Proposal: add Control.Monad.whenJust ∷ (Monad m) ⇒ Maybe α→(α→ m ()) → m ()
mikhail.vorozhtsov at gmail.com
Wed Nov 30 10:40:27 CET 2011
On 11/30/2011 02:11 PM, Liyang HU wrote:
> This particular pattern crops up a lot for me. Does it for anyone else?
> I (half-heartedly) propose adding to Control.Monad the following:
>> -- | A variation of 'when' for 'Maybe a'.
>> whenJust :: (Monad m) => Maybe a -> (a -> m ()) -> m ()
>> whenJust = flip (maybe (return ()))
We already have it. See Data.Foldable.forM_
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