[Haskell-cafe] Why the reluctance to introduce the Functor requirement on Monad?

Ivan Lazar Miljenovic ivan.miljenovic at gmail.com
Sun Jul 24 00:19:11 CEST 2011


On 24 July 2011 00:49, Sebastien Zany <sebastien at chaoticresearch.com> wrote:
> Would it be theoretically possible/convenient to be able to put boilerplate
> like this in class definitions?

Not really: what happens for Functors that aren't Monads?  Also, for
some Monads there may be a more efficient definition of fmap than
using liftM, so even an automatic reverse instance wouldn't always be
wanted.

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com



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