Re: [Gm2] VAR array parameter type compatibility

[Fischlin Andreas]

Hi all,

I agree, this compatibility should actually work and the compiler  
should accept types which have been made equal. Other examples are:

TYPE
        MYSHORTREAL = REAL;

TYPE
        PROCA = PROCEDURE (VAR ARRAY OF REAL);
        PROCB = PROCEDURE (VAR ARRAY OF MYSHORTREAL);

VAR
        pa: PROCA; pb: PROCB;
        x: ARRAY [0..1] OF REAL;
        y: ARRAY [0..1] OF MYSHORTREAL;

PROCEDURE ProcA(VAR z: ARRAY OF REAL);
PROCEDURE ProcB(VAR z: ARRAY OF MYSHORTREAL);

then pa and pb should be type compatible and interchangeably usable,  
i.e. all following statements should all be legal:

        x := y;
        pa := ProcA; pb := ProcB;
        pa(x); pa(y); pb(x); pb(y);
        pa := ProcB; pb := ProcA;
        pa(x); pa(y); pb(x); pb(y);

        
Regards,
Andreas
                


On 01/Feb/2010, at 22:07 , SiTex Graphics wrote:

> Hi Gaius,
>
> I have a case where GM2 appears to enforce different type
> compatibility rules depending on whether a VAR array parameter is a
> variable or the parameter in a procedure.
>
> With
>
> TYPE
>  fooADDRESS = ADDRESS;
>
> VAR
>  foo : ARRAY [0..9] OF fooADDRESS;
>
> GM2 accepts a call to
>
> PROCEDURE DoAddress(VAR a : ARRAY OF ADDRESS)
>
> passing foo.  However, the following call produces a compiler error:
>
> PROCEDURE DoFoo(VAR f : ARRAY OF fooADDRESS);
> BEGIN
>  DoAddress(f);
> END DoFoo;
>
> "'f' cannot be passed to a VAR formal parameter"
>
> Test code attached.  Compile with
>
> gm2 -fiso -c arraytype.mod
>
> -Scott
> <arraytype.mod>_______________________________________________
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