[Solved] How to overload Implicit / Explicit ?

[v.denis]

Hi,

How to overload Implicit / Explicit operators in FPC?

Thanks.

[Leledumbo]

Try the same way as Delphi with {$mode delphi}? I don't know the current state, just try with latest trunk.

[v.denis]

such example

Code: [Select]

program ovl_delphi;

{$ifdef fpc}
{$mode delphi}
{$endif}


type
  TMyClass = record
    FName: string;
    constructor Create(const AName: string);
    class operator Implicit(const AValue: string): TMyClass;
  end;

  { TMyClass }

constructor TMyClass.Create(const AName: string);
begin
  FName := AName;
end;

class operator TMyClass.Implicit(const AValue: string): TMyClass;
begin
  Result := TMyClass.Create(AValue);
end;

var
  c: TMyClass;

begin
  c := 'hello';

end.
works fine both in FPC and Delphi,

but I need to implicitly create class (actually interface), not record. Delphi can't do that (well it can I guess in XE4 compiler based on LLVM)

[v.denis]

Solved.

It's even simpler than Delphi.

here's the declaration example

Code: [Select]

operator :=(const AValue: string): IMyIntf;
begin
  Result := TMyClass.Create(AValue);
end;
it can be used both as assignment to variable and as function argument