
6 May
2009
6 May
'09
5:59 p.m.
On Tue, May 05, 2009 at 03:07:16PM -0300, Marco TĂșlio Gontijo e Silva wrote:
and then your automatic lifting instance would be something like
instance (F f, M f2 a) => M (f :.: f2) a
where :.: denotes functor composition.
Ok, I think this is another possibility. But how could I define :.:?
newtype (g :.: f) a = O { unO :: g (f a) } Something like this is already defined in both the TypeCompose and category-extras libraries. -Brent