Re: Exceptions

[Adam Beneschan <adam@irvine.com>]

On Dec 7, 10:59 am, Simon Wright <simon.j.wri...@mac.com> wrote:
> Adam Beneschan <a...@irvine.com> writes:
> > On Dec 6, 7:00 am, shaunpatter...@gmail.com wrote:
> >> Is there any way to force programmers to catch exception that
> >> your function throws?
>
> > Not in Ada.  If you're looking for, say, a pragma that you can put
> > on a subprogram declaration to tell the compiler to reject any code
> > that calls the subprogram in a place not governed by an exception
> > handler for a specified exception---that's an interesting idea, and
> > maybe if there's enough interest it could be added to a future
> > revision of Ada, probably Annex H.  I don't see any problem with a
> > particular compiler vendor implementing a pragma like that, though,
> > although of course it would be non-portable; perhaps you could ask
> > your vendor if they'd be willing to implement something like that.
> > It would probably not be too difficult to implement.
>
> I think this would be a very bad idea. I don't want to be forced to
> deal with the exception 'here' when it would be better handled by my
> caller.

I wouldn't want that either.  But this seems like a "coding standard"
sort of thing that organizations sometimes impose to force their less-
experienced programmers to be more careful.  I know I'd grumble if I
had to adhere to a standard like that, but some organizations seem to
think it's a good thing anyway.  I can see how a pragma like this
could be useful in that sort of context.

Hopefully the OP is talking about writing a function for internal use
by other programmers in the same organization, not one that would be
part of a library to be released to the public or for use by
customers.  If it's either of the last two, then it's definitely a bad
idea---it shouldn't be any of his business how other outside users
deal with exceptions.  Unless, of course, the exception isn't really
an exceptional condition but rather a "normal result" returned in a
different way, which I think is a really, really bad idea.

                              -- Adam