Functor => Applicative => Monad

[Stephen Tetley]

Me thinks there's more value that "the next language after Haskell"
might have such a hierarchy than Haskell itself.

At Haskell 1.3 I think there was one text book (Davie), possibly none
at Haskell 1.4 and many at Haskell 98. The value of invalidating 12 or
so years of documentation for "logic" seems somewhat questionable from
my perspective. If either proposal were limited to just adding class
constraints to get the desired hierarchy rather than eliminating
methods, they might have more legs...