[Haskell] A collection of related proposals regarding monads

[Cale Gibbard]

On 05/01/06, Taral <taralx at gmail.com> wrote:
> On 1/5/06, Cale Gibbard <cgibbard at gmail.com> wrote:
> > class Applicative m => Monad m where
> >     m >>= f = join (map f m)
> >
> >     instance PointedFunctor m where
> >         require return
> >         map f x = x >>= (return . f)
>
> Um, it looks like map and (>>=) are recursive...
>

The intent is that this is similar to other default method
declarations which aren't really recursive, though they may look like
it.

>From the Ord class in the Prelude, we have:

    compare x y
         | x == y    =  EQ
         | x <= y    =  LT
         | otherwise =  GT

    x <= y           =  compare x y /= GT
    ....

Which looks recursive, but it's not, because the user is required to
provide one of the two.
 - Cale