Re: In case statment? (was Re: is exception when others => null;smart?)

["Marin David Condic" <mcondic.auntie.spam@acm.org>]

True enough, but I don't think that really changes anything with respect to
needing to look at your situation and see if it makes sense. A case
statement might process *some* of the set of possible values & adding new
enumerals can go to the default case. If it processes all of them and, while
designing it, you think about what action you want it to take if anything
new is added, you might have a proper accommodation.

I would generally agree that if a case statement is intended to process all
of a set of enumerals, avoiding "when others" helps you discover if you have
a problem should the set expand. Its just that "never" is a very long time
and engineers are wise to consider the unique circumstances around what they
are building and use what works best for that situation. A blanket rule of
"Never use 'when others'..." is a bad idea because sometimes it will make
sense to do so. That's why I dislike blanket coding conventions.

MDC
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Marin David Condic
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Robert Spooner <rls19@psu.edu> wrote in message
news:3DC04270.3060505@psu.edu...
> If you avoid using "when others" and a value is added to the enumeration
> type later, the compiler will tell you where _all_ the case statements
> using that enumeration type are so that you can examine them and see
> what changes should be made.  Then you don't have to spend a lot of time
> using the debugger to crawl around in your code finding and fixing the
> parts that don't work right.  There's no guarantee that the default case
> will be correct for a new value, and shifting errors from run time to
> compile time is one of Ada's bigest advantages in my estimation.
>
> Bob
>