| Copyright | (c) Ross Paterson 2010 |
|---|---|
| License | BSD-style (see the file LICENSE) |
| Maintainer | ross@soi.city.ac.uk |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell98 |
Control.Applicative.Lift
Contents
Description
Adding a new kind of pure computation to an applicative functor.
Documentation
Applicative functor formed by adding pure computations to a given applicative functor.
Instances
| Alternative f => Alternative (Lift f) | A combination is |
| Functor f => Functor (Lift f) | |
| Applicative f => Applicative (Lift f) | A combination is |
| Foldable f => Foldable (Lift f) | |
| Traversable f => Traversable (Lift f) |
unLift :: Applicative f => Lift f a -> f aSource
Projection to the other functor.
Collecting errors
type Errors e = Lift (Constant e)Source
An applicative functor that collects a monoid (e.g. lists) of errors.
A sequence of computations fails if any of its components do, but
unlike monads made with ErrorT from Control.Monad.Trans.Error,
these computations continue after an error, collecting all the errors.