Initial check in rtl

src.rtl/ast/dpgrtl.astPair.pas

@@ -0,0 +1,64 @@
+unit dpgrtl.astPair;
+
+interface
+uses
+   dpgrtl.astBase;
+
+type
+   TASTPair = class
+      public
+         Root  : TAST;
+         Child : TAST;
+
+      public
+         procedure   AdvanceChildToEnd;
+         function    Clone: TASTPair;
+         function    ToString: string; override;
+
+   end;
+
+implementation
+
+{ TASTPair }
+
+// ================================================================================================
+// Advance Child To End
+// ================================================================================================
+procedure TASTPair.AdvanceChildToEnd;
+begin
+   if Assigned(Child) then
+      while Assigned( Child.NextSibling) do
+         Child := Child.NextSibling
+end;
+
+// ================================================================================================
+// Clone
+// ================================================================================================
+function TASTPair.Clone: TASTPair;
+begin
+   result       := TASTPair.Create;
+   result.Root  := Root;
+   result.Child := Child;
+end;
+
+// ================================================================================================
+// As String
+// ================================================================================================
+function TASTPair.ToString: string;
+var
+   r: string;
+   c: string;
+
+begin
+   if Assigned(Root)
+      then r := Root.ToString
+      else r := 'nil';
+
+   if Assigned(Child)
+      then c := Child.ToString
+      else c := 'nil';
+
+   result := '[' + r + ',' + c + ']'
+end;
+
+end.