base-4.8.1.0: Basic libraries

Copyright(c) Andy Gill 2001, (c) Oregon Graduate Institute of Science and Technology 2001
LicenseBSD-style (see the file LICENSE)
Maintainerross@soi.city.ac.uk
Stabilityexperimental
Portabilityportable
Safe HaskellTrustworthy
LanguageHaskell2010

Data.Functor.Identity

Description

The identity functor and monad.

This trivial type constructor serves two purposes:

  • It can be used with functions parameterized by functor or monad classes.
  • 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.

Since: 4.8.0.0

Synopsis

Documentation

newtype Identity a Source

Identity functor and monad. (a non-strict monad)

Since: 4.8.0.0

Constructors

Identity 

Fields

runIdentity :: a
 

Instances

Monad Identity 
Functor Identity 
MonadFix Identity 
Applicative Identity 
Foldable Identity 
Traversable Identity 
Generic1 Identity 
MonadZip Identity 
Eq a => Eq (Identity a) 
Data a => Data (Identity a) 
Ord a => Ord (Identity a) 
Read a => Read (Identity a)

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Show a => Show (Identity a)

This instance would be equivalent to the derived instances of the Identity newtype if the runIdentity field were removed

Generic (Identity a) 
type Rep1 Identity 
type Rep (Identity a)