[Haskell-cafe] Re: Cleaning up threads

[Bas van Dijk]

On Wed, Sep 22, 2010 at 3:18 AM, Mitar <mmitar at gmail.com> wrote:
> What would I also like to see in Haskell is that it would be somehow
> possible to see which all exceptions could your function (through used
> functions there) throw. In this way it would be really possible to
> make async-exception-safe functions (as we really do not want
> catch-all all around). (Of course the problem with this approach is if
> somebody changes underlying function it could get additional possible
> exception(s) to be thrown.)
>
> So it would be even better if this would be solved like pattern
> matching warning (so you could see if you are missing some exception
> through warning) or even better: that type system would enforce you to
> or catch or declare throwing/passing exception yourself. Similar how
> Java has.
>
> Because one other major Haskell's selling point is that you (are said
> to) know from type if and which side-effects a function has. This is
> the story behind IO monad. And with exceptions you do not have this
> information anymore. I believe this should be visible through type
> system.
>
> Something like:
>
> http://paczesiowa.blogspot.com/2010/01/pure-extensible-exceptions-and-self.html

For type-safe _synchronous_ exception handling we have Pepe Iborra's:

http://hackage.haskell.org/package/control-monad-exception

However we don't have anything similar for asynchronous exception handling.

What will a type-safe asynchronous exception handling API look like?
What guarantees should it provide?

Regards,

Bas