItem = DoVisitAddSeriesItem;
        function IAstVisitor.VisitSeriesLength = DoVisitSeriesLength;
        function IAstVisitor.VisitRecurNode = DoVisitRecurNode;
        function IAstVisitor.VisitNop = DoVisitNop; // Added Nop

        // Private bridge method implementations
        function DoVisitConstant(const Node: IConstantNode): TDataValue;
        function DoVisitIdentifier(const Node: IIdentifierNode): TDataValue;
        function DoVisitKeyword(const Node: IKeywordNode): TDataValue;
        function DoVisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue;
        function DoVisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue;
        function DoVisitIfExpression(const Node: IIfExpressionNode): TDataValue;
        function DoVisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue;
        function DoVisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
        function DoVisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
        function DoVisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue;
        function DoVisitBlockExpression(const Node: IBlockExpressionNode): TDataValue;
        function DoVisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue;
        function DoVisitAssignment(const Node: IAssignmentNode): TDataValue;
        function DoVisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue;
        function DoVisitQuasiquote(const Node: IQuasiquoteNode): TDataValue;
        function DoVisitUnquote(const Node: IUnquoteNode): TDataValue;
        function DoVisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue;
        function DoVisitIndexer(const Node: IIndexerNode): TDataValue;
        function DoVisitMemberAccess(const Node: IMemberAccessNode): TDataValue;
        function DoVisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue;
        function DoVisitCreateSeries(const Node: ICreateSeriesNode): TDataValue;
        function DoVisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue;
        function DoVisitSeriesLength(const Node: ISeriesLengthNode): TDataValue;
        function DoVisitRecurNode(const Node: IRecurNode): TDataValue;
        function DoVisitNop(const Node: INopNode): TDataValue; // Added Nop

    protected
        // Virtual procedures for descendants (Interpreters/Side-effects) to override
        procedure VisitConstant(const Node: IConstantNode); virtual; abstract;
        procedure VisitIdentifier(const Node: IIdentifierNode); virtual; abstract;
        procedure VisitKeyword(const Node: IKeywordNode); virtual; abstract;
        procedure VisitBinaryExpression(const Node: IBinaryExpressionNode); virtual; abstract;
        procedure VisitUnaryExpression(const Node: IUnaryExpressionNode); virtual; abstract;
        procedure VisitIfExpression(const Node: IIfExpressionNode); virtual; abstract;
        procedure VisitTernaryExpression(const Node: ITernaryExpressionNode); virtual; abstract;
        procedure VisitLambdaExpression(const Node: ILambdaExpressionNode); virtual; abstract;
        procedure VisitFunctionCall(const Node: IFunctionCallNode); virtual; abstract;
        procedure VisitMacroExpansionNode(const Node: IMacroExpansionNode); virtual; abstract;
        procedure VisitBlockExpression(const Node: IBlockExpressionNode); virtual; abstract;
        procedure VisitVariableDeclaration(const Node: IVariableDeclarationNode); virtual; abstract;
        procedure VisitAssignment(const Node: IAssignmentNode); virtual; abstract;
        procedure VisitMacroDefinition(const Node: IMacroDefinitionNode); virtual; abstract;
        procedure VisitQuasiquote(const Node: IQuasiquoteNode); virtual; abstract;
        procedure VisitUnquote(const Node: IUnquoteNode); virtual; abstract;
        procedure VisitUnquoteSplicing(const Node: IUnquoteSplicingNode); virtual; abstract;
        procedure VisitIndexer(const Node: IIndexerNode); virtual; abstract;
        procedure VisitMemberAccess(const Node: IMemberAccessNode); virtual; abstract;
        procedure VisitRecordLiteral(const Node: IRecordLiteralNode); virtual; abstract;
        procedure VisitCreateSeries(const Node: ICreateSeriesNode); virtual; abstract;
        procedure VisitAddSeriesItem(const Node: IAddSeriesItemNode); virtual; abstract;
        procedure VisitSeriesLength(const Node: ISeriesLengthNode); virtual; abstract;
        procedure VisitRecurNode(const Node: IRecurNode); virtual; abstract;
        procedure VisitNop(const Node: INopNode); virtual; abstract; // Added Nop
    end;

implementation

{ TAstVisitor }

function TAstVisitor<T>.Accept(const Node: IAstNode): T;
begin
    if Assigned(Node) then
        Result := Node.Accept(Self).AsGeneric<T>
    else
        Result := Default(T);
end;

{ TAstVisitor<T> }

function TAstVisitor<T>.DoVisitConstant(const Node: IConstantNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitConstant(Node));
end;

function TAstVisitor<T>.DoVisitIdentifier(const Node: IIdentifierNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitIdentifier(Node));
end;

function TAstVisitor<T>.DoVisitKeyword(const Node: IKeywordNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitKeyword(Node));
end;

function TAstVisitor<T>.DoVisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitBinaryExpression(Node));
end;

function TAstVisitor<T>.DoVisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitUnaryExpression(Node));
end;

function TAstVisitor<T>.DoVisitIfExpression(const Node: IIfExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitIfExpression(Node));
end;

function TAstVisitor<T>.DoVisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitTernaryExpression(Node));
end;

function TAstVisitor<T>.DoVisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitLambdaExpression(Node));
end;

function TAstVisitor<T>.DoVisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitFunctionCall(Node));
end;

function TAstVisitor<T>.DoVisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitMacroExpansionNode(Node));
end;

function TAstVisitor<T>.DoVisitBlockExpression(const Node: IBlockExpressionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitBlockExpression(Node));
end;

function TAstVisitor<T>.DoVisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitVariableDeclaration(Node));
end;

function TAstVisitor<T>.DoVisitAssignment(const Node: IAssignmentNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitAssignment(Node));
end;

function TAstVisitor<T>.DoVisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitMacroDefinition(Node));
end;

function TAstVisitor<T>.DoVisitQuasiquote(const Node: IQuasiquoteNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitQuasiquote(Node));
end;

function TAstVisitor<T>.DoVisitUnquote(const Node: IUnquoteNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitUnquote(Node));
end;

function TAstVisitor<T>.DoVisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitUnquoteSplicing(Node));
end;

function TAstVisitor<T>.DoVisitIndexer(const Node: IIndexerNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitIndexer(Node));
end;

function TAstVisitor<T>.DoVisitMemberAccess(const Node: IMemberAccessNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitMemberAccess(Node));
end;

function TAstVisitor<T>.DoVisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitRecordLiteral(Node));
end;

function TAstVisitor<T>.DoVisitCreateSeries(const Node: ICreateSeriesNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitCreateSeries(Node));
end;

function TAstVisitor<T>.DoVisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitAddSeriesItem(Node));
end;

function TAstVisitor<T>.DoVisitSeriesLength(const Node: ISeriesLengthNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitSeriesLength(Node));
end;

function TAstVisitor<T>.DoVisitRecurNode(const Node: IRecurNode): TDataValue;
begin
    Result := TDataValue.FromGeneric<T>(VisitRecurNode(Node));
end;

function TAstVisitor<T>.DoVisitNop(const Node: INopNode): TDataValue;
begin
    // Added Nop implementation
    Result := TDataValue.FromGeneric<T>(VisitNop(Node));
end;

function TAstTransformer.AcceptParameters(const Nodes: TArray<IIdentifierNode>): TArray<IIdentifierNode>;
var
    i: Integer;
begin
    SetLength(Result, Length(Nodes));
    for i := 0 to High(Nodes) do
        Result[i] := Accept(Nodes[i]).AsIdentifier;
end;

function TAstTransformer.AcceptNodes(const Nodes: TArray<IAstNode>): TArray<IAstNode>;
var
    i: Integer;
    newNode: IAstNode; // Changed from TDataValue
    newList: TList<IAstNode>; // Used if nodes are removed (e.g. defmacro)
begin
    Result := Nodes; // Assume no changes
    newList := nil;

    for i := 0 to High(Nodes) do
    begin
        newNode := Accept(Nodes[i]); // Calls new Accept, returns IAstNode (or nil)

        if not Assigned(newNode) then // Node was removed (e.g. defmacro)
        begin
            if newList = nil then // First change
            begin
                newList := TList<IAstNode>.Create;
                for var j := 0 to i - 1 do
                    newList.Add(Nodes[j]);
            end;
            // else: just skip adding it
        end
        else
        begin
            if newNode <> Nodes[i] then // Node was replaced
            begin
                if newList = nil then // First change
                begin
                    newList := TList<IAstNode>.Create;
                    for var j := 0 to i - 1 do
                        newList.Add(Nodes[j]);
                end;
                newList.Add(newNode);
            end
            else
            begin
                if newList <> nil then // No change, but we are already copying
                    newList.Add(Nodes[i]);
            end;
        end;
    end;

    if newList <> nil then
    begin
        Result := newList.ToArray;
        newList.Free;
    end;
end;

// --- Base Virtual Implementations (IAstNode-based) ---
// --- Implemented with traversal logic from old TAstTransformer ---

function TAstTransformer.VisitConstant(const Node: IConstantNode): IAstNode;
begin
    Result := Node; // Leaf node
end;

function TAstTransformer.VisitIdentifier(const Node: IIdentifierNode): IAstNode;
begin
    Result := Node; // Leaf node
end;

function TAstTransformer.VisitKeyword(const Node: IKeywordNode): IAstNode;
begin
    Result := Node; // Leaf node
end;

function TAstTransformer.VisitNop(const Node: INopNode): IAstNode;
begin
    // Added Nop implementation
    Result := Node; // Leaf node
end;

function TAstTransformer.VisitBinaryExpression(const Node: IBinaryExpressionNode): IAstNode;
var
    N: TBinaryExpressionNode;
begin
    N := (Node as TBinaryExpressionNode);
    N.Left := Accept(N.Left);
    N.Right := Accept(N.Right);
    Result := Node;
end;

function TAstTransformer.VisitUnaryExpression(const Node: IUnaryExpressionNode): IAstNode;
var
    N: TUnaryExpressionNode;
begin
    N := (Node as TUnaryExpressionNode);
    N.Right := Accept(N.Right);
    Result := Node;
end;

function TAstTransformer.VisitIfExpression(const Node: IIfExpressionNode): IAstNode;
var
    N: TIfExpressionNode;
begin
    N := (Node as TIfExpressionNode);
    N.Condition := Accept(N.Condition);
    N.ThenBranch := Accept(N.ThenBranch);
    N.ElseBranch := Accept(N.ElseBranch); // Accept handles nil
    Result := Node;
end;

function TAstTransformer.VisitTernaryExpression(const Node: ITernaryExpressionNode): IAstNode;
var
    N: TTernaryExpressionNode;
begin
    N := (Node as TTernaryExpressionNode);
    N.Condition := Accept(N.Condition);
    N.ThenBranch := Accept(N.ThenBranch);
    N.ElseBranch := Accept(N.ElseBranch);
    Result := Node;
end;

function TAstTransformer.VisitLambdaExpression(const Node: ILambdaExpressionNode): IAstNode;
var
    N: TLambdaExpressionNode;
begin
    N := (Node as TLambdaExpressionNode);
    N.Parameters := AcceptParameters(N.Parameters);
    N.Body := Accept(N.Body);
    Result := Node;
end;

function TAstTransformer.VisitFunctionCall(const Node: IFunctionCallNode): IAstNode;
var
    N: TFunctionCallNode;
begin
    N := (Node as TFunctionCallNode);
    N.Callee := Accept(N.Callee);
    N.Arguments := AcceptNodes(N.Arguments);
    Result := Node;
end;

function TAstTransformer.VisitMacroExpansionNode(const Node: IMacroExpansionNode): IAstNode;
var
    N: TMacroExpansionNode;
begin
    N := (Node as TMacroExpansionNode);

    // ONLY visit the expanded body, as this is the "real" AST node.
    N.ExpandedBody := Accept(N.ExpandedBody);

    // Callee and Arguments are metadata for the visualizer and must NOT be visited
    // by subsequent phases (Binder, TypeChecker, etc.).

    Result := Node; // Return the (mutated) wrapper
end;

function TAstTransformer.VisitBlockExpression(const Node: IBlockExpressionNode): IAstNode;
var
    N: TBlockExpressionNode;
begin
    N := (Node as TBlockExpressionNode);
    N.Expressions := AcceptNodes(N.Expressions);
    Result := Node;
end;

function TAstTransformer.VisitVariableDeclaration(const Node: IVariableDeclarationNode): IAstNode;
var
    N: TVariableDeclarationNode;
begin
    N := (Node as TVariableDeclarationNode);
    N.Identifier := Accept(N.Identifier).AsIdentifier;
    N.Initializer := Accept(N.Initializer); // Accept handles nil
    Result := Node;
end;

function TAstTransformer.VisitAssignment(const Node: IAssignmentNode): IAstNode;
var
    N: TAssignmentNode;
begin
    N := (Node as TAssignmentNode);
    N.Value := Accept(N.Value);
    N.Identifier := Accept(N.Identifier).AsIdentifier;
    Result := Node;
end;

function TAstTransformer.VisitMacroDefinition(const Node: IMacroDefinitionNode): IAstNode;
var
    N: TMacroDefinitionNode;
begin
    N := (Node as TMacroDefinitionNode);
    N.Name := Accept(N.Name).AsIdentifier;
    N.Parameters := AcceptParameters(N.Parameters);
    N.Body := Accept(N.Body);
    Result := Node;
end;

function TAstTransformer.VisitQuasiquote(const Node: IQuasiquoteNode): IAstNode;
var
    N: TQuasiquoteNode;
begin
    N := (Node as TQuasiquoteNode);
    N.Expression := Accept(N.Expression);
    Result := Node;
end;

function TAstTransformer.VisitUnquote(const Node: IUnquoteNode): IAstNode;
var
    N: TUnquoteNode;
begin
    N := (Node as TUnquoteNode);
    N.Expression := Accept(N.Expression);
    Result := Node;
end;

function TAstTransformer.VisitUnquoteSplicing(const Node: IUnquoteSplicingNode): IAstNode;
var
    N: TUnquoteSplicingNode;
begin
    N := (Node as TUnquoteSplicingNode);
    N.Expression := Accept(N.Expression).AsQuasiquote;
    Result := Node;
end;

function TAstTransformer.VisitIndexer(const Node: IIndexerNode): IAstNode;
var
    N: TIndexerNode;
begin
    N := (Node as TIndexerNode);
    N.Base := Accept(N.Base);
    N.Index := Accept(N.Index);
    Result := Node;
end;

function TAstTransformer.VisitMemberAccess(const Node: IMemberAccessNode): IAstNode;
var
    N: TMemberAccessNode;
begin
    N := (Node as TMemberAccessNode);
    N.Base := Accept(N.Base);
    N.Member := Accept(N.Member).AsKeyword;
    Result := Node;
end;

function TAstTransformer.VisitRecordLiteral(const Node: IRecordLiteralNode): IAstNode;
var
    N: TRecordLiteralNode;
    i: Integer;
    newFields: TArray<TRecordFieldLiteral>;
begin
    N := (Node as TRecordLiteralNode);
    // TRecordFieldLiteral ist ein Record, kein IAstNode, wir müssen manuell traversieren
    SetLength(newFields, Length(N.Fields));
    for i := 0 to High(N.Fields) do
    begin
        newFields[i].Key := Accept(N.Fields[i].Key).AsKeyword;
        newFields[i].Value := Accept(N.Fields[i].Value);
    end;
    N.Fields := newFields;
    Result := Node;
end;

function TAstTransformer.VisitCreateSeries(const Node: ICreateSeriesNode): IAstNode;
begin
    Result := Node; // Leaf node
end;

function TAstTransformer.VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode;
var
    N: TAddSeriesItemNode;
begin
    N := (Node as TAddSeriesItemNode);
    N.Series := Accept(N.Series).AsIdentifier;
    N.Value := Accept(N.Value);
    N.Lookback := Accept(N.Lookback); // Accept handles nil
    Result := Node;
end;

function TAstTransformer.VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode;
var
    N: TSeriesLengthNode;
begin
    N := (Node as TSeriesLengthNode);
    N.Series := Accept(N.Series).AsIdentifier;
    Result := Node;
end;

function TAstTransformer.VisitRecurNode(const Node: IRecurNode): IAstNode;
var
    N: TRecurNode;
begin
    N := (Node as TRecurNode);
    N.Arguments := AcceptNodes(N.Arguments);
    Result := Node;
end;

{ TAstVisitor }

function TAstVisitor.DoVisitConstant(const Node: IConstantNode): TDataValue;
begin
    VisitConstant(Node);
end;

function TAstVisitor.DoVisitIdentifier(const Node: IIdentifierNode): TDataValue;
begin
    VisitIdentifier(Node);
end;

function TAstVisitor.DoVisitKeyword(const Node: IKeywordNode): TDataValue;
begin
    VisitKeyword(Node);
end;

function TAstVisitor.DoVisitBinaryExpression(const Node: IBinaryExpressionNode): TDataValue;
begin
    VisitBinaryExpression(Node);
end;

function TAstVisitor.DoVisitUnaryExpression(const Node: IUnaryExpressionNode): TDataValue;
begin
    VisitUnaryExpression(Node);
end;

function TAstVisitor.DoVisitIfExpression(const Node: IIfExpressionNode): TDataValue;
begin
    VisitIfExpression(Node);
end;

function TAstVisitor.DoVisitTernaryExpression(const Node: ITernaryExpressionNode): TDataValue;
begin
    VisitTernaryExpression(Node);
end;

function TAstVisitor.DoVisitLambdaExpression(const Node: ILambdaExpressionNode): TDataValue;
begin
    VisitLambdaExpression(Node);
end;

function TAstVisitor.DoVisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
begin
    VisitFunctionCall(Node);
end;

function TAstVisitor.DoVisitMacroExpansionNode(const Node: IMacroExpansionNode): TDataValue;
begin
    VisitMacroExpansionNode(Node);
end;

function TAstVisitor.DoVisitBlockExpression(const Node: IBlockExpressionNode): TDataValue;
begin
    VisitBlockExpression(Node);
end;

function TAstVisitor.DoVisitVariableDeclaration(const Node: IVariableDeclarationNode): TDataValue;
begin
    VisitVariableDeclaration(Node);
end;

function TAstVisitor.DoVisitAssignment(const Node: IAssignmentNode): TDataValue;
begin
    VisitAssignment(Node);
end;

function TAstVisitor.DoVisitMacroDefinition(const Node: IMacroDefinitionNode): TDataValue;
begin
    VisitMacroDefinition(Node);
end;

function TAstVisitor.DoVisitQuasiquote(const Node: IQuasiquoteNode): TDataValue;
begin
    VisitQuasiquote(Node);
end;

function TAstVisitor.DoVisitUnquote(const Node: IUnquoteNode): TDataValue;
begin
    VisitUnquote(Node);
end;

function TAstVisitor.DoVisitUnquoteSplicing(const Node: IUnquoteSplicingNode): TDataValue;
begin
    VisitUnquoteSplicing(Node);
end;

function TAstVisitor.DoVisitIndexer(const Node: IIndexerNode): TDataValue;
begin
    VisitIndexer(Node);
end;

function TAstVisitor.DoVisitMemberAccess(const Node: IMemberAccessNode): TDataValue;
begin
    VisitMemberAccess(Node);
end;

function TAstVisitor.DoVisitRecordLiteral(const Node: IRecordLiteralNode): TDataValue;
begin
    VisitRecordLiteral(Node);
end;

function TAstVisitor.DoVisitCreateSeries(const Node: ICreateSeriesNode): TDataValue;
begin
    VisitCreateSeries(Node);
end;

function TAstVisitor.DoVisitAddSeriesItem(const Node: IAddSeriesItemNode): TDataValue;
begin
    VisitAddSeriesItem(Node);
end;

function TAstVisitor.DoVisitSeriesLength(const Node: ISeriesLengthNode): TDataValue;
begin
    VisitSeriesLength(Node);
end;

function TAstVisitor.DoVisitRecurNode(const Node: IRecurNode): TDataValue;
begin
    VisitRecurNode(Node);
end;

function TAstVisitor.DoVisitNop(const Node: INopNode): TDataValue;
begin
    // Added Nop implementation
    VisitNop(Node);
end;

end.