Proposal: Extensible exceptions
Duncan Coutts
duncan.coutts at worc.ox.ac.uk
Fri Jul 18 12:04:14 EDT 2008
On Fri, 2008-07-18 at 11:19 -0400, Brandon S. Allbery KF8NH wrote:
> On 2008 Jul 18, at 11:05, Ian Lynagh wrote:
>
> > On Thu, Jul 17, 2008 at 09:16:36AM -0400, Isaac Dupree wrote:
> >>
> >> I'm not entirely happy with this particular sketch of a proposal,
> >> but do
> >> people think that my initial issue is something to be concerned
> >> about at
> >> all? (I'd be glad to be disproved :-)
> >
> > It's hard to say if it'll be a problem in practice - we don't have any
> > experience with writing exception hierarchies.
>
>
> I'm going to ask a possibly silly question: has anyone thought about
> this vis-a-vis Simon's proposal of a new signals API? It's not that
> unusual for signals (usually SIGUSR1/SIGUSR2, often SIGINT, SIGHUP,
> sometimes SIGABRT, SIGQUIT) to be used as asynchronous triggers ---
> which might be best represented in the "Haskell world" as special
> exceptions. Likewise, it often makes sense to treat SIGPIPE, SIGHUP,
> SIGINT as exceptions instead of signals.
SIGINT will be an exception in ghc-6.10. It will throw an async
exception to the main thread. We're just trying to think of the details
though, eg how to programs like ghci ignore ^C and can it be done in a
portable way.
SIGPIPE can be ignored because we get a sync exception when we write to
a pipe with no reader.
Duncan
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