maybeRead in base

Edward Kmett ekmett at gmail.com
Thu Aug 16 17:14:05 CEST 2012


This is part of why I'm not a fan of (.:) in the first place, but trying to generalize through Category doesn't offer anything here.

Sent from my iPad

On Aug 16, 2012, at 7:16 AM, Twan van Laarhoven <twanvl at gmail.com> wrote:

> On 15/08/12 19:02, Edward Kmett wrote:
>> I'm not a huge fan of (.:), but you insist on adding it, please generalize it to
>> fmap.fmap.
>> 
>> (.:) :: (Functor f, Functor g) => (a -> b) -> f (g a) -> f (g b)
>> 
>> This subsumes the other use case.
> 
> For the love of Categories, please don't go down this road. fmap is not the proper generalization of (.).
> 
> 
> Twan
> 
> 
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