Portability | portable |
---|---|

Stability | experimental |

Maintainer | libraries@haskell.org |

The identity functor and monad.

This trivial type constructor serves two purposes:

- It can be used with functions parameterized by a
`Functor`

or`Monad`

. - It can be used as a base monad to which a series of monad
transformers may be applied to construct a composite monad.
Most monad transformer modules include the special case of
applying the transformer to
`Identity`

. For example,`State s`

is an abbreviation for`StateT s`

.`Identity`

- newtype Identity a = Identity {
- runIdentity :: a