Re: [fpc-pascal] How to use a static method as procedure variable?

2015-07-11 Thread silvioprog 
On Sun, Jul 5, 2015 at 2:41 PM, Ewald ew...@yellowcouch.org wrote:


 On 30 Jun 2015, at 20:54, silvioprog wrote:


 The code above compiles fine in Delphi (tested in XE 7), but in FPC I got
 the following compiling error:

 Unit1.pas(46,14) Error: Incompatible types: got class method type of
 procedure({Open} Array Of Byte;out AnsiString) of object;Register
 expected procedure variable type of procedure({Open} Array Of Byte;out
 AnsiString);Register.

 Is this a bug or I need to enable some switch?


 Back in 2012 I had a similar issue. Original message can be found here:
 http://lists.freepascal.org/pipermail/fpc-pascal/2012-December/035921.html

 I fixed it by declaring a type that includes the hidden parameter
 mentioned in that thread, so in your case:

 Type
 TMyProc = procedure(aClassType: TClass; ABytes: array of Byte; out
 AOutput: AnsiString);

 the invocation then becomes
 FMyProc(ClassType, [65, 66, 67], S);

 instead of
 FMyProc([65, 66, 67], S);

 And, of course, the assignment to FMyProc becomes more verbose and less
 type-safe:
 FMyProc := TMyProc(Pointer(@DoMyProc));

 NOTE: This is a hack. It is not documented anywhere, but i have used this
 approach since late 2012 without any problems so far. Better be careful and
 write a small sanity test that checks correct operation every time you use
 a new compiler.


Very nice, I'll try that, thank you! =)

-- 
Silvio Clécio
My public projects - github.com/silvioprog
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Re: [fpc-pascal] How to use a static method as procedure variable?

2015-07-05 Thread Ewald 

On 30 Jun 2015, at 20:54, silvioprog wrote:

 
 The code above compiles fine in Delphi (tested in XE 7), but in FPC I got the 
 following compiling error:
 
 Unit1.pas(46,14) Error: Incompatible types: got class method type of 
 procedure({Open} Array Of Byte;out AnsiString) of object;Register expected 
 procedure variable type of procedure({Open} Array Of Byte;out 
 AnsiString);Register.
 
 Is this a bug or I need to enable some switch?
 

Back in 2012 I had a similar issue. Original message can be found here: 
http://lists.freepascal.org/pipermail/fpc-pascal/2012-December/035921.html

I fixed it by declaring a type that includes the hidden parameter mentioned in 
that thread, so in your case:

Type
TMyProc = procedure(aClassType: TClass; ABytes: array of Byte; 
out AOutput: AnsiString);

the invocation then becomes
FMyProc(ClassType, [65, 66, 67], S);

instead of 
FMyProc([65, 66, 67], S);

And, of course, the assignment to FMyProc becomes more verbose and less 
type-safe: 
FMyProc := TMyProc(Pointer(@DoMyProc));

NOTE: This is a hack. It is not documented anywhere, but i have used this 
approach since late 2012 without any problems so far. Better be careful and 
write a small sanity test that checks correct operation every time you use a 
new compiler.


--
Ewald

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Re: [fpc-pascal] How to use a static method as procedure variable?

2015-06-30 Thread Jonas Maebe 
On 30/06/15 20:54, silvioprog wrote:
 The code above compiles fine in Delphi (tested in XE 7), but in FPC I
 got the following compiling error:
 
 Unit1.pas(46,14) Error: Incompatible types: got class method type of
 procedure({Open} Array Of Byte;out AnsiString) of object;Register
 expected procedure variable type of procedure({Open} Array Of Byte;out
 AnsiString);Register.
 
 Is this a bug or I need to enable some switch?

FPC currently only supports that in Delphi mode:
http://bugs.freepascal.org/view.php?id=27414


Jonas
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Re: [fpc-pascal] How to use a static method as procedure variable?

2015-06-30 Thread silvioprog 
On Tue, Jun 30, 2015 at 4:22 PM, Jonas Maebe jonas.ma...@elis.ugent.be
wrote:

 On 30/06/15 20:54, silvioprog wrote:
  The code above compiles fine in Delphi (tested in XE 7), but in FPC I
  got the following compiling error:
 
  Unit1.pas(46,14) Error: Incompatible types: got class method type of
  procedure({Open} Array Of Byte;out AnsiString) of object;Register
  expected procedure variable type of procedure({Open} Array Of Byte;out
  AnsiString);Register.
 
  Is this a bug or I need to enable some switch?

 FPC currently only supports that in Delphi mode:
 http://bugs.freepascal.org/view.php?id=27414

 Jonas


Hm... my unit (+- 500 lines) is implemented in mode objfpc, so if I change
it to mode delphi I'll get several sintax erros.

It seems that the only way to fix that is using an usual procedure instead
of a static method. =/

Plans to fix it for mode objfpc or it won't be solved?

Thanks!

-- 
Silvio Clécio
My public projects - github.com/silvioprog
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[fpc-pascal] How to use a static method as procedure variable?

2015-06-30 Thread silvioprog 
Hello,

Consider the following sample:

=== begin code ===

type
  TMyProc = procedure(ABytes: array of Byte; out AOutput: AnsiString);

  TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
  private class var
FMyProc: TMyProc;
  public
class constructor Create;
class procedure DoMyProc(ABytes: array of Byte; out AOutput:
AnsiString); overload; static;
class property MyProc: TMyProc read FMyProc write FMyProc;
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  S: AnsiString;
begin
  MyProc([65, 66, 67], S);
  ShowMessage(string(S));
end;

class constructor TForm1.Create;
begin
  FMyProc := @DoMyProc;
end;

class procedure TForm1.DoMyProc(ABytes: array of Byte; out AOutput:
AnsiString);
begin
  SetLength(AOutput, Length(ABytes));
  Move(ABytes[0], AOutput[1], Length(ABytes));
end;

=== end code ===

The code above compiles fine in Delphi (tested in XE 7), but in FPC I got
the following compiling error:

Unit1.pas(46,14) Error: Incompatible types: got class method type of
procedure({Open} Array Of Byte;out AnsiString) of object;Register
expected procedure variable type of procedure({Open} Array Of Byte;out
AnsiString);Register.

Is this a bug or I need to enable some switch?

Thank you!

-- 
Silvio Clécio
My public projects - github.com/silvioprog
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