El vie, 23-07-2010 a las 16:35 -0700, michael rice escribió:
> Thanks all,
>
> Wild, at least up to the "optional" part, which I haven't dug into
> yet.
>
> So the (+) for the Maybe monad and the (+) for the List monad are one
> in the same, the magic springs from the monads.
>
> Why is it called "lift"-ing?
g :: m a -> m b -> m c
/\
/||\
||
||
f :: a -> b -> c
liftM2 "lifts" the function f and transforms it into the function g =
liftM2 f.
Does that picture help?
Jürgen
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