| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Control.Effect.Lens
Description
Provides combinators for the lens-based manipulation of state and context types provided by the fused-effects library, similar to those provided for mtl-based monad transformers.
Synopsis
- view :: forall r a sig m. (Member (Reader r) sig, Carrier sig m, Functor m) => Getting a r a -> m a
- views :: forall s a b sig m. (Member (Reader s) sig, Carrier sig m, Functor m) => Getting a s a -> (a -> b) -> m b
- use :: forall s a sig m. (Member (State s) sig, Carrier sig m, Monad m) => Getting a s a -> m a
- uses :: forall s a b f sig. (Carrier sig f, Functor f, Member (State s) sig) => Getting a s a -> (a -> b) -> f b
- assign :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> b -> m ()
- (.=) :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> b -> m ()
- modifying :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> (a -> b) -> m ()
- (%=) :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> (a -> b) -> m ()
Documentation
view :: forall r a sig m. (Member (Reader r) sig, Carrier sig m, Functor m) => Getting a r a -> m a Source #
View the value pointed to by a getter or lens, or the result
of folding over all the results of a fold or traversal, when
applied to the Reader context of the given monadic carrier.
views :: forall s a b sig m. (Member (Reader s) sig, Carrier sig m, Functor m) => Getting a s a -> (a -> b) -> m b Source #
View a function of the value pointed to by a getter or lens,
or the result of folding over all the results of a fold or
traversal, when applied to the Reader context of the given
monadic carrier.
This is slightly more general in lens itself, but should suffice for our purposes.
use :: forall s a sig m. (Member (State s) sig, Carrier sig m, Monad m) => Getting a s a -> m a Source #
Extract the target of a lens or getter, or the result
of folding over all the results of a fold or traversal,
applied to the State context of the the given monadic carrier.
uses :: forall s a b f sig. (Carrier sig f, Functor f, Member (State s) sig) => Getting a s a -> (a -> b) -> f b Source #
Extract a function of the target of a lens or getter, or the
result of folding over all the results of a fold or traversal,
applied to the State context of the the given monadic carrier.
assign :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> b -> m () Source #
Replace the target of a lens (or all the targets of a setter or traversal) within the current monadic state, irrespective of the old value.
This is a prefix version of .=.
(.=) :: forall s a b sig m. (Member (State s) sig, Carrier sig m, Monad m) => ASetter s s a b -> b -> m () infixr 4 Source #
Replace the target of a lens (or all the targets of a setter or traversal) within the current monadic state, irrespective of the old value.
This is an infix version of assign.