Adding an ignore function to Control.Monad
malcolm.wallace at cs.york.ac.uk
Mon Dec 14 11:43:54 EST 2009
>> ## Control.Monad.void m a -> m ()
>> (or void :: f a -> f ())
By the latter, I take it you mean
void :: Functor f => f a -> f ()
void = fmap (const ())
thereby avoiding any premature restriction to Monad. I would be in
favour of the generalisation (and of the name 'void').
>> ## Control.Monad.discard :: f a -> f ()
I vote against 'discard', mainly because I already use it frequently,
as an infix operator
discard :: Applicative f => f a -> f b -> f a
It can be jolly useful to intersperse with the `apply` operator e.g.
list item = empty
fmap (:) `apply` item
`discard` satisfy ":"
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