Data.Functor.Plus

semigroupoids-1.2.6: Haskell 98 semigroupoids: Category sans id

Portability | portable
Stability | provisional
Maintainer | Edward Kmett <ekmett@gmail.com>

Data.Functor.Plus

Description

Synopsis

- class Alt f => Plus f where
  - zero :: f a
- module Data.Functor.Alt

# Documentation

class Alt f => Plus f where

Laws:

     zero <!> m = m
     m <!> zero = m

If extended to an `Alternative` then `zero` should equal `empty`.

Methods

zero :: f a

Instances

Plus [] |
Plus IO |
Plus Maybe |
Plus Seq |
Plus IntMap |
Plus Option |
MonadPlus m => Plus (WrappedMonad m) |
Ord k => Plus (Map k) |
(Bind f, Monad f) => Plus (MaybeT f) |
(Apply f, Applicative f) => Plus (ListT f) |
Plus f => Plus (IdentityT f) |
Alternative f => Plus (WrappedApplicative f) |
ArrowPlus a => Plus (WrappedArrow a b) |
Plus f => Plus (WriterT w f) |
Plus f => Plus (WriterT w f) |
Plus f => Plus (StateT e f) |
Plus f => Plus (StateT e f) |
Plus f => Plus (ReaderT e f) |
(Bind f, Monad f, Error e) => Plus (ErrorT e f) |
Plus f => Plus (Static f a) |
Plus f => Plus (RWST r w s f) |
Plus f => Plus (RWST r w s f) |

module Data.Functor.Alt