partial-lens-0.0.1: Haskell 98 Partial Lenses

Data.Lens.Partial.Lazy

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Synopsis

Documentation

joinMaybe :: MonadPlus m => m (Maybe a) -> m aSource

State actions

access :: Monad m => PartialLens a b -> StateT a m (Maybe b)Source

get the value of a partial lens into state

accessPlus :: MonadPlus m => PartialLens a b -> StateT a m bSource

returns mzero in case of a null reference

(~=) :: Monad m => PartialLens a b -> b -> StateT a m (Maybe b)Source

set a value using a partial lens into state returns Nothing in case of a null reference

(%=) :: Monad m => PartialLens a b -> (b -> b) -> StateT a m (Maybe b)Source

infix modification a value through a partial lens into state returns Nothing in case of a null reference

(%%=) :: Monad m => PartialLens a b -> (b -> (c, b)) -> StateT a m (Maybe c)Source

infix modification of a value through a partial lens into state with a supplemental response. returns Nothing in case of a null reference

(+=), (*=), (-=) :: (Monad m, Num b) => PartialLens a b -> b -> StateT a m (Maybe b)Source

(//=) :: (Monad m, Fractional b) => PartialLens a b -> b -> StateT a m (Maybe b)Source