Re: [PATCH 3/9] pkl: disallow immediate break/continue/return in EXCOND

[Mohammad-Reza Nabipoor]

Hi Jose.


On Thu, Dec 28, 2023 at 03:16:30PM +0100, Jose E. Marchesi wrote:
> 
> > This commit disallow change in control flow from EXCOND expressions
> > which the LHS of the operator is a compound statement.
> >
> > The following Poke snippets are now illegal:
> >
> > Sample 1:
> >
> >   whlie (condition)
> >     { break; } ?! E_elem;
> >
> > Sample 2:
> >
> >   whlie (condition)
> >     { continue; } ?! E_elem;
> >
> > Sample 3:
> >
> >   fun f = int:
> >     {
> >       { return 1; } ?! E_elem;
> >       return 0;
> >     }
> 
> Hmmm, I assume the above currently breaks the compiler and that is what
> motivates this patch?
> 
> I don't see anything wrong in the code above: all of these ought to
> work.  Do you have any particular reason why to forbid having break,
> continue and return statements in EXCOND?
> 

Besides breaking the compiler, I think,

1. Expressions that can change the flow of programs don't seem to be correct to 
me.
   The purpose of EXCOND is to verify that a block of code doesn't raise an
   exception.
2. It complicates the codegen for my E_constriant location tracking patch.



Regards,
Mohammad-Reza