Proposal: Add missing Foldable/Traversable instances for Prelude types

Bas van Dijk v.dijk.bas at
Sat Jan 22 17:12:00 CET 2011


On 22 January 2011 05:16, Edward Kmett <ekmett at> wrote:
> I went with the default being to avoid prematurely forcing a bottom when
> possible, to avoid being called out by the strictness police, but I'm not
> terribly wedded to the behavior.

Just for reference, the Functor instance on pairs is strict in the pair:

instance Functor ((,) a) where
        fmap f (x,y) = (x, f y)


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