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

Kalman Noel noel.kalman at googlemail.com
Tue Nov 17 06:55:54 EST 2009


Nicolas Pouillard schrieb:
>>>> 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

Oh ok; I misguidedly took the line at the top to be the class definition. I'd 
still be interested if such a simple Failure class could be meaningful or 
useful for mere, say, Applicatives.



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