fused-effects-lens-1.0.0.0: Monadic lens combinators for fused-effects.

Safe HaskellNone
LanguageHaskell2010

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

Documentation

view :: forall r a sig m. Has (Reader r) sig m => Getting a r a -> m a Source #

View the value pointed to by a Getter, Lens, Traversal, or Fold corresponding to the Reader context of the given monadic carrier.

views :: forall s a b sig m. Has (Reader s) sig 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. Has (State s) sig m => Getting a s a -> m a Source #

Extract the target of a Lens or Getter, or use a summary of a Fold or Traversal that points to a monoidal value.

uses :: forall s a b f sig. Has (State s) sig f => Getting a s a -> (a -> b) -> f b Source #

Use a function of the target of a Lens or Getter in the current state, or use a summary of a Fold or Traversal that points to a monoidal value.

assign :: forall s a b sig m. Has (State s) sig 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. Has (State s) sig 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.

modifying :: forall s a b sig m. Has (State s) sig m => ASetter s s a b -> (a -> b) -> m () Source #

Map over the target of a Lens, or all of the targets of a Setter or Traversal, in the current monadic state.

This is a prefix version of %=.

(%=) :: forall s a b sig m. Has (State s) sig m => ASetter s s a b -> (a -> b) -> m () infixr 4 Source #

Map over the target of a Lens, or all of the targets of a Setter or Traversal, in the current monadic state.

This is an infix version of modifying.