[fpc-pascal]Where is the error?

[Michalis Kamburelis]

When you compile using -S2 parameter you are compiling in objfpc mode. 
This mode is not exactly compatible with Delphi. In this particular 
case, the problem is that in objfpc mode method parameters can't have 
the same name as the object properties and fields (that's what 
"Duplicate identifier ..." errors mean). That's often very nice 
safety-check, however it makes many Delphi code invalid in objfpc mode.

Solution is to compile in delphi mode:
   fpc -Mdelphi mat.pas
works OK.

Alan Mead wrote:
> I am trying to compile a Delphi matrix package using fpc 1.9.4 and I
> don't know if I misunderstand FPC's overloading or if there is an FPC
> problem. The code is located here:
> 
> http://www.fssc.demon.co.uk/Delphi/delphi.htm#TMatrix
> 
> Lines 84-85 define a transpose method:
> 
> 84     function  transpose : TMatrix; {overload;}
> 85     function  transpose (m : TMatrix) : TMatrix; {overload;}
> 
> (I commented out the overload keyword.. doesn't seem to matter.).  I
> don't see any forward declaration of 'transpose':
> 
> [amead at alan misc code]$ grep -i transpose mat.pas
>                    function  transpose : TMatrix; overload;
>                    function  transpose (m : TMatrix) : TMatrix;
> overload;
> { Transpose matrix 'Self', Self is thus destroyed and replaced       
>  }
> { Usage:  A.transpose                                                
>  }
> function TMatrix.Transpose : TMatrix;
>     { move data from transpose to Self }
> { Transpose the matrix 'm' into Self                                 
>  }
> { Usage:  T.transpose (A);   Tranposes A and puts result into T      
> }
> { Will also accept T.transpose (T)                                   
> }
> function TMatrix.Transpose (m : TMatrix) : TMatrix;
>      raise EMatrixSizeError.Create ('Destination matrix has incorrect
> dimensions for transpose');
>   { If the user is trying to transpose itself.... }
>     tmp.Transpose (st);
>     Self.Transpose (ns);
> 
> This is the output when I try to compile:
> 
> [amead at alan misc code]$ fpc -gl -S2 -Cr -Co mat.pas
> Free Pascal Compiler version 1.9.4 [2004/05/30] for i386
> Copyright (c) 1993-2004 by Florian Klaempfl
> Target OS: Linux for i386
> Compiling mat.pas
> mat.pas(85,41) Error: Duplicate identifier "M"
> mat.pas(85,30) Error: Function is already declared Public/Forward
> "TMatrix.transpose:TMatrix"
> mat.pas(87,38) Error: Duplicate identifier "M"
> mat.pas(89,38) Error: Duplicate identifier "M"
> mat.pas(90,38) Error: Duplicate identifier "M"
> mat.pas(91,30) Error: Function is already declared Public/Forward
> "TMatrix.mult(Extended):TMatrix"
> mat.pas(93,38) Error: Duplicate identifier "M"
> mat.pas(103,40) Error: Duplicate identifier "M"
> mat.pas(117,73) Error: Duplicate identifier "c"
> mat.pas(118,48) Error: Duplicate identifier "r"
> mat.pas(118,73) Error: Duplicate identifier "c"
> mat.pas(119,59) Error: Duplicate identifier "r"
> mat.pas(127,1) Fatal: There were 12 errors compiling module, stopping
> 
> Any ideas on getting fpc to compile this?  I'm confused by the
> reference to 'm'? 
> 
> -Alan
> 
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