Re: [Gm2] Bug report.... offending code works outside of procedure, but inside - not.

[Dragiša Durić]

Andreas, 

Simple deletion of procedure and putting of offending code into main
body produces no error.
...
TYPE
  Where = PROCEDURE (): BOOLEAN;

  VAR
    where: Where;
  BEGIN
    where := AlwaysTrue;

END TestCase.

After deleting procedure, it compiles without error. So - bug probably
IS related to scope handling somehow.

Anyway, it's just a guess, Test case is there, so developers can find
what and where it really is.


On Wed, 2010-07-28 at 12:41 +0000, Fischlin Andreas wrote: 
> It seems the compiler is not recognizing the difference between procedure 
> variable assignment and the case where an expression is to be evaluated. The 
> difference in the syntax should be:
> 
>       where := AlwaysTrue;
> 
> and
> 
>       where := AlwaysTrue();
> 
> The latter should lead to an error "incompatible types" and the first should 
> be accepted as an assignement statement. Modula-2 syntax is clear on this, 
> since a procedure of standard type PROC can not be confounded with an 
> expression. Only function procedures can be a factor or term in an expression 
> and need therefore be called by using parantheses when actually called. 
> 
> Duric, you say something about an outer scope, but scope should not matter in 
> any way (except of course that the assignment statement has to be within the 
> scope of 'where' as well as 'AlwaysTrue').
> 
> Regards,
> Andreas
>  
> 
> ETH Zurich
> Prof. Dr. Andreas Fischlin
> Systems Ecology - Institute of Integrative Biology
> CHN E 21.1
> Universitaetstrasse 16
> 8092 Zurich
> SWITZERLAND
> 
> address@hidden
> www.sysecol.ethz.ch
> 
> +41 44 633-6090 phone
> +41 44 633-1136 fax
> +41 79 221-4657 mobile
> 
>              Make it as simple as possible, but distrust it!
> ________________________________________________________________________
> 
> 
> 
> On 25/Jul/2010, at 07:36 , Dragiša Durić wrote:
> 
> > gm2 -fiso -c TestCase.mod
> > TestCase.mod:15:5: error: assignment designator 'where' of type 'Where'
> > is a variable and expression 'AlwaysTrue' of type 'BOOLEAN' are
> > incompatible
> > 
> > ==================
> > MODULE TestCase;
> > 
> > PROCEDURE AlwaysTrue(): BOOLEAN;
> >  BEGIN
> >    RETURN TRUE;
> >  END AlwaysTrue;
> > 
> > TYPE
> >  Where = PROCEDURE (): BOOLEAN;
> > 
> > PROCEDURE DoIt();
> >  VAR
> >    where: Where;
> >  BEGIN
> >    where := AlwaysTrue;
> >  END DoIt;
> > 
> > END TestCase.
> > 
> > -- 
> > Dragiša Durić <address@hidden>
> > 
> > 
> > _______________________________________________
> > gm2 mailing list
> > address@hidden
> > http://lists.nongnu.org/mailman/listinfo/gm2
> 

-- 
Dragiša Durić <address@hidden>