18 Feb
2016
18 Feb
'16
1:03 a.m.
On Thu, Feb 18, 2016 at 1:57 PM, martin
The only need for the functor requirement is in the default definition of mapMaybe - so why not drop it?
Since fmap can be defined in terms of mapMaybe: fmap f = mapMaybe (Just . f) Filtrable should imply Functor in the same way that Traversable implies Foldable. -- Chris Wong (https://lambda.xyz) "I had not the vaguest idea what this meant and when I could not remember the words, my tutor threw the book at my head, which did not stimulate my intellect in any way." -- Bertrand Russell