Macro expander integrated in binder

Src/AST/Myc.Ast.JSON.pas

@@ -24,7 +24,7 @@ type
     private
         FJsonObjectStack: TStack<TJSONObject>;
         procedure DataValueToJson(const AValue: TDataValue; const AParent: TJSONObject; const AName: string);
-        function JsonToNode(const AJson: TJSONValue): IAstNode;
+        function JsonToNode(const AJson: TJSONValue; const ExpectedType: String = ''): IAstNode;
         function JsonToDataValue(const AObj: TJSONObject; const AName: string): TDataValue;
 
         function JsonToConstantNode(const AObj: TJSONObject): IConstantNode;
@@ -276,7 +276,6 @@ var
     param: IIdentifierNode;
     i: Integer;
 begin
-    // Added serialization for macro definitions.
     Node.Name.Accept(Self);
     for param in Node.Parameters do
         param.Accept(Self);
@@ -719,7 +718,7 @@ function TJsonAstConverter.JsonToMacroDefNode(const AObj: TJSONObject): IMacroDe
 var
     name: IIdentifierNode;
     params: TArray<IIdentifierNode>;
-    body: IAstNode;
+    body: IQuasiquoteNode;
     paramArray: TJSONArray;
     i: Integer;
 begin
@@ -731,7 +730,7 @@ begin
     for i := 0 to paramArray.Count - 1 do
         params[i] := JsonToIdentifierNode(paramArray.Items[i] as TJSONObject);
 
-    body := JsonToNode(AObj.GetValue('Body'));
+    body := IQuasiquoteNode(JsonToNode(AObj.GetValue('Body'), 'Quasiquote'));
     Result := TAst.MacroDef(name, params, body);
 end;
 
@@ -874,7 +873,7 @@ begin
     Result := TAst.SeriesLength(JsonToIdentifierNode(AObj.GetValue('Series') as TJSONObject));
 end;
 
-function TJsonAstConverter.JsonToNode(const AJson: TJSONValue): IAstNode;
+function TJsonAstConverter.JsonToNode(const AJson: TJSONValue; const ExpectedType: String = ''): IAstNode;
 var
     obj: TJSONObject;
     nodeType: string;
@@ -885,6 +884,9 @@ begin
     obj := AJson as TJSONObject;
     nodeType := obj.GetValue<string>('NodeType');
 
+    if (ExpectedType <> '') and (nodeType <> ExpectedType) then
+        raise EInvalidCast.CreateFmt('Expected a JSON object of type %s for deserialization, but got a %s.', [ExpectedType, nodeType]);
+
     if nodeType = 'Constant' then
         Result := JsonToConstantNode(obj)
     else if nodeType = 'Identifier' then

Src/AST/Myc.Ast.Nodes.pas

@@ -200,11 +200,11 @@ type
         {$region 'private'}
         function GetName: IIdentifierNode;
         function GetParameters: TArray<IIdentifierNode>;
-        function GetBody: IAstNode;
+        function GetBody: IQuasiquoteNode;
         {$endregion}
         property Name: IIdentifierNode read GetName;
         property Parameters: TArray<IIdentifierNode> read GetParameters;
-        property Body: IAstNode read GetBody;
+        property Body: IQuasiquoteNode read GetBody;
     end;
 
     // Represents a quasiquoted expression, e.g., `(a b)

Src/AST/Myc.Ast.Script.pas

@@ -403,7 +403,11 @@ begin
 
                 var macroName := IIdentifierNode(tailNodes[0]);
                 var macroParams := elements[2].Params;
-                var macroBody := tailNodes[2];
+
+                if tailTokens[2].Kind <> tkQuote then
+                    raise Exception.Create('Syntax Error: Expected a quasiquote as macro body.');
+
+                var macroBody := IQuasiQuoteNode(tailNodes[2]);
 
                 Result := TAst.MacroDef(macroName, macroParams, macroBody);
             end

Src/AST/Myc.Ast.Visitor.pas

@@ -262,7 +262,7 @@ function TAstTransformer.VisitMacroDefinition(const Node: IMacroDefinitionNode):
 begin
     var name := Accept(Node.Name).AsIntf<IIdentifierNode>;
     var parameters := TransformNodes<IIdentifierNode>(Node.Parameters);
-    var body := Accept(Node.Body).AsIntf<IAstNode>;
+    var body := Accept(Node.Body).AsIntf<IQuasiquoteNode>;
     if (name = Node.Name) and (parameters = Node.Parameters) and (body = Node.Body) then
         Result := TDataValue.FromIntf<IMacroDefinitionNode>(Node)
     else

Src/AST/Myc.Ast.pas

@@ -39,7 +39,7 @@ type
         class function MacroDef(
             const AName: IIdentifierNode;
             const AParameters: TArray<IIdentifierNode>;
-            const ABody: IAstNode
+            const ABody: IQuasiquoteNode
         ): IMacroDefinitionNode; static;
         class function Quasiquote(const AExpression: IAstNode): IQuasiquoteNode; static;
         class function Unquote(const AExpression: IAstNode): IUnquoteNode; static;
@@ -158,12 +158,12 @@ type
     private
         FName: IIdentifierNode;
         FParameters: TArray<IIdentifierNode>;
-        FBody: IAstNode;
+        FBody: IQuasiquoteNode;
         function GetName: IIdentifierNode;
         function GetParameters: TArray<IIdentifierNode>;
-        function GetBody: IAstNode;
+        function GetBody: IQuasiquoteNode;
     public
-        constructor Create(const AName: IIdentifierNode; const AParameters: TArray<IIdentifierNode>; const ABody: IAstNode);
+        constructor Create(const AName: IIdentifierNode; const AParameters: TArray<IIdentifierNode>; const ABody: IQuasiquoteNode);
         function Accept(const Visitor: IAstVisitor): TDataValue; override;
         property Name: IIdentifierNode read GetName;
     end;
@@ -494,7 +494,11 @@ end;
 
 { TMacroDefinitionNode }
 
-constructor TMacroDefinitionNode.Create(const AName: IIdentifierNode; const AParameters: TArray<IIdentifierNode>; const ABody: IAstNode);
+constructor TMacroDefinitionNode.Create(
+    const AName: IIdentifierNode;
+    const AParameters: TArray<IIdentifierNode>;
+    const ABody: IQuasiquoteNode
+);
 begin
     inherited Create;
     FName := AName;
@@ -507,7 +511,7 @@ begin
     Result := Visitor.VisitMacroDefinition(Self);
 end;
 
-function TMacroDefinitionNode.GetBody: IAstNode;
+function TMacroDefinitionNode.GetBody: IQuasiquoteNode;
 begin
     Result := FBody;
 end;
@@ -927,7 +931,7 @@ end;
 class function TAst.MacroDef(
     const AName: IIdentifierNode;
     const AParameters: TArray<IIdentifierNode>;
-    const ABody: IAstNode
+    const ABody: IQuasiquoteNode
 ): IMacroDefinitionNode;
 begin
     Result := TMacroDefinitionNode.Create(AName, AParameters, ABody);