Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell98 |
Default lenses for simple total getters and total possibly polymorphic, updates. Useful for creating accessor labels for single constructor datatypes. Also useful field labels that are shared between all the constructors of a multi constructor datatypes.
- type (:->) f o = Lens Total f o
- type Total = (->)
- lens :: (f -> o) -> ((o -> i) -> f -> g) -> (f -> g) :-> (o -> i)
- get :: ((f -> g) :-> (o -> i)) -> f -> o
- modify :: ((f -> g) :-> (o -> i)) -> (o -> i) -> f -> g
- set :: ((f -> g) :-> (o -> i)) -> i -> f -> g
- traverse :: Functor m => ((f -> g) :-> (o -> i)) -> (o -> m i) -> f -> m g
- lifted :: Monad m => ((f -> g) :-> (m o -> m i)) -> ((o -> i) :-> (m a -> m b)) -> (f -> g) :-> (m a -> m b)
Documentation
type Total = (->)
Context that represents computations that always produce an output.
:: (f -> o) | Getter. |
-> ((o -> i) -> f -> g) | Modifier. |
-> (f -> g) :-> (o -> i) |
Create a total lens from a getter and a modifier.
We expect the following law to hold:
get l (set l a f) == a
set l (get l f) f == f