18 Jan
2009
18 Jan
'09
12:49 p.m.
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