Re: Handling invalid objects

[Simon Wright <simon@pushface.org>]

Justin Gombos <rpbkbq.xax.gld@uluv.kbq> writes:

> Exception raising and handling is often viewed as writing code that
> will never execute.  Predefined exceptions must be handled when
> there is an expectation they will be raised, but their usefullness
> stops there.  Beyond that, it's like writing erroneous code on
> purpose.

Code that _should_ never execute, perhaps!

Exceptions are for things that can't be handled locally because of
lack of application knowledge. For example, how to handle a
Socket_Error?

And also, I think, for contract violation, where the contract can;t be
enforced in the language. Now we can say 'not null access' but in
Ada95 we can't.

>> There are cases where exceptions are outlawed; most of them are not
>> justified.  Even if they were all justified, advocating a return to
>> the mess that error codes create is not a viable option.
>
> It's a mess regardless.  Clearly Ada is deficient in this respect,
> as all languages seem to be.

I think it's called living in the real world.