| Safe Haskell | Safe | 
|---|---|
| Language | Haskell2010 | 
Algebra
- class Semigroup a where
 - class Monoid a where
 - class Monoid a => Group a where
 - class Semigroup a => Abelian a
 - class Semigroup a => Idempotent a
 - (+) :: Semigroup (Sum a) => a -> a -> a
 - (-) :: (Semigroup (Sum a), Group (Sum a)) => a -> a -> a
 - (*) :: Semigroup (Product a) => a -> a -> a
 - (/) :: (Semigroup (Product a), Group (Product a)) => a -> a -> a
 
Documentation
The class of semigroups (types with an associative binary operation).
Since: 4.9.0.0
Methods
(<>) :: a -> a -> a infixr 6 #
An associative operation.
(a<>b)<>c = a<>(b<>c)
If a is also a Monoid we further require
(<>) =mappend
Reduce a non-empty list with <>
The default definition should be sufficient, but this can be overridden for efficiency.
stimes :: Integral b => b -> a -> a #
Repeat a value n times.
Given that this works on a Semigroup it is allowed to fail if
 you request 0 or fewer repetitions, and the default definition
 will do so.
By making this a member of the class, idempotent semigroups and monoids can
 upgrade this to execute in O(1) by picking
 stimes = stimesIdempotent or stimes = stimesIdempotentMonoid
 respectively.
Instances
| Semigroup Ordering | |
| Semigroup () | |
| Semigroup Void | |
| Semigroup All | |
| Semigroup Any | |
| Semigroup [a] | |
| Semigroup a => Semigroup (Maybe a) | |
| Semigroup a => Semigroup (Identity a) | |
| Ord a => Semigroup (Min a) | |
| Ord a => Semigroup (Max a) | |
| Semigroup (First a) | |
| Semigroup (Last a) | |
| Monoid m => Semigroup (WrappedMonoid m) | |
| Semigroup a => Semigroup (Option a) | |
| Semigroup (NonEmpty a) | |
| Semigroup a => Semigroup (Dual a) | |
| Semigroup (Endo a) | |
| Num a => Semigroup (Sum a) | |
| Num a => Semigroup (Product a) | |
| Semigroup (First a) | |
| Semigroup (Last a) | |
| Semigroup b => Semigroup (a -> b) | |
| Semigroup (Either a b) | |
| (Semigroup a, Semigroup b) => Semigroup (a, b) | |
| Semigroup (Proxy k s) | |
| (Semigroup a, Semigroup b, Semigroup c) => Semigroup (a, b, c) | |
| Semigroup a => Semigroup (Const k a b) | |
| Alternative f => Semigroup (Alt * f a) | |
| (Semigroup a, Semigroup b, Semigroup c, Semigroup d) => Semigroup (a, b, c, d) | |
| (Semigroup a, Semigroup b, Semigroup c, Semigroup d, Semigroup e) => Semigroup (a, b, c, d, e) | |
The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following laws:
mappend mempty x = x
mappend x mempty = x
mappend x (mappend y z) = mappend (mappend x y) z
mconcat =
foldrmappend mempty
The method names refer to the monoid of lists under concatenation, but there are many other instances.
Some types can be viewed as a monoid in more than one way,
 e.g. both addition and multiplication on numbers.
 In such cases we often define newtypes and make those instances
 of Monoid, e.g. Sum and Product.
Instances
| Monoid Ordering | |
| Monoid () | |
| Monoid All | |
| Monoid Any | |
| Monoid [a] | |
| Monoid a => Monoid (Maybe a) | Lift a semigroup into   | 
| Monoid a => Monoid (IO a) | |
| Monoid a => Monoid (Identity a) | |
| (Ord a, Bounded a) => Monoid (Min a) | |
| (Ord a, Bounded a) => Monoid (Max a) | |
| Monoid m => Monoid (WrappedMonoid m) | |
| Semigroup a => Monoid (Option a) | |
| Monoid a => Monoid (Dual a) | |
| Monoid (Endo a) | |
| Num a => Monoid (Sum a) | |
| Num a => Monoid (Product a) | |
| Monoid (First a) | |
| Monoid (Last a) | |
| Monoid b => Monoid (a -> b) | |
| (Monoid a, Monoid b) => Monoid (a, b) | |
| Monoid (Proxy k s) | |
| (Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) | |
| Monoid a => Monoid (Const k a b) | |
| Alternative f => Monoid (Alt * f a) | |
| (Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) | |
| (Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) | |
class Monoid a => Group a where Source #
Minimal complete definition
Instances
| Group () Source # | |
| Group a => Group (Identity a) Source # | |
| Group a => Group (Dual a) Source # | |
| Group (Sum Int) Source # | |
| Group (Sum Integer) Source # | |
| Group (Sum Word) Source # | |
| Group b => Group (a -> b) Source # | |
| (Group a, Group b) => Group (a, b) Source # | |
| Group (Proxy k a) Source # | |
| (Group a, Group b, Group c) => Group (a, b, c) Source # | |
| Group a => Group (Const k a b) Source # | |
| (Group a, Group b, Group c, Group d) => Group (a, b, c, d) Source # | |
| (Group a, Group b, Group c, Group d, Group e) => Group (a, b, c, d, e) Source # | |
class Semigroup a => Abelian a Source #
Instances
class Semigroup a => Idempotent a Source #
Instances
| Idempotent () Source # | |
| Idempotent a => Idempotent (Identity a) Source # | |
| Ord a => Idempotent (Min a) Source # | |
| Ord a => Idempotent (Max a) Source # | |
| Idempotent a => Idempotent (Dual a) Source # | |
| Idempotent b => Idempotent (a -> b) Source # | |
| (Idempotent a, Idempotent b) => Idempotent (a, b) Source # | |
| Idempotent (Proxy k a) Source # | |
| (Idempotent a, Idempotent b, Idempotent c) => Idempotent (a, b, c) Source # | |
| Idempotent a => Idempotent (Const k a b) Source # | |
| (Idempotent a, Idempotent b, Idempotent c, Idempotent d) => Idempotent (a, b, c, d) Source # | |
| (Idempotent a, Idempotent b, Idempotent c, Idempotent d, Idempotent e) => Idempotent (a, b, c, d, e) Source # | |