On Mon, Jun 29, 2009 at 01:45:45PM +0100, Ross Paterson wrote:
The proposal is that the following functions
(<$) :: Functor f => a -> f b -> f a (*>) :: Applicative f => f a -> f b -> f b (<*) :: Applicative f => f a -> f b -> f a some :: Alternative f => f a -> f [a] many :: Alternative f => f a -> f [a]
are moved into the corresponding classes, with the existing implementations as default definitions.
Henning asked for concrete examples (i.e. code) where this would give a substantial performance win while still defining the same function, including termination properties. (But it seems reasonable not to rely on RULES to improve the asymptotic complexity.) I gave an example for (<$). Does anyone have concrete examples for the others?