Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
Documentation
inverseMap :: forall a k. (Bounded a, Enum a, Ord k) => (a -> k) -> k -> Maybe a Source #
Creates a function that is the inverse of a given function f
.
>>>
data Color = Red | Green | Blue deriving (Show, Enum, Bounded)
>>>
parse = inverseMap show :: String -> Maybe Color
>>>
parse "Red"
Just Red>>>
parse "Black"
Nothing