[Haskell-cafe] Taking Exception to Exceptions

[Cristiano Paris]

On Thu, Jan 8, 2009 at 12:32 AM, Austin Seipp <mad.one at gmail.com> wrote:
> Excerpts from Immanuel Litzroth's message of Wed Jan 07 16:53:30 -0600 2009:
> ...
>> I am little amazed that I cannot get catch, try or mapException to work
>> without telling them which exceptions I want to catch.
>> What is the rationale behind this?
>
> The rational is that it's normally not a good idea to simply gobble
> all exceptions; although the library makes it possible to do this
> anyway.

I'd advice always putting an additional generic catch-all at the top
level, at least to present the user a (possibly generic) error
message, just to stay in control.

This avoids the possibility of having an unwanted/unknown behavior
from the run-time stack (for example, having the web server returning
a generic 500 Internal Server error report, filled with every sort of
goods a cracker would be happy for).

Cristiano