liftM package:rebase

Promote a function to a monad.
Promote a function to a monad, scanning the monadic arguments from left to right. For example,
liftM2 (+) [0,1] [0,2] = [0,2,1,3]
liftM2 (+) (Just 1) Nothing = Nothing
Promote a function to a monad, scanning the monadic arguments from left to right (cf. liftM2).
Promote a function to a monad, scanning the monadic arguments from left to right (cf. liftM2).
Promote a function to a monad, scanning the monadic arguments from left to right (cf. liftM2).