Data.Lens

Documentation

module Data.Lens.Common

State API

access :: MonadState a m => Lens a b -> m b

get the value of a lens into state

(~=) :: MonadState a m => Lens a b -> b -> m b infixr 4

set a value using a lens into state

(!=) :: MonadState a m => Lens a b -> b -> m b infixr 4

set a value using a lens into state

(%=) :: MonadState a m => Lens a b -> (b -> b) -> m b infixr 4

infix modification a value through a lens into state

(!%=) :: MonadState a m => Lens a b -> (b -> b) -> m b infixr 4

infix modification a value through a lens into state

(%%=) :: MonadState a m => Lens a b -> (b -> (c, b)) -> m c infixr 4

infix modification of a value through a lens into state with a supplemental response

(!%%=) :: MonadState a m => Lens a b -> (b -> (c, b)) -> m c infixr 4

infix modification of a value through a lens into state with a supplemental response

(+=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(!+=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(-=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(!-=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(*=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(!*=) :: (MonadState a m, Num b) => Lens a b -> b -> m b infixr 4

(//=) :: (MonadState a m, Fractional b) => Lens a b -> b -> m b infixr 4

(!/=) :: (MonadState a m, Fractional b) => Lens a b -> b -> m b infixr 4

(&&=) :: MonadState a m => Lens a Bool -> Bool -> m Bool infixr 4

(!&&=) :: MonadState a m => Lens a Bool -> Bool -> m Bool infixr 4

(||=) :: MonadState a m => Lens a Bool -> Bool -> m Bool infixr 4

(!||=) :: MonadState a m => Lens a Bool -> Bool -> m Bool infixr 4

focus :: Monad m => Lens a b -> StateT b m c -> StateT a m c