Proposal: Add a strict version of <$> for monads

Twan van Laarhoven twanvl at
Fri Nov 29 14:50:26 UTC 2013

On 29/11/13 12:23, Johan Tibell wrote:
> On Fri, Nov 29, 2013 at 1:19 PM, Twan van Laarhoven <twanvl at
> <mailto:twanvl at>> wrote:
>     I don't like that this function is implemented for Monads, I think that it
>     makes sense for some other functors as well. Though to do this 'properly' we
>     would probably end up with another typeclass "StrictFunctor" or something,
>     and that is perhaps too much unnecessary complexity.
> Do you have an example of such a functor?
> -- Johan

The first thing that came to mind was ZipList. Perhaps a more realistic example 
would be parsing combinator or FRP libraries that are applicative but not monadic.


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