4 Nov 11:47
Re: Control.Exception
Simon Marlow <marlowsd <at> gmail.com>
2008-11-04 10:47:13 GMT
2008-11-04 10:47:13 GMT
Jason Dagit wrote: > On Mon, Nov 3, 2008 at 6:24 AM, Simon Marlow <marlowsd <at> gmail.com> wrote: >> Jason Dagit wrote: >>> On Wed, Oct 8, 2008 at 1:19 AM, Simon Marlow <marlowsd <at> gmail.com> wrote: >>>> Johannes Waldmann wrote: >>>>> with 6.10, the following does not typecheck: >>>>> >>>>> foo `Control.Exception.catch` \ _ -> return bar >>>>> >>>>> Ambiguous type variable `e' in the constraint: >>>>> `Control.Exception.Exception e' >>>>> >>>>> It is probably bad programming style anyway but what is the workaround? >>>> As long as you're aware that it is bad programming style. We >>>> deliberately >>>> didn't include an easy way to do this, because we want people to think >>>> about >>>> why they need to catch *all* exceptions (most of the time it's a bug). >>> Since the above is bad form, what should I be doing? Could someone >>> please provide some examples or point me at the list of exceptions >>> that I can catch? What about catching multiple types of exceptions? >> Let's distinguish two kinds of exception handling: > > Thanks. This helps a lot. Mind if I put it somewhere, such as on the wiki? A good description of how to deal with exceptions would be great to have in the Haddock documentation for Control.Exception - would you (or someone else) like to write and submit a patch? Or failing that, just putting it on the wiki would be useful too. Cheers, Simon
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