Transformation Monoid

[matthewleon]

Is it worth including something like newtype Transformation = Transformation (t -> t) with a Monoid over composition and mempty = id?

[garyb]

See Endo: https://github.com/purescript/purescript-monoid/blob/master/src/Data/Monoid/Endo.purs 😄

[matthewleon]

Oh dear. Time to seriously up my (nonexistent) category theory game. Thanks.

[garyb]

If you're looking for the type you're half way there!