Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
Bifunctors.
Bifunctors are "two-argument functors".
This module is the type-level equivalent of Data.Bifunctor.
Documentation
data Bimap :: (a -> Exp a') -> (b -> Exp b') -> f a b -> Exp (f a' b') Source #
Type-level bimap
.
Example
>>>
data Example where Ex :: a -> Example -- Hide the type of examples to avoid brittleness in different GHC versions
>>>
:kind! Ex (Eval (Bimap ((+) 1) (Flip (-) 1) '(2, 4)) :: (Natural, Natural))
Ex (Eval (Bimap ((+) 1) (Flip (-) 1) '(2, 4)) :: (Natural, Natural)) :: Example = Ex '(3, 3)
data First :: (a -> Exp b) -> f a c -> Exp (f b c) Source #
Type-level first
.
Apply a function along the first parameter of a bifunctor.
Example
>>>
:kind! Eval (First ((+) 1) '(3,"a"))
Eval (First ((+) 1) '(3,"a")) :: (Natural, Symbol) = '(4, "a")