Copyright	(C) 2011-2015 Edward Kmett
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	provisional
Portability	portable
Safe Haskell	Trustworthy
Language	Haskell2010

Data.Functor.Plus

Description

Synopsis

class Alt f => Plus f where
- zero :: f a
psum :: (Foldable t, Plus f) => t (f a) -> f a
module Data.Functor.Alt

Documentation

class Alt f => Plus f where Source #

Laws:

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

If extended to an Alternative then zero should equal empty.

Methods

zero :: f a Source #

Instances

Instances details

Plus [] Source #
Instance details Defined in Data.Functor.Plus Methods zero :: [a] Source #
Plus Maybe Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Maybe a Source #
Plus IO Source #
Instance details Defined in Data.Functor.Plus Methods zero :: IO a Source #
Plus Option Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Option a Source #
Plus First Source #
Instance details Defined in Data.Functor.Plus Methods zero :: First a Source #
Plus Last Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Last a Source #
Plus IntMap Source #
Instance details Defined in Data.Functor.Plus Methods zero :: IntMap a Source #
Plus Seq Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Seq a Source #
Plus (U1 :: Type -> Type) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: U1 a Source #
MonadPlus m => Plus (WrappedMonad m) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: WrappedMonad m a Source #
Plus (Proxy :: Type -> Type) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Proxy a Source #
Ord k => Plus (Map k) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Map k a Source #
Plus f => Plus (Lift f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Lift f a Source #
(Functor f, Monad f) => Plus (MaybeT f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: MaybeT f a Source #
(Apply f, Applicative f) => Plus (ListT f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: ListT f a Source #
(Hashable k, Eq k) => Plus (HashMap k) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: HashMap k a Source #
Alternative f => Plus (WrappedApplicative f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: WrappedApplicative f a Source #
Plus f => Plus (Rec1 f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Rec1 f a Source #
ArrowPlus a => Plus (WrappedArrow a b) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: WrappedArrow a b a0 Source #
Plus f => Plus (IdentityT f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: IdentityT f a Source #
Plus f => Plus (Reverse f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Reverse f a Source #
Plus f => Plus (WriterT w f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: WriterT w f a Source #
Plus f => Plus (WriterT w f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: WriterT w f a Source #
Plus f => Plus (WriterT w f) Source #	Since: 5.3.6
Instance details Defined in Data.Functor.Plus Methods zero :: WriterT w f a Source #
Plus f => Plus (StateT e f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: StateT e f a Source #
Plus f => Plus (StateT e f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: StateT e f a Source #
Plus f => Plus (ReaderT e f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: ReaderT e f a Source #
(Functor f, Monad f, Semigroup e, Monoid e) => Plus (ExceptT e f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: ExceptT e f a Source #
(Functor f, Monad f, Error e) => Plus (ErrorT e f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: ErrorT e f a Source #
Plus f => Plus (Backwards f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Backwards f a Source #
Plus f => Plus (Static f a) Source #
Instance details Defined in Data.Semigroupoid.Static Methods zero :: Static f a a0 Source #
(Plus f, Plus g) => Plus (f :*: g) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: (f :*: g) a Source #
(Plus f, Plus g) => Plus (Product f g) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Product f g a Source #
Plus f => Plus (M1 i c f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: M1 i c f a Source #
(Plus f, Functor g) => Plus (Compose f g) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: Compose f g a Source #
Plus f => Plus (RWST r w s f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: RWST r w s f a Source #
Plus f => Plus (RWST r w s f) Source #
Instance details Defined in Data.Functor.Plus Methods zero :: RWST r w s f a Source #
Plus f => Plus (RWST r w s f) Source #	Since: 5.3.6
Instance details Defined in Data.Functor.Plus Methods zero :: RWST r w s f a Source #

psum :: (Foldable t, Plus f) => t (f a) -> f a Source #

The sum of a collection of actions, generalizing concat.

>>> psum [Just "Hello", Nothing, Just "World"]
Just "Hello"

Since: 5.3.6

module Data.Functor.Alt