Re: darcs patch: Add justIf to Data.Maybe

Joachim Breitner writes:

Hi,

I propose the attached change, with a discussion timeframe until end of September. The corresponding ticket is http://hackage.haskell.org/trac/ghc/ticket/3446

Thanks, Joachim

I have been meaning to get round to proposing check for Data.Monad:

check :: (MonadPlus m) => (a -> Bool) -> a -> m a check p a | p a = return a | otherwise = mzero

Now justIf = flip (check . const) So I suggest that it would be better to add check first(, and then possibly switch the order of arguments to justIf). -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk