Problem with parameter of procedural type

Pascal Script
1

Hi,
Is it possible to pass a parameter of procedural type from Pascal Script to the procedure of Delphi code? I thought that yes but…
There is the Pascal Script code:

program test;

procedure WindowSpecificAction(const wnd: HWND);
begin
    // some code here...
end;

begin
  ForEachWindow(@WindowSpecificAction);
end.

The procedure ForEachWindow defined in my Delphi code:

type
  TWindowSpecificAction = procedure(const wnd: HWND);

procedure ForEachWindow(Proc: TWindowSpecificAction);
var
  wnd : HWND;
begin
  //some code here...
  Assert(@Proc <> nil);  // EAssertionFailed with message 'Assertion failure...'
  Proc(wnd);
end;

...
ScriptCompiler.AddTypeS('TWindowSpecificAction', 'procedure (wnd: HWND)');
ScriptCompiler.AddDelphiFunction('procedure ForEachWindow(WindowSpecificAction: TWindowSpecificAction);');
ScriptInterpreter.RegisterDelphiFunction(@ForEachWindow, 'ForEachWindow', cdRegister);
...

And when the script executed I catched the exception.
Could you please show my mistake?
Thank you for advance.

Regards.

2

PascalScript only supports “of object” type method pointers, change it to that and it should work.

3

Thank you @ck!

I’ve changes signature of proc type:

type
  TWindowSpecificAction = procedure(const wnd: HWND) of object;

and

ScriptCompiler.AddTypeS('TWindowSpecificAction', 'procedure (wnd: HWND) of object;');

And now it’s works for me!
But is it OK? I’m not used objects in this code…

4

Yeah that’s fine. PascalScript puts stuff in the “self” to direct the call to the right place.