Functor
From HaskellWiki
(Difference between revisions)
m |
m |
||
Line 1: | Line 1: | ||
− | {{Standard class|Functor|module=Control.Monad|module | + | {{Standard class|Functor|module=Control.Monad|module-doc=Control-Monad|package=base}} |
The '''Functor''' class is defined like this: | The '''Functor''' class is defined like this: | ||
Revision as of 03:20, 2 January 2006
import Control.Monad |
The Functor class is defined like this:
class Functor f where fmap :: (a -> b) -> f a -> f b
All instances of Functor should obey:
fmap id = id fmap (p . q) = (fmap p) . (fmap q)