[SOLVED] Pass function as variable

[aradeonas]

Hi,
Is there any way to do this in FreePascal like Delphi( and I don't want to use prefix @)?

Code: [Select]

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;
  TCalcFunction = function(V1,V2:integer):integer;
var
  Form1: TForm1;

implementation

{$R *.lfm}
function SumFunction(V1,V2:integer):integer;
begin
  Result:=V1+V2;
end;
function Calculator(CalcFunction:TCalcFunction;V1,V2:integer):integer;
begin
 CalcFunction(V1,V2);
end;

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
begin
  ShowMessage(IntToStr(Calculator(@SumFunction,2,3)));
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  ShowMessage(IntToStr(Calculator(
  function SumFunction(V1,V2:integer):integer
  begin
       Result:=V1+V2;
  end
    ,1,2)));
end;

end.



[marcov]

change

Code: [Select]

{$mode objfpc}{$H+}

to

Code: [Select]

{$mode delphi}


[aradeonas]

I did that before and there is an error:

Code: [Select]

unit1.pas(50,3) Error: Illegal expression


[taazz]

Code: [Select]

unit Unit1;

{$mode objfpc}{$H+}


change the above to

Code: [Select]

{$mode DELPHI}{$H+}

That will eliminate the need to use @.

As for the anonymous method as far as I know fpc does not support them (yet?). You need to make it an internal function something like

Code: [Select]

procedure TForm1.Button2Click(Sender: TObject);
  function SumInternalFunction(V1,V2:integer):integer
  begin
       Result:=V1+V2;
  end
begin
  ShowMessage(IntToStr(Calculator(SumInternalFunction ,1,2)));
end;

should do the trick for you.

[aradeonas]

Thank you and I know that but in my situation I need to write cod like that and I want to sure there is no support for this in FreePascal.
http://forum.lazarus.freepascal.org/index.php/topic,26193.0.html
@marcov is there or not?

[marcov]

Indeed, no anonymous methods yet.  {$mode delphi} is mostly targeted at D7, and isn't compatible with e.g. the unicode side of D2009+ either.


Taaz: {$mode delphi} implies {$H+}

[aradeonas]

Thank you.