operator overloading 2

Smart pascal source code


type
  TMyStream = class
  end;

type
  TStreamSpecial = (BACKSPACE, CRLF);

function StreamString(s: TMyStream; str: String): TMyStream;
begin
  WriteLn(str);
  Result := s;
end;

operator << (TMyStream, String): TMyStream uses StreamString;

  function StreamSpecial(s: TMyStream; spec: TStreamSpecial): TMyStream;
  begin
    if spec = BACKSPACE then
      s << '<<'
    else
      s << #13#10;
    Result := s;
  end;

  operator << (TMyStream, TStreamSpecial): TMyStream uses StreamSpecial;

    function StreamDummy(s: TMyStream; str: String): TMyStream;
    begin
      s << 'Dummy ' << str << CRLF;
    end;

    operator >> (TMyStream, String): TMyStream uses StreamDummy;

    var   o := new TMyStream;

    o << " Hello world ! " << CRLF >> " Hey " << BACKSPACE <<
      " Wicked stuff .. ." << CRLF;

{<<< RESULT - CONSOLE LOG >>>
-----------------------------
Hello world!
Dummy Hey
<>>>>>>>>}

var TStreamSpecial = [ "BACKSPACE", "CRLF" ];
var TMyStream = {
   $ClassName:"TMyStream",$Parent:TObject
   ,$Init:function ($) {
      TObject.$Init($);
   }
   ,Destroy:TObject.Destroy
};
function StreamString(s, str) {
   var Result = null;
   WriteLn(str);
   Result = s;
   return Result
};
function StreamSpecial(s$1, spec) {
   var Result = null;
   if (!spec) {
      StreamString(s$1,"<<");
   } else {
      StreamString(s$1,"\r\n");
   }
   Result = s$1;
   return Result
};
function StreamDummy(s$2, str$1) {
   var Result = null;
   StreamSpecial(StreamString(StreamString(s$2,"Dummy "),str$1),1);
   return Result
};
var o = null;

/* <<< main JS >>> */

   o = TObject.Create($New(TMyStream));
   StreamSpecial(StreamString(StreamSpecial(StreamDummy(StreamSpecial(StreamString(o," Hello world ! "),1)," Hey "),0)," Wicked stuff .. ."),1);