Re: [Haskell-cafe] ANNOUNCE: control-monad-failure and safe-failure

17 Nov 2009


      Excerpts from Kalman Noel's message of Tue Nov 17 07:47:14 +0100 2009:
...
Michael Snoyman schrieb:
...
control-monad-failure provides a basic notion of failure which does not
commit to any concrete representation.
It is just a version of the MonadError class without the annoying bits.
...
class MonadFailure e m where failure :: e -> m a
Why is it called "MonadFailure" (specifically, what's the "Monad" bit doing 
there)?
Because of 'Monad m' being a superclass of 'MonadFailure e m'.

Here is the class:
class Monad m => MonadFailure e m where
  failure :: e -> m a

-- 
Nicolas Pouillard
http://nicolaspouillard.fr