On Sun, 2009-01-18 at 11:23 +0000, Andrew Coppin wrote: > Jonathan Cast wrote: > > On Sat, 2009-01-17 at 12:04 +0000, Andrew Coppin wrote: > > > >> > >>> instance (Monad m) => Functor m where > >>> fmap f ma = do a <- ma; return (f a) > >>> > >>> > >> While that's quite interesting from a mathematical point of view, how is > >> this "useful" for programming purposes? > >> > > > > Good Lord. fmap (as above) is *at least* useful enough to be in the > > standard library! (Control.Monad.liftM). > > Given that liftM exists, why is having an identical implementation for > fmap useful?
What? jcc _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe