AST Debugger

Src/AST/Myc.Ast.Debugger.pas

@@ -13,26 +13,6 @@ uses
     Myc.Ast.Evaluator;
 
 type
-    TDebugSession = class
-    private
-        class var
-            FCurrent: TDebugSession;
-    private
-        FLog: TStrings;
-        FShowScope: Boolean;
-        FVisitorStack: TStack<IAstVisitor>;
-        function GetLog: TStrings;
-    public
-        constructor Create(AShowScope: Boolean);
-        destructor Destroy; override;
-
-        class property Current: TDebugSession read FCurrent;
-
-        function Execute(const ANode: IAstNode; const AScriptScope: IExecutionScope): TDataValue;
-        property Log: TStrings read GetLog;
-        property VisitorStack: TStack<IAstVisitor> read FVisitorStack;
-    end;
-
     TDebugEvaluatorVisitor = class(TEvaluatorVisitor)
     private
         FLog: TStrings;
@@ -44,9 +24,18 @@ type
         procedure ShowScope;
     protected
         // Overridden to provide the debug-specific visitor factory.
-        function GetVisitorFactory: TVisitorFactory; override;
+        function CreateVisitorFactory: TVisitorFactory; override;
+
     public
         constructor Create(const AScope: IExecutionScope; ALog: TStrings; AShowScope: Boolean; AInitialIndent: Integer = 0);
+
+        class function CreateVisitor(
+            const AScope: IExecutionScope;
+            ALog: TStrings;
+            AShowScope: Boolean;
+            AInitialIndent: Integer = 0
+        ): IAstVisitor;
+
         function VisitFunctionCall(const Node: IFunctionCallNode): TDataValue; override;
         // The logging overrides for other Visit... methods
         function VisitConstant(const Node: IConstantNode): TDataValue; override;
@@ -71,44 +60,9 @@ uses
     System.TypInfo,
     Myc.Ast.Printer;
 
-{ TDebugSession }
-
-constructor TDebugSession.Create(AShowScope: Boolean);
-begin
-    inherited Create;
-    if Assigned(FCurrent) then
-        raise EInvalidOpException.Create('Another debug session is already active.');
-
-    FLog := TStringList.Create;
-    FShowScope := AShowScope;
-    FVisitorStack := TStack<IAstVisitor>.Create;
-    FCurrent := Self;
-end;
-
-destructor TDebugSession.Destroy;
-begin
-    FLog.Free;
-    FVisitorStack.Free;
-    FCurrent := nil;
-    inherited Destroy;
-end;
-
-function TDebugSession.Execute(const ANode: IAstNode; const AScriptScope: IExecutionScope): TDataValue;
-var
-    initialVisitor: IAstVisitor;
-begin
-    initialVisitor := TDebugEvaluatorVisitor.Create(AScriptScope, FLog, FShowScope, 0);
-    Result := ANode.Accept(initialVisitor);
-end;
-
-function TDebugSession.GetLog: TStrings;
-begin
-    Result := FLog;
-end;
-
 { TDebugEvaluatorVisitor }
 
-constructor TDebugEvaluatorVisitor.Create(const AScope: IExecutionScope; ALog: TStrings; AShowScope: Boolean; AInitialIndent: Integer);
+constructor TDebugEvaluatorVisitor.Create(const AScope: IExecutionScope; ALog: TStrings; AShowScope: Boolean; AInitialIndent: Integer = 0);
 begin
     inherited Create(AScope);
     Assert(Assigned(ALog));
@@ -118,41 +72,32 @@ begin
     ShowScope;
 end;
 
-function TDebugEvaluatorVisitor.GetVisitorFactory: TVisitorFactory;
+function TDebugEvaluatorVisitor.CreateVisitorFactory: TVisitorFactory;
 begin
-    // Return a closure that creates a new Debug visitor,
-    // using the context from the currently active session stack.
+    // Return a closure that creates a new Debug visitor, using the current context
+
+    var callingVisitor := Self as IAstVisitor;
     Result :=
         function(const AScope: IExecutionScope): IAstVisitor
         begin
-            if (not Assigned(TDebugSession.Current)) or (TDebugSession.Current.VisitorStack.Count = 0) then
-                raise EInvalidOpException.Create('Visitor stack is empty during function invocation.');
-
-            var callingVisitor := TDebugSession.Current.VisitorStack.Peek as TDebugEvaluatorVisitor;
-            Result := TDebugEvaluatorVisitor.Create(AScope, callingVisitor.FLog, callingVisitor.FShowScope, callingVisitor.FIndentLevel);
+            var visitor := callingVisitor as TDebugEvaluatorVisitor;
+            Result := TDebugEvaluatorVisitor.Create(AScope, visitor.FLog, visitor.FShowScope, visitor.FIndentLevel);
         end;
 end;
 
 function TDebugEvaluatorVisitor.VisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
 begin
-    Assert(Assigned(TDebugSession.Current), 'No active debug session.');
-    TDebugSession.Current.VisitorStack.Push(Self);
+    AppendLine('FunctionCall{');
+    Indent;
     try
-        AppendLine('FunctionCall{');
-        Indent;
-        try
-            ShowScope;
-            Result := inherited VisitFunctionCall(Node);
-        finally
-            Unindent;
-        end;
-        AppendLine(Format('} -> %s', [Result.ToString]));
+        ShowScope;
+        Result := inherited VisitFunctionCall(Node);
     finally
-        TDebugSession.Current.VisitorStack.Pop;
+        Unindent;
     end;
+    AppendLine(Format('} -> %s', [Result.ToString]));
 end;
 
-// ... The rest of the TDebugEvaluatorVisitor logging methods are unchanged ...
 procedure TDebugEvaluatorVisitor.Indent;
 begin
     inc(FIndentLevel);
@@ -170,12 +115,20 @@ var
 begin
     pad := '';
     for i := 0 to FIndentLevel - 1 do
-    begin
         pad := pad + ':' + ''.PadLeft(3);
-    end;
     FLog.Add(pad + S);
 end;
 
+class function TDebugEvaluatorVisitor.CreateVisitor(
+    const AScope: IExecutionScope;
+    ALog: TStrings;
+    AShowScope: Boolean;
+    AInitialIndent: Integer = 0
+): IAstVisitor;
+begin
+    Result := TDebugEvaluatorVisitor.Create(AScope, ALog, AShowScope, AInitialIndent);
+end;
+
 procedure TDebugEvaluatorVisitor.ShowScope;
 var
     scopeDump: TArray<string>;