Re: contracted exceptions

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Ray Blaak <rAYblaaK@STRIPCAPStelus.net> writes:

> Robert A Duff <bobduff@shell01.TheWorld.com> writes:
>> Ray Blaak <rAYblaaK@STRIPCAPStelus.net> writes:
>> > or even worse:
>> >
>> >   try
>> >   {
>> >     doSomething();
>> >   }
>> >   catch (SomeError e)
>> >   {
>> >   }
>> 
>> Well, this part of the problem can't be blamed on the language.
>> This code is just plain bad practise.  The solution is better
>> training for programmers, not better language design
>
> Well, you are right in theory. The problem is that such naive programmers are
> directed by the compiler to do something about the exception, and being naive
> they make this mistake. Training is hard, and this particular problem is
> unexpectedly pervasive.

I agree that training is hard, but this particular case seems pretty
obvious.  One can have a coding convention, and enforce it by code
reviews.  The compiler could warn about the above evil.  The language
could define such a warning to be required.  As in all cases of a
warning that is sometimes wrong, you need a way to suppress the message
locally.

Really, if a programmer doesn't understand why the above code is bad
practise, the only imaginable solution is better training -- whether or
not the language has Java-like rules that might encourage such bad
practise.  As I said, I've seen this bad practise in Ada, too -- some
programmer was getting a Constraint_Error at run time, didn't understand
why, and decided to put a penny in the fusebox.

- Bob