Smart pascal source code


type
  TBase = class
end;

type
  TChild = class(TBase)
end;

{ main.pas }
var
  o := TObject.Create;
  c := TChild.Create;

Begin
  Writeln(TObject(o).ClassName);
  Writeln(TObject(c).ClassName);

  Writeln((o as TObject).ClassName);
  Writeln((c as TObject).ClassName);

  try   
    Writeln(TChild(c).ClassName);
    Writeln(TChild(o).ClassName);
  except   
   on E: Exception do
    Writeln(E.Message);
  end;

  try   
    Writeln((c as TChild).ClassName);
    Writeln((o as TChild).ClassName);
  except   
    on E: Exception do
    Writeln(E.Message);
  end;

{ ### CONSOLE OUTPUTS ###
  TObject
  TChild
  TObject
  TChild
  TChild
  Cannot cast instance of type "TObject" to class "TChild"
  TChild
  Cannot cast instance of type "TObject" to class "TChild"

}

var Exception={
	$ClassName: "Exception",
	$Parent: TObject,
	$Init: function () { FMessage="" },
	Create: function (s,Msg) { s.FMessage=Msg; return s }
}
function $W(e) { return e.ClassType?e:Exception.Create($New(Exception),e.constructor.name+", "+e.message) }
function $ToClassType(o) {
	if (o===null) return o;
	return o.ClassType
};
function $New(c) { var i={ClassType:c}; c.$Init(i); return i }
function $Is(o,c) {
	if (o===null) return false;
	return $Inh(o.ClassType,c);
};
function $Inh(s,c) {
	if (s===null) return false;
	while ((s)&&(s!==c)) s=s.$Parent;
	return (s)?true:false;
};
function $As(o,c) {
	if ((o===null)||$Is(o,c)) return o;
	throw Exception.Create($New(Exception),"Cannot cast instance of type \""+o.ClassType.$ClassName+"\" to class \""+c.$ClassName+"\"");
}
      var o = null,
         o = TObject.Create($New(TObject));
      var c = null,
         c = TObject.Create($New(TChild));
      WriteLn(ClassName$1($ToClassType(o)));
      WriteLn(ClassName$1($ToClassType(c)));
      WriteLn(ClassName$1($ToClassType(o)));
      WriteLn(ClassName$1($ToClassType(c)));
      try {
         WriteLn(ClassName$1($ToClassType(c)));
         WriteLn(ClassName$1($ToClassType($As(o,TChild))));
      } catch ($e) {
         var E = $W($e);
         WriteLn(E.FMessage)      }
      try {
         WriteLn(ClassName$1($ToClassType(c)));
         WriteLn(ClassName$1($ToClassType($As(o,TChild))));
      } catch ($e) {
         var E$1 = $W($e);
         WriteLn(E$1.FMessage)      }
   }

/// TBase = class (TObject)
///  [line: 72, column: 3, file: uMain]
var TBase = {
   $ClassName:"TBase",$Parent:TObject
   ,$Init:function ($) {
      TObject.$Init($);
   }
   ,Destroy:TObject.Destroy
};
/// TChild = class (TBase)
///  [line: 76, column: 3, file: uMain]
var TChild = {
   $ClassName:"TChild",$Parent:TBase
   ,$Init:function ($) {
      TBase.$Init($);
   }
   ,Destroy:TObject.Destroy
};