Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
Generics.Deriving.Monoid
Contents
Synopsis
- class GSemigroup a => GMonoid a where
- gmemptydefault :: (Generic a, GMonoid' (Rep a)) => a
- gmappenddefault :: (Generic a, GMonoid' (Rep a)) => a -> a -> a
- class GSemigroup' f => GMonoid' f where
- memptydefault :: (Generic a, Monoid' (Rep a)) => a
- mappenddefault :: (Generic a, Monoid' (Rep a)) => a -> a -> a
- class Monoid' f where
- module Data.Monoid
Introduction
This module provides two main features:
GMonoid
, a generic version of theMonoid
type class, including instances of the types from Data.Monoid- Default generic definitions for the
Monoid
methodsmempty
andmappend
The generic defaults only work for types without alternatives (i.e. they have only one constructor). We cannot in general know how to deal with different constructors.
GMonoid type class
class GSemigroup a => GMonoid a where Source #
Minimal complete definition
Nothing
Methods
Generic mempty
gmappend :: a -> a -> a Source #
Generic mappend
Generic mconcat
gmempty :: (Generic a, GMonoid' (Rep a)) => a Source #
Generic mempty
gmappend :: (Generic a, GMonoid' (Rep a)) => a -> a -> a Source #
Generic mappend
Instances
Default definitions
GMonoid
Internal auxiliary class for GMonoid
class GSemigroup' f => GMonoid' f where Source #
Monoid
These functions can be used in a Monoid
instance. For example:
-- LANGUAGE DeriveGeneric import Generics.Deriving.Base (Generic) import Generics.Deriving.Monoid data T a = C a (Maybe a) deriving Generic instance Monoid a => Monoid (T a) where mempty = memptydefault mappend = mappenddefault
Internal auxiliary class for Monoid
The Monoid module
This is exported for convenient access to the various wrapper types.
module Data.Monoid
Orphan instances
GSemigroup a => GMonoid (Maybe a) Source # | |
GMonoid m => GMonoid (WrappedMonoid m) Source # | |
Methods gmempty :: WrappedMonoid m Source # gmappend :: WrappedMonoid m -> WrappedMonoid m -> WrappedMonoid m Source # gmconcat :: [WrappedMonoid m] -> WrappedMonoid m Source # |