Ast node delete

ASTPlayground/ASTPlayground.dpr

@@ -31,7 +31,8 @@ uses
     Myc.Fmx.AstEditor.Workspace in '..\Src\AST\Myc.Fmx.AstEditor.Workspace.pas',
     Myc.Fmx.AstEditor.Layout in '..\Src\AST\Myc.Fmx.AstEditor.Layout.pas',
     Myc.Fmx.AstEditor.Node in '..\Src\AST\Myc.Fmx.AstEditor.Node.pas',
-    Myc.Fmx.AstEditor in '..\Src\AST\Myc.Fmx.AstEditor.pas';
+    Myc.Fmx.AstEditor in '..\Src\AST\Myc.Fmx.AstEditor.pas',
+    Myc.Ast.Refactoring.Remove in '..\Src\AST\Myc.Ast.Refactoring.Remove.pas';
 
 {$R *.res}
 

ASTPlayground/ASTPlayground.dproj

@@ -162,6 +162,7 @@
         <DCCReference Include="..\Src\AST\Myc.Fmx.AstEditor.Layout.pas"/>
         <DCCReference Include="..\Src\AST\Myc.Fmx.AstEditor.Node.pas"/>
         <DCCReference Include="..\Src\AST\Myc.Fmx.AstEditor.pas"/>
+        <DCCReference Include="..\Src\AST\Myc.Ast.Refactoring.Remove.pas"/>
         <BuildConfiguration Include="Base">
             <Key>Base</Key>
         </BuildConfiguration>

Src/AST/Myc.Ast.Refactoring.Remove.pas

@@ -0,0 +1,429 @@
+unit Myc.Ast.Refactoring.Remove;
+
+interface
+
+uses
+    System.SysUtils,
+    System.Classes,
+    System.Generics.Collections,
+    Myc.Ast,
+    Myc.Ast.Nodes,
+    Myc.Ast.Visitor,
+    Myc.Ast.Types;
+
+type
+    // Removes a specific node from the AST.
+    // - If the node is part of a list, it is removed from the list.
+    // - If the node is a mandatory child of a structure (e.g. If-Condition),
+    //   it is replaced by a Nop node to maintain tree integrity.
+    TAstNodeRemover = class(TAstTransformer)
+    private
+        FTarget: IAstNode;
+        FRemoved: Boolean;
+
+        // Generic helper to filter nil items from lists during transformation
+        function FilterList<T: IAstNode>(const Source: INodeList<T>): TArray<T>;
+
+        // Helper to ensure a mandatory slot is never nil (replaces with Nop)
+        function EnsureNode(const Node: IAstNode; const ContextNode: IAstNode): IAstNode;
+    protected
+        function Accept(const Node: IAstNode): IAstNode; override;
+
+        // --- List Containers (Filter Logic) ---
+        function VisitBlockExpression(const Node: IBlockExpressionNode): IAstNode; override;
+        function VisitExpressionList(const Node: IExpressionList): IAstNode; override;
+        function VisitArgumentList(const Node: IArgumentList): IAstNode; override;
+        function VisitParameterList(const Node: IParameterList): IAstNode; override;
+        function VisitRecordFieldList(const Node: IRecordFieldList): IAstNode; override;
+
+        // --- Structural Nodes (Replace Logic) ---
+        function VisitIfExpression(const Node: IIfExpressionNode): IAstNode; override;
+        function VisitTernaryExpression(const Node: ITernaryExpressionNode): IAstNode; override;
+        function VisitAssignment(const Node: IAssignmentNode): IAstNode; override;
+        function VisitVariableDeclaration(const Node: IVariableDeclarationNode): IAstNode; override;
+        function VisitLambdaExpression(const Node: ILambdaExpressionNode): IAstNode; override;
+        function VisitFunctionCall(const Node: IFunctionCallNode): IAstNode; override;
+        function VisitIndexer(const Node: IIndexerNode): IAstNode; override;
+        function VisitMemberAccess(const Node: IMemberAccessNode): IAstNode; override;
+        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode; override;
+
+    public
+        constructor Create(const ATarget: IAstNode);
+
+        // Tries to remove TargetNode from RootNode.
+        // Returns True if the node was found and removed/replaced.
+        // If successful, NewRootNode contains the modified AST.
+        // If not found, NewRootNode returns the original RootNode.
+        class function TryRemove(const RootNode, TargetNode: IAstNode; out NewRootNode: IAstNode): Boolean; static;
+    end;
+
+implementation
+
+{ TAstNodeRemover }
+
+constructor TAstNodeRemover.Create(const ATarget: IAstNode);
+begin
+    inherited Create;
+    FTarget := ATarget;
+    FRemoved := False;
+end;
+
+class function TAstNodeRemover.TryRemove(const RootNode, TargetNode: IAstNode; out NewRootNode: IAstNode): Boolean;
+var
+    Remover: TAstNodeRemover;
+begin
+    // Edge case: Removing the root itself
+    if (RootNode = TargetNode) then
+    begin
+        // We replace the root with a Nop, as we cannot return 'nil' for a valid AST root expectation usually
+        NewRootNode := TAst.Nop(RootNode.Identity);
+        Result := True;
+        Exit;
+    end;
+
+    Remover := TAstNodeRemover.Create(TargetNode);
+    try
+        NewRootNode := Remover.Accept(RootNode);
+        Result := Remover.FRemoved;
+
+        if not Result then
+        begin
+            // If nothing was removed, return the original node to ensure reference stability
+            NewRootNode := RootNode;
+        end
+        else if (NewRootNode = nil) then
+        begin
+            // Safety fallback: if traversal somehow resulted in nil (should be caught by EnsureNode logic usually)
+            NewRootNode := TAst.Nop(RootNode.Identity);
+        end;
+    finally
+        Remover.Free;
+    end;
+end;
+
+function TAstNodeRemover.Accept(const Node: IAstNode): IAstNode;
+begin
+    // If we matched the target, flag it as removed and return nil.
+    // The parent visitor is responsible for handling the nil result (Filter or Replace).
+    if Node = FTarget then
+    begin
+        FRemoved := True;
+        Exit(nil);
+    end;
+
+    Result := inherited Accept(Node);
+end;
+
+function TAstNodeRemover.EnsureNode(const Node: IAstNode; const ContextNode: IAstNode): IAstNode;
+begin
+    if Assigned(Node) then
+        Result := Node
+    else
+        // Mandatory child was deleted -> Replace with Nop using parent's identity location
+        Result := TAst.Nop(ContextNode.Identity);
+end;
+
+function TAstNodeRemover.FilterList<T>(const Source: INodeList<T>): TArray<T>;
+var
+    i: Integer;
+    item: T;
+    transformed: IAstNode;
+    list: TList<T>;
+begin
+    list := TList<T>.Create;
+    try
+        for i := 0 to Source.Count - 1 do
+        begin
+            item := Source[i];
+            transformed := Accept(item);
+
+            // If transformed is not nil, keep it.
+            // If it is nil, it was the target, so we skip (delete) it.
+            if Assigned(transformed) then
+                list.Add(T(transformed));
+        end;
+        Result := list.ToArray;
+    finally
+        list.Free;
+    end;
+end;
+
+// -----------------------------------------------------------------------------
+// List Visitors (Filtering)
+// -----------------------------------------------------------------------------
+
+function TAstNodeRemover.VisitBlockExpression(const Node: IBlockExpressionNode): IAstNode;
+var
+    newExprs: TArray<IAstNode>;
+    newList: IExpressionList;
+begin
+    newExprs := FilterList<IAstNode>(Node.Expressions);
+
+    // If counts differ, something was removed
+    if Length(newExprs) = Node.Expressions.Count then
+    begin
+        // If not marked as removed, we assume no change in this branch
+        if not FRemoved then
+            Exit(Node);
+
+        // Deep check for replacement
+        var changed := False;
+        for var i := 0 to High(newExprs) do
+            if newExprs[i] <> Node.Expressions[i] then
+                changed := True;
+
+        if not changed then
+            Exit(Node);
+    end;
+
+    newList := TExpressionList.Create(newExprs, Node.Expressions.Identity);
+    Result := TAst.Block(Node.Identity, newList, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitExpressionList(const Node: IExpressionList): IAstNode;
+var
+    newExprs: TArray<IAstNode>;
+begin
+    newExprs := FilterList<IAstNode>(Node);
+
+    if Length(newExprs) = Node.Count then
+    begin
+        var changed := False;
+        for var i := 0 to High(newExprs) do
+            if newExprs[i] <> Node[i] then
+                changed := True;
+        if not changed then
+            Exit(Node);
+    end;
+
+    Result := TExpressionList.Create(newExprs, Node.Identity);
+end;
+
+function TAstNodeRemover.VisitArgumentList(const Node: IArgumentList): IAstNode;
+var
+    newArgs: TArray<IAstNode>;
+begin
+    newArgs := FilterList<IAstNode>(Node);
+
+    if Length(newArgs) = Node.Count then
+    begin
+        var changed := False;
+        for var i := 0 to High(newArgs) do
+            if newArgs[i] <> Node[i] then
+                changed := True;
+        if not changed then
+            Exit(Node);
+    end;
+
+    Result := TArgumentList.Create(newArgs, Node.Identity);
+end;
+
+function TAstNodeRemover.VisitParameterList(const Node: IParameterList): IAstNode;
+var
+    newParams: TArray<IIdentifierNode>;
+begin
+    newParams := FilterList<IIdentifierNode>(Node);
+
+    if Length(newParams) = Node.Count then
+    begin
+        var changed := False;
+        for var i := 0 to High(newParams) do
+            if newParams[i] <> Node[i] then
+                changed := True;
+        if not changed then
+            Exit(Node);
+    end;
+
+    Result := TParameterList.Create(newParams, Node.Identity);
+end;
+
+function TAstNodeRemover.VisitRecordFieldList(const Node: IRecordFieldList): IAstNode;
+var
+    newFields: TArray<IRecordFieldNode>;
+begin
+    newFields := FilterList<IRecordFieldNode>(Node);
+
+    if Length(newFields) = Node.Count then
+    begin
+        var changed := False;
+        for var i := 0 to High(newFields) do
+            if newFields[i] <> Node[i] then
+                changed := True;
+        if not changed then
+            Exit(Node);
+    end;
+
+    Result := TRecordFieldList.Create(newFields, Node.Identity);
+end;
+
+// -----------------------------------------------------------------------------
+// Structural Visitors (Replacement with Nop/Void)
+// -----------------------------------------------------------------------------
+
+function TAstNodeRemover.VisitIfExpression(const Node: IIfExpressionNode): IAstNode;
+var
+    newCond, newThen, newElse: IAstNode;
+begin
+    newCond := Accept(Node.Condition);
+    newThen := Accept(Node.ThenBranch);
+    newElse := Accept(Node.ElseBranch);
+
+    // If condition or Then-branch is deleted, replace with Nop
+    newCond := EnsureNode(newCond, Node);
+    newThen := EnsureNode(newThen, Node);
+
+    // Else branch is optional
+    if (newCond = Node.Condition) and (newThen = Node.ThenBranch) and (newElse = Node.ElseBranch) then
+        Exit(Node);
+
+    Result := TAst.IfExpr(Node.Identity, newCond, newThen, newElse, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitTernaryExpression(const Node: ITernaryExpressionNode): IAstNode;
+var
+    newCond, newThen, newElse: IAstNode;
+begin
+    newCond := EnsureNode(Accept(Node.Condition), Node);
+    newThen := EnsureNode(Accept(Node.ThenBranch), Node);
+    newElse := EnsureNode(Accept(Node.ElseBranch), Node);
+
+    if (newCond = Node.Condition) and (newThen = Node.ThenBranch) and (newElse = Node.ElseBranch) then
+        Exit(Node);
+
+    Result := TAst.TernaryExpr(Node.Identity, newCond, newThen, newElse, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitAssignment(const Node: IAssignmentNode): IAstNode;
+var
+    newTarget, newValue: IAstNode;
+begin
+    newTarget := EnsureNode(Accept(Node.Target), Node);
+    newValue := EnsureNode(Accept(Node.Value), Node);
+
+    if (newTarget = Node.Target) and (newValue = Node.Value) then
+        Exit(Node);
+
+    Result := TAst.Assign(Node.Identity, newTarget, newValue, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitVariableDeclaration(const Node: IVariableDeclarationNode): IAstNode;
+var
+    newTarget, newInit: IAstNode;
+begin
+    newTarget := EnsureNode(Accept(Node.Target), Node);
+    newInit := Accept(Node.Initializer); // Initializer is optional
+
+    if (newTarget = Node.Target) and (newInit = Node.Initializer) then
+        Exit(Node);
+
+    Result := TAst.VarDecl(Node.Identity, newTarget, newInit, Node.StaticType, Node.IsBoxed);
+end;
+
+function TAstNodeRemover.VisitLambdaExpression(const Node: ILambdaExpressionNode): IAstNode;
+var
+    newParams: IAstNode;
+    newBody: IAstNode;
+begin
+    newParams := Accept(Node.Parameters);
+    // If the parameter list itself was the target, we replace it with an empty list
+    if newParams = nil then
+        newParams := TParameterList.Create([], Node.Parameters.Identity);
+
+    newBody := EnsureNode(Accept(Node.Body), Node);
+
+    if (newParams = Node.Parameters) and (newBody = Node.Body) then
+        Exit(Node);
+
+    Result :=
+        TAst.LambdaExpr(
+            Node.Identity,
+            newParams.AsParameterList,
+            newBody,
+            Node.Layout,
+            Node.Descriptor,
+            Node.Upvalues,
+            Node.HasNestedLambdas,
+            Node.IsPure,
+            Node.StaticType
+        );
+end;
+
+function TAstNodeRemover.VisitFunctionCall(const Node: IFunctionCallNode): IAstNode;
+var
+    newCallee: IAstNode;
+    newArgs: IAstNode;
+begin
+    newCallee := EnsureNode(Accept(Node.Callee), Node);
+
+    newArgs := Accept(Node.Arguments);
+    if newArgs = nil then
+        newArgs := TArgumentList.Create([], Node.Arguments.Identity);
+
+    if (newCallee = Node.Callee) and (newArgs = Node.Arguments) then
+        Exit(Node);
+
+    Result :=
+        TAst.FunctionCall(
+            Node.Identity,
+            newCallee,
+            newArgs.AsArgumentList,
+            Node.StaticType,
+            Node.IsTailCall,
+            Node.StaticTarget,
+            Node.IsTargetPure
+        );
+end;
+
+function TAstNodeRemover.VisitIndexer(const Node: IIndexerNode): IAstNode;
+var
+    newBase, newIndex: IAstNode;
+begin
+    newBase := EnsureNode(Accept(Node.Base), Node);
+    newIndex := EnsureNode(Accept(Node.Index), Node);
+
+    if (newBase = Node.Base) and (newIndex = Node.Index) then
+        Exit(Node);
+
+    Result := TAst.Indexer(Node.Identity, newBase, newIndex, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitMemberAccess(const Node: IMemberAccessNode): IAstNode;
+var
+    newBase: IAstNode;
+    newMember: IAstNode;
+begin
+    newBase := EnsureNode(Accept(Node.Base), Node);
+
+    newMember := Accept(Node.Member);
+    if newMember = nil then
+    begin
+        // If member name is deleted, the access is invalid. Replace whole node with Nop.
+        Exit(TAst.Nop(Node.Identity));
+    end;
+
+    if (newBase = Node.Base) and (newMember = Node.Member) then
+        Exit(Node);
+
+    Result := TAst.MemberAccess(Node.Identity, newBase, newMember.AsKeyword, Node.StaticType);
+end;
+
+function TAstNodeRemover.VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode;
+var
+    newSeries: IAstNode;
+    newValue: IAstNode;
+    newLookback: IAstNode;
+begin
+    newSeries := Accept(Node.Series);
+    if newSeries = nil then
+        Exit(TAst.Nop(Node.Identity)); // Cannot exist without series identifier
+
+    newValue := EnsureNode(Accept(Node.Value), Node);
+    newLookback := Accept(Node.Lookback); // Optional
+
+    if (newSeries = Node.Series) and (newValue = Node.Value) and (newLookback = Node.Lookback) then
+        Exit(Node);
+
+    Result := TAst.AddSeriesItem(Node.Identity, newSeries.AsIdentifier, newValue, newLookback, Node.StaticType);
+end;
+
+end.

Src/AST/Myc.Fmx.AstEditor.pas

@@ -20,6 +20,7 @@ uses
     Myc.Ast.Visitor,
     Myc.Ast.Scope,
     Myc.Ast.Environment,
+    Myc.Ast.Refactoring.Remove,
     Myc.Fmx.AstEditor.Node,
     Myc.Fmx.AstEditor.Layout,
     Myc.Fmx.AstEditor.Workspace;
@@ -71,8 +72,6 @@ type
         procedure HandleKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char; Shift: TShiftState);
         procedure HandleWorkspacePaintConnections(ASender: TObject; ACanvas: TCanvas);
         procedure HandleWorkspaceMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
-
-        // NEU: Handler für Klicks auf die Nodes selbst
         procedure HandleNodeMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
 
         procedure CommitSnapshot;
@@ -99,7 +98,9 @@ type
         procedure Init(const AEnv: TAstEnvironment);
 
         procedure ValidateAndShow;
-        procedure SetRoot(const AstNode: IAstNode);
+
+        // AClearHistory=False ensures stacks are kept (e.g. after internal edits)
+        procedure SetRoot(const AstNode: IAstNode; AClearHistory: Boolean = True);
 
         procedure Undo;
         procedure Redo;
@@ -201,32 +202,21 @@ end;
 
 procedure TAstEditor.HandleWorkspaceMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
 begin
-    // Wenn wir in den leeren Bereich klicken:
-    // 1. Tastaturfokus sicherstellen (wichtig!)
     if FWorkspace.CanFocus then
         FWorkspace.SetFocus;
 
-    // Optional: Fokus löschen, wenn man ins Leere klickt?
-    // SetFocusedNode(nil); // Geschmackssache. Viele Editoren behalten den Fokus.
-
     if Assigned(FOnWorkspaceMouseDown) then
         FOnWorkspaceMouseDown(Self, Button, Shift, X, Y);
 end;
 
 procedure TAstEditor.HandleNodeMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single);
 begin
-    // 1. Fokus für Navigation sicherstellen (Keyboard Events gehen an Workspace)
     if FWorkspace.CanFocus then
         FWorkspace.SetFocus;
 
-    // 2. Visuellen/Logischen Node-Fokus setzen
     if (Button = TMouseButton.mbLeft) and (Sender is TAstViewNode) then
     begin
         SetFocusedNode(TAstViewNode(Sender));
-
-        // Stoppt die Event-Propagation nach oben zum Workspace, damit wir nicht
-        // sofort wieder deselektieren (falls wir das im WorkspaceMouseDown implementiert hätten).
-        // TControl.MouseDown hat kein 'Handled', aber wir sind hier im Event-Handler.
     end;
 end;
 
@@ -252,7 +242,7 @@ begin
             FRedoStack.Push(FCurrentAst);
 
         prevAst := FUndoStack.Pop;
-        SetRoot(prevAst);
+        SetRoot(prevAst); // Default Clear=True, but guarded by FIsUndoing
     finally
         FIsUndoing := False;
     end;
@@ -332,17 +322,62 @@ begin
                 CommitSnapshot;
                 Reorderable.MoveChild(SourceIdx, TargetIdx);
                 NewAst := FRootViewNode.CreateAst;
-                SetRoot(NewAst);
 
-                // Optional: Fokus auf den verschobenen Node wiederherstellen
+                // IMPORTANT: Pass False to preserve the undo stack we just updated
-                // Da der Node neu erzeugt wurde, müssten wir ihn über die Identity suchen.
+                SetRoot(NewAst, False);
             end;
         end;
     end;
 end;
 
 procedure TAstEditor.HandleKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char; Shift: TShiftState);
+var
+    NewRoot: IAstNode;
 begin
+    // Undo / Redo Handling
+    if (ssCtrl in Shift) then
+    begin
+        if (Key = vkZ) then
+        begin
+            if (ssShift in Shift) then
+            begin
+                if CanRedo then
+                    Redo;
+            end
+            else
+            begin
+                if CanUndo then
+                    Undo;
+            end;
+            Key := 0;
+            Exit;
+        end
+        else if (Key = vkY) then
+        begin
+            if CanRedo then
+                Redo;
+            Key := 0;
+            Exit;
+        end;
+    end;
+
+    // Delete Handling
+    if (Key = vkDelete) then
+    begin
+        if Assigned(FFocusedNode) and Assigned(FFocusedNode.Node) and Assigned(FCurrentAst) then
+        begin
+            CommitSnapshot;
+            if TAstNodeRemover.TryRemove(FCurrentAst, FFocusedNode.Node, NewRoot) then
+            begin
+                // IMPORTANT: Pass False to preserve the undo stack we just updated
+                SetRoot(NewRoot, False);
+            end;
+        end;
+        Key := 0;
+        Exit;
+    end;
+
+    // Navigation
     if Key in [vkLeft, vkRight, vkUp, vkDown, vkTab, vkEscape] then
     begin
         Navigate(Key, Shift);
@@ -350,13 +385,14 @@ begin
     end;
 end;
 
-procedure TAstEditor.SetRoot(const AstNode: IAstNode);
+procedure TAstEditor.SetRoot(const AstNode: IAstNode; AClearHistory: Boolean);
 var
     Visualizer: IAstVisualizer;
 begin
     FCurrentAst := AstNode;
 
-    if not FIsUndoing then
+    // Only clear if explicitly requested AND not currently performing an undo/redo
+    if AClearHistory and (not FIsUndoing) then
     begin
         FUndoStack.Clear;
         FRedoStack.Clear;
@@ -401,8 +437,6 @@ begin
             if child is TAstViewNode then
             begin
                 viewNode := TAstViewNode(child);
-
-                // HIER: Das Click-Event wiring
                 viewNode.OnMouseDown := HandleNodeMouseDown;
 
                 if Assigned(viewNode.Node) and Assigned(viewNode.Node.Identity) then
@@ -529,7 +563,7 @@ end;
 
 procedure TAstEditor.EnsureVisible(Node: TAstViewNode);
 const
-    cMargin = 40; // Abstand zum Rand in Pixeln
+    cMargin = 40;
 var
     NodeRect, ViewRect: TRectF;
     Delta: TPointF;
@@ -537,50 +571,26 @@ begin
     if (Node = nil) or (FWorkspace = nil) then
         Exit;
 
-    // 1. Hole absolute Koordinaten
     NodeRect := Node.AbsoluteRect;
     ViewRect := FWorkspace.AbsoluteRect;
-
-    // 2. Definiere den "sicheren" Bereich (Viewport minus Rand)
     ViewRect.Inflate(-cMargin, -cMargin);
 
     Delta := TPointF.Zero;
 
-    // 3. Horizontal prüfen
     if NodeRect.Width > ViewRect.Width then
-    begin
+        Delta.X := ViewRect.CenterPoint.X - NodeRect.CenterPoint.X
-        // Node ist breiter als der Screen -> Zentrieren
-        Delta.X := ViewRect.CenterPoint.X - NodeRect.CenterPoint.X;
-    end
     else if NodeRect.Left < ViewRect.Left then
-    begin
+        Delta.X := ViewRect.Left - NodeRect.Left
-        // Node ragt links raus -> nach rechts schieben
-        Delta.X := ViewRect.Left - NodeRect.Left;
-    end
     else if NodeRect.Right > ViewRect.Right then
-    begin
-        // Node ragt rechts raus -> nach links schieben
         Delta.X := ViewRect.Right - NodeRect.Right;
-    end;
 
-    // 4. Vertikal prüfen
     if NodeRect.Height > ViewRect.Height then
-    begin
+        Delta.Y := ViewRect.CenterPoint.Y - NodeRect.CenterPoint.Y
-        // Node ist höher als der Screen -> Zentrieren
-        Delta.Y := ViewRect.CenterPoint.Y - NodeRect.CenterPoint.Y;
-    end
     else if NodeRect.Top < ViewRect.Top then
-    begin
+        Delta.Y := ViewRect.Top - NodeRect.Top
-        // Node ragt oben raus -> nach unten schieben
-        Delta.Y := ViewRect.Top - NodeRect.Top;
-    end
     else if NodeRect.Bottom > ViewRect.Bottom then
-    begin
-        // Node ragt unten raus -> nach oben schieben
         Delta.Y := ViewRect.Bottom - NodeRect.Bottom;
-    end;
 
-    // 5. Nur anwenden, wenn eine Verschiebung nötig ist
     if not (SameValue(Delta.X, 0, TEpsilon.Position) and SameValue(Delta.Y, 0, TEpsilon.Position)) then
     begin
         FWorkspace.ContentOffset := FWorkspace.ContentOffset + Delta;
@@ -674,8 +684,6 @@ begin
     end;
 end;
 
-// Helper um den nächsten ViewNode in einer Liste von Controls zu finden
-
 function FindNextSiblingInList(Parent: TControl; AfterControl: TControl): TAstViewNode;
 var
     i, StartIndex: Integer;
@@ -740,8 +748,6 @@ begin
     end;
 end;
 
-// --- Vertical Axis Navigation (Skip Row) ---
-
 function TAstEditor.GetNextVerticalNeighbor(StartNode: TAstViewNode): TAstViewNode;
 var
     Current, Parent: TControl;
@@ -755,7 +761,6 @@ begin
         if Parent = nil then
             Break;
 
-        // Wenn der Parent vertikal ist, suchen wir hier den Nachbarn.
         if (Parent is TAutoFitControl) and (TAutoFitControl(Parent).Orientation = TLayoutOrientation.loVertical) then
         begin
             Result := FindNextSiblingInList(Parent, Current);
@@ -803,12 +808,10 @@ var
     i, StartIndex: Integer;
     Candidate: TControl;
 begin
-    // 1. Try Child (Drill Down)
     Result := GetFirstChild(StartNode);
     if Result <> nil then
         Exit;
 
-    // 2. Walk up visually and check for next siblings at every layout level
     CurrentControl := StartNode;
     while (CurrentControl <> nil) and (CurrentControl <> FWorkspace.World) do
     begin
@@ -816,7 +819,6 @@ begin
         if ParentControl = nil then
             Break;
 
-        // Find index of current control
         StartIndex := -1;
         for i := 0 to ParentControl.ChildrenCount - 1 do
             if ParentControl.Children[i] = CurrentControl then
@@ -825,7 +827,6 @@ begin
                 Break;
             end;
 
-        // Scan forward from next index
         if StartIndex >= 0 then
         begin
             for i := StartIndex + 1 to ParentControl.ChildrenCount - 1 do
@@ -835,7 +836,6 @@ begin
                     Candidate := TControl(ParentControl.Children[i]);
                     if Candidate.Visible then
                     begin
-                        // Check if this candidate IS a node or CONTAINS a node
                         Result := FindFirstViewNode(Candidate);
                         if Result <> nil then
                             Exit;
@@ -844,7 +844,6 @@ begin
             end;
         end;
 
-        // Move up one physical level (e.g. from ParameterList to TitleContainer)
         CurrentControl := ParentControl;
     end;
 
@@ -857,12 +856,6 @@ var
     i, StartIndex: Integer;
     Candidate: TControl;
 begin
-    // No simple "Drill Down" here, because Prev means "Left of me".
-    // If I have children, "Left of me" is OUTSIDE of me (Parent or Sibling).
-    // Wait: Standard Tab behavior:
-    // Tab: Current -> Child -> Next Sibling
-    // Shift-Tab: Current -> Prev Sibling (Deepest Child) -> Parent
-
     CurrentControl := StartNode;
     while (CurrentControl <> nil) and (CurrentControl <> FWorkspace.World) do
     begin
@@ -870,7 +863,6 @@ begin
         if ParentControl = nil then
             Break;
 
-        // Find index
         StartIndex := -1;
         for i := 0 to ParentControl.ChildrenCount - 1 do
             if ParentControl.Children[i] = CurrentControl then
@@ -879,7 +871,6 @@ begin
                 Break;
             end;
 
-        // Scan backward
         if StartIndex >= 0 then
         begin
             for i := StartIndex - 1 downto 0 do
@@ -889,7 +880,6 @@ begin
                     Candidate := TControl(ParentControl.Children[i]);
                     if Candidate.Visible then
                     begin
-                        // Find the deepest last node inside this sibling
                         Result := FindLastViewNode(Candidate);
                         if Result <> nil then
                             Exit;
@@ -898,19 +888,15 @@ begin
             end;
         end;
 
-        // If no sibling found to the left, the Parent is the previous logical node
         if ParentControl is TAstViewNode then
             Exit(TAstViewNode(ParentControl));
 
-        // If Parent is just a Layout Container, keep walking up
         CurrentControl := ParentControl;
     end;
 
     Result := nil;
 end;
 
-// --- Main Navigate Method ---
-
 procedure TAstEditor.Navigate(Key: Word; Shift: TShiftState);
 var
     Current: TAstViewNode;
@@ -925,7 +911,6 @@ begin
     Current := FFocusedNode;
     Target := nil;
 
-    // 1. Linear Navigation (Tab) - Bleibt wie gehabt
     if Key = vkTab then
     begin
         if ssShift in Shift then
@@ -938,7 +923,6 @@ begin
         Exit;
     end;
 
-    // 2. Escape - Bleibt "Notausgang" zum Parent
     if Key = vkEscape then
     begin
         Target := GetParentNode(Current);
@@ -947,27 +931,11 @@ begin
         Exit;
     end;
 
-    // 3. Axis Analysis
     case Key of
-        vkLeft:
+        vkLeft: Target := GetPrevLinearNode(Current);
-        begin
+        vkRight: Target := GetNextLinearNode(Current);
-            Target := GetPrevLinearNode(Current);
+        vkUp: Target := GetPrevVerticalNeighbor(Current);
-        end;
+        vkDown: Target := GetNextVerticalNeighbor(Current);
-
-        vkRight:
-        begin
-            Target := GetNextLinearNode(Current);
-        end;
-
-        vkUp:
-        begin
-            Target := GetPrevVerticalNeighbor(Current)
-        end;
-
-        vkDown:
-        begin
-            Target := GetNextVerticalNeighbor(Current)
-        end;
     end;
 
     if Target <> nil then