Copyright	(C) 2014-2015 Edward Kmett Eric Mertens
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	provisional
Portability	portable
Safe Haskell	Safe
Language	Haskell98

Data.Semigroup.Generic

Contents

Generic method implementations
Adapter newtype
Internal classes

Description

This module provides generic deriving tools for monoids and semigroups for product-like structures.

Synopsis

gmappend :: (Generic a, GSemigroup (Rep a)) => a -> a -> a
gmempty :: (Generic a, GMonoid (Rep a)) => a
newtype GenericSemigroupMonoid a = GenericSemigroupMonoid {
- getGenericSemigroupMonoid :: a
}
class GSemigroup f
class GSemigroup f => GMonoid f

Generic method implementations

gmappend :: (Generic a, GSemigroup (Rep a)) => a -> a -> a #

Generically generate a Semigroup (<>) operation for any type implementing Generic. This operation will append two values by point-wise appending their component fields. It is only defined for product types.

gmappend a (gmappend b c) = gmappend (gmappend a b) c

gmempty :: (Generic a, GMonoid (Rep a)) => a #

Generically generate a Monoid mempty for any product-like type implementing Generic.

It is only defined for product types.

gmappend gmempty a = a = gmappend a gmempty

Adapter newtype

newtype GenericSemigroupMonoid a #

An adapter newtype, suitable for DerivingVia. Its Semigroup and Monoid instances leverage the Generic-based defaults defined by gmappend and gmempty. Here is an example of how to use it:

{-# LANGUAGE DerivingVia #-}
import Data.Semigroup.Generic

data Pair a = MkPair a a
  deriving (Semigroup, Monoid) via (GenericSemigroupMonoid (Pair a))

Constructors

GenericSemigroupMonoid
Fields getGenericSemigroupMonoid :: a

Instances

Instances details

(Generic a, GSemigroup (Rep a)) => Semigroup (GenericSemigroupMonoid a) #
Instance details Defined in Data.Semigroup.Generic Methods (<>) :: GenericSemigroupMonoid a -> GenericSemigroupMonoid a -> GenericSemigroupMonoid a sconcat :: NonEmpty (GenericSemigroupMonoid a) -> GenericSemigroupMonoid a stimes :: Integral b => b -> GenericSemigroupMonoid a -> GenericSemigroupMonoid a
(Generic a, GMonoid (Rep a)) => Monoid (GenericSemigroupMonoid a) #
Instance details Defined in Data.Semigroup.Generic Methods mempty :: GenericSemigroupMonoid a mappend :: GenericSemigroupMonoid a -> GenericSemigroupMonoid a -> GenericSemigroupMonoid a mconcat :: [GenericSemigroupMonoid a] -> GenericSemigroupMonoid a

Internal classes

class GSemigroup f #

Minimal complete definition

gmappend'

Instances

Instances details

GSemigroup (V1 :: Type -> Type) #
Instance details Defined in Data.Semigroup.Generic Methods gmappend' :: V1 p -> V1 p -> V1 p
GSemigroup (U1 :: Type -> Type) #
Instance details Defined in Data.Semigroup.Generic Methods gmappend' :: U1 p -> U1 p -> U1 p
Semigroup a => GSemigroup (K1 i a :: Type -> Type) #
Instance details Defined in Data.Semigroup.Generic Methods gmappend' :: K1 i a p -> K1 i a p -> K1 i a p
(GSemigroup f, GSemigroup g) => GSemigroup (f :*: g) #
Instance details Defined in Data.Semigroup.Generic Methods gmappend' :: (f :: g) p -> (f :: g) p -> (f :*: g) p
GSemigroup f => GSemigroup (M1 i c f) #
Instance details Defined in Data.Semigroup.Generic Methods gmappend' :: M1 i c f p -> M1 i c f p -> M1 i c f p

class GSemigroup f => GMonoid f #

Minimal complete definition

gmempty'

Instances

Instances details

GMonoid (U1 :: Type -> Type) #
Instance details Defined in Data.Semigroup.Generic Methods gmempty' :: U1 p
(Semigroup a, Monoid a) => GMonoid (K1 i a :: Type -> Type) #
Instance details Defined in Data.Semigroup.Generic Methods gmempty' :: K1 i a p
(GMonoid f, GMonoid g) => GMonoid (f :*: g) #
Instance details Defined in Data.Semigroup.Generic Methods gmempty' :: (f :*: g) p
GMonoid f => GMonoid (M1 i c f) #
Instance details Defined in Data.Semigroup.Generic Methods gmempty' :: M1 i c f p