[Haskell-cafe] Pointed, but not Applicative

Sebastian Fischer fischer at nii.ac.jp
Mon Aug 29 05:00:19 CEST 2011

On Sun, Aug 28, 2011 at 12:41 AM, Sönke Hahn <shahn at cs.tu-berlin.de> wrote:
> I was wondering which
> type could be an instance of Pointed, but not of Applicative. But I can't
> think of one. Any ideas?

Functional lists:

    type FList a = [a] -> [a]

they have a Monoid instance for empty and append, a "point" function
for singletons but Applicative or Monad cannot be defined without
converting back and forth to ordinary lists.


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