data-lens-fd-2.0.1: Lenses

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Data.Lens

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Synopsis

Documentation

module Data.Lens.Common

State API

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

get the value of a lens into state

(~=), (!=) :: MonadState a m => Lens a b -> b -> m bSource

set a value using a lens into state

(%=), (!%=) :: MonadState a m => Lens a b -> (b -> b) -> m bSource

infix modification a value through a lens into state

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

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

(+=), (!*=), (*=), (!-=), (-=), (!+=) :: (MonadState a m, Num b) => Lens a b -> b -> m bSource

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

(&&=), (!||=), (!&&=), (||=) :: MonadState a m => Lens a Bool -> Bool -> m BoolSource

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