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.