Hi

While reading a bug report I made the following experiment with Delphi 2009 and then with Lazarus + FPC 2.4.4.

TMainMenu.Items is of type TMenuItem. TMenuItem has only one version of "Add" method and it takes another TMenuItem as parameter (checked from VCL source).
Still, to my surprise, the code works in Delphi.

FPC says: Error: Incompatible type for arg no. 1: Got "Dynamic Array Of TMenuItem", expected "TMenuItem"
which is what I expected also from Delphi.

---
procedure TForm1.FormCreate(Sender: TObject);
var
  ma: array of TMenuItem;
  mi: TMenuItem;
begin
  SetLength(ma, 2);
  mi := TMenuItem.Create(MainMenu1);
  mi.Caption := 'File';
  ma[0] := mi;
  mi := TMenuItem.Create(MainMenu1);
  mi.Caption := 'Help';
  ma[1] := mi;
  MainMenu1.Items.add(ma); // Works in Delphi
end;
---

Is this a known issue?

Regards
Juha

It is always best to isolate such things in a self-contained example that does not depend on external code. Does this compile with your Delphi version?

***
type
  tc = class
  end;
procedure add(c: tc);
begin
end;
var
  a: array of tc;
begin
  add(a);
end.
***

If not, the issue is something else. It seems more likely to me that there is somewhere another "add" method that Delphi picks up but FPC doesn't. E.g., there is at least also "TComponent.Add(item : IUnknown) : Integer;". While that one won't accept a dynamic array, maybe Delphi 2009 has more add methods in TComponent declared with "overload" (although normally searching for overloads should stop as soon as a method is found in a class without "overload", so in principle the search should stop when tmenuitem.add is encountered).

If the above does compile, what does it actually do? Pass the first element of the array?

Jonas

Delphi has a procedure TMenuItem.Add(const AItems: array of TMenuItem); overload; which isn't implemented in Lazarus. It existed already in Delphi6. So, not a compiler issue.

Ludo

2011/8/13 Jonas Maebe

It is always best to isolate such things in a self-contained example that does not depend on external code. Does this compile with your Delphi version?

Yes, I should have done that. The code you gave does not compile.

If not, the issue is something else. It seems more likely to me that there

The original code which works in Delphi is interesting because it not only compiles but it also works perfectly, adding those 2 menuitems to mainmenu.

There is no TComponent.Add, neither in VCL nor LCL. I try to figure out what is happening...

Thanks for replying.

Juha

2011/8/13 Ludo Brands

Delphi has a procedure TMenuItem.Add(const AItems: array of TMenuItem); overload; which isn't implemented in Lazarus. It existed already in Delphi6. So, not a compiler issue.

Ludo, you are right. Somehow I missed it. Uhhh...
Ctrl-Click leads to the other "Add".
Problem solved.

I will add such method to LCL.

Juha

Related question, but the other way round. The following code does compile in FPC (didn't test Delphi). Is that by design?

=== source begin ===

procedure Test(a: array of String);
var
   s: String;
begin
   for s in a do
     Writeln(s);
end;
procedure Test2(a: array of Integer);
var
   i: Integer;
begin
   for i in a do
     Writeln(i);
end;
var
   s: String;
   i: Integer;
begin
   s := 'Hello World';
   Test(s);
   i := 42;
   Test2(i);
end.

=== source end ===

Calling "Test" with a constant string ("Test('Hello World');") or "Test2" with a constant integer ("Test2(42);") does not compile though...

Regards,
Sven

Sven Barth wrote

Related question, but the other way round. The following code does compile in FPC (didn't test Delphi). Is that by design?

[snip passing single element to open array parameter]

Yes. It also works in TP/Delphi.

Jonas

Ok, thanks. I just stumbled upon it some time ago by accident (like the TVarRec cast some more time ago ^^)

Regards,
Sven