24 May
2013
24 May
'13
10:36 p.m.
On the other hand with classes like Apply or Bind you get access to lots of useful semigroup-like structures you can still reason about in general, not in particular, including things that can't be made Applicative/Monadic. (e.g. IntMap).
One example is that Bind would occasionally be handy for EDSLs that don't permit lifting arbitrary values as a no-op. Incidentally, desugaring do notation does not actually use return at all, if memory serves me...
This strikes me as a very good reason for pointed. Similar to how I'd like to see GArr included in ghc. +1