Optics.State.Operators

Defines infix operators for the operations in Optics.State. These operators are not exposed by the main Optics module, but must be imported explicitly.

State modifying optics

(.=) :: (Is k A_Setter, MonadState s m) => Optic k is s s a b -> b -> m () infix 4

Replace the target(s) of an Optic in our monadic state with a new value, irrespective of the old.

This is an infix version of assign.

(?=) :: (Is k A_Setter, MonadState s m) => Optic k is s s (Maybe a) (Maybe b) -> b -> m () infix 4

Replace the target(s) of an Optic in our monadic state with Just a new value, irrespective of the old.

(%=) :: (Is k A_Setter, MonadState s m) => Optic k is s s a b -> (a -> b) -> m () infix 4

Map over the target(s) of an Optic in our monadic state.

This is an infix version of modifying.

State modifying optics with passthrough

(%%=) :: (PermeableOptic k r, MonadState s m) => Optic k is s s a b -> (a -> (r, b)) -> m (ViewResult k r) infix 4

Modify the target of an PermeableOptic in the current state returning some extra information of type depending on the optic (r, Maybe r or monoidal summary).

Returning new value

(<.=) :: (PermeableOptic k b, MonadState s m) => Optic k is s s a b -> b -> m (ViewResult k b) infix 4

Set with pass-through.

This is useful for chaining assignment without round-tripping through your Monad stack.

(<?=) :: (PermeableOptic k (Maybe b), MonadState s m) => Optic k is s s (Maybe a) (Maybe b) -> b -> m (ViewResult k (Maybe b)) infix 4

Set Just a value with pass-through.

This is useful for chaining assignment without round-tripping through your Monad stack.

(<%=) :: (PermeableOptic k b, MonadState s m) => Optic k is s s a b -> (a -> b) -> m (ViewResult k b) infix 4

Modify the target of a PermeableOptic into your Monad's state by a user supplied function and return the result.

Returning old value

(<<.=) :: (PermeableOptic k a, MonadState s m) => Optic k is s s a b -> b -> m (ViewResult k a) infix 4

Replace the target of a PermeableOptic into your Monad's state with a user supplied value and return the old value that was replaced.

(<<?=) :: (PermeableOptic k (Maybe a), MonadState s m) => Optic k is s s (Maybe a) (Maybe b) -> b -> m (ViewResult k (Maybe a)) infix 4

Replace the target of a PermeableOptic into your Monad's state with Just a user supplied value and return the old value that was replaced.

(<<%=) :: (PermeableOptic k a, MonadState s m) => Optic k is s s a b -> (a -> b) -> m (ViewResult k a) infix 4

Modify the target of a PermeableOptic into your Monad's state by a user supplied function and return the old value that was replaced.

Passthrough

class (Is k A_Traversal, ViewableOptic k r) => PermeableOptic k r where

Methods

passthrough :: Optic k is s t a b -> (a -> (r, b)) -> s -> (ViewResult k r, t)

Modify the target of an Optic returning extra information of type r.

Instances

PermeableOptic An_Iso r

Defined in Optics.Passthrough

Methods

passthrough :: forall (is :: IxList) s t a b. Optic An_Iso is s t a b -> (a -> (r, b)) -> s -> (ViewResult An_Iso r, t)

PermeableOptic A_Lens r

Defined in Optics.Passthrough

Methods

passthrough :: forall (is :: IxList) s t a b. Optic A_Lens is s t a b -> (a -> (r, b)) -> s -> (ViewResult A_Lens r, t)

PermeableOptic A_Prism r

Defined in Optics.Passthrough

Methods

passthrough :: forall (is :: IxList) s t a b. Optic A_Prism is s t a b -> (a -> (r, b)) -> s -> (ViewResult A_Prism r, t)

PermeableOptic An_AffineTraversal r

Defined in Optics.Passthrough

Methods

passthrough :: forall (is :: IxList) s t a b. Optic An_AffineTraversal is s t a b -> (a -> (r, b)) -> s -> (ViewResult An_AffineTraversal r, t)

Monoid r => PermeableOptic A_Traversal r

Defined in Optics.Passthrough

Methods

passthrough :: forall (is :: IxList) s t a b. Optic A_Traversal is s t a b -> (a -> (r, b)) -> s -> (ViewResult A_Traversal r, t)