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

Data.Semigroup

Contents

Semigroups
Monoids from Data.Monoid
A better monoid for Maybe
Difference lists of a semigroup

Description

Synopsis

class Semigroup a where
- (<>) :: a -> a -> a
newtype Min a = Min {
- getMin :: a
}
newtype Max a = Max {
- getMax :: a
}
newtype First a = First {
- getFirst :: a
}
newtype Last a = Last {
- getLast :: a
}
newtype WrappedMonoid m = WrapMonoid {
- unwrapMonoid :: m
}
newtype Dual a = Dual {
- getDual :: a
}
newtype Endo a = Endo {
- appEndo :: a -> a
}
newtype All = All {
- getAll :: Bool
}
newtype Any = Any {
- getAny :: Bool
}
newtype Sum a = Sum {
- getSum :: a
}
newtype Product a = Product {
- getProduct :: a
}
newtype Option a = Option {
- getOption :: Maybe a
}
option :: b -> (a -> b) -> Option a -> b
diff :: Semigroup m => m -> Endo m

Documentation

class Semigroup a whereSource

Methods

(<>) :: a -> a -> aSource

Instances

Semigroup [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 a => Semigroup (Maybe a)

Semigroup (Seq a)

Semigroup (IntMap v)

Ord a => Semigroup (Set a)

Semigroup (Proxy a)

Semigroup a => Semigroup (Option a)

Monoid m => Semigroup (WrappedMonoid m)

Semigroup (Last a)

Semigroup (First a)

Ord a => Semigroup (Max a)

Ord a => Semigroup (Min a)

Semigroup b => Semigroup (a -> b)

Semigroup (Either a b)

(Semigroup a, Semigroup b) => Semigroup (a, b)

Ord k => Semigroup (Map k v)

Semigroup a => Semigroup (Tagged s a)

(Semigroup a, Semigroup b, Semigroup c) => Semigroup (a, b, c)

(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)

Semigroups

newtype Min a Source

Constructors

Min

Fields

getMin :: a

Instances

Typeable1 Min

Bounded a => Bounded (Min a)

Eq a => Eq (Min a)

Data a => Data (Min a)

Ord a => Ord (Min a)

Read a => Read (Min a)

Show a => Show (Min a)

(Ord a, Bounded a) => Monoid (Min a)

Ord a => Semigroup (Min a)

newtype Max a Source

Constructors

Max

Fields

getMax :: a

Instances

Typeable1 Max

Bounded a => Bounded (Max a)

Eq a => Eq (Max a)

Data a => Data (Max a)

Ord a => Ord (Max a)

Read a => Read (Max a)

Show a => Show (Max a)

(Ord a, Bounded a) => Monoid (Max a)

Ord a => Semigroup (Max a)

newtype First a Source

Use Option (First a) -- to get the behavior of Data.Monoid.First

Constructors

First

Fields

getFirst :: a

Instances

Typeable1 First

Bounded a => Bounded (First a)

Eq a => Eq (First a)

Data a => Data (First a)

Ord a => Ord (First a)

Read a => Read (First a)

Show a => Show (First a)

Semigroup (First a)

newtype Last a Source

Use Option (Last a) -- to get the behavior of Data.Monoid.Last

Constructors

Last

Fields

getLast :: a

Instances

Typeable1 Last

Bounded a => Bounded (Last a)

Eq a => Eq (Last a)

Data a => Data (Last a)

Ord a => Ord (Last a)

Read a => Read (Last a)

Show a => Show (Last a)

Semigroup (Last a)

newtype WrappedMonoid m Source

Constructors

WrapMonoid

Fields

unwrapMonoid :: m

Instances

Typeable1 WrappedMonoid

Eq m => Eq (WrappedMonoid m)

Data m => Data (WrappedMonoid m)

Ord m => Ord (WrappedMonoid m)

Read m => Read (WrappedMonoid m)

Show m => Show (WrappedMonoid m)

Monoid m => Monoid (WrappedMonoid m)

Monoid m => Semigroup (WrappedMonoid m)

Monoids from Data.Monoid

newtype Dual a

The dual of a monoid, obtained by swapping the arguments of mappend .

Constructors

Dual

Fields

getDual :: a

Instances

Bounded a => Bounded (Dual a)

Eq a => Eq (Dual a)

Ord a => Ord (Dual a)

Read a => Read (Dual a)

Show a => Show (Dual a)

Monoid a => Monoid (Dual a)

Semigroup a => Semigroup (Dual a)

newtype Endo a

The monoid of endomorphisms under composition.

Constructors

Endo

Fields

appEndo :: a -> a

Instances

Monoid (Endo a)

Semigroup (Endo a)

newtype All

Boolean monoid under conjunction.

Constructors

All

Fields

getAll :: Bool

Instances

Bounded All

Eq All

Ord All

Read All

Show All

Monoid All

Semigroup All

newtype Any

Boolean monoid under disjunction.

Constructors

Any

Fields

getAny :: Bool

Instances

Bounded Any

Eq Any

Ord Any

Read Any

Show Any

Monoid Any

Semigroup Any

newtype Sum a

Monoid under addition.

Constructors

Sum

Fields

getSum :: a

Instances

Bounded a => Bounded (Sum a)

Eq a => Eq (Sum a)

Ord a => Ord (Sum a)

Read a => Read (Sum a)

Show a => Show (Sum a)

Num a => Monoid (Sum a)

Num a => Semigroup (Sum a)

newtype Product a

Monoid under multiplication.

Constructors

Product

Fields

getProduct :: a

Instances

Bounded a => Bounded (Product a)

Eq a => Eq (Product a)

Ord a => Ord (Product a)

Read a => Read (Product a)

Show a => Show (Product a)

Num a => Monoid (Product a)

Num a => Semigroup (Product a)

A better monoid for Maybe

newtype Option a Source

Option is effectively Maybe with a better instance of Monoid , built off of an underlying Semigroup instead of an underlying Monoid .

Constructors

Option

Fields

getOption :: Maybe a

Instances

Monad Option

Eq a => Eq (Option a)

Data a => Data (Option a)

Ord a => Ord (Option a)

Read a => Read (Option a)

Show a => Show (Option a)

Semigroup a => Monoid (Option a)

Semigroup a => Semigroup (Option a)

option :: b -> (a -> b) -> Option a -> bSource

Difference lists of a semigroup

diff :: Semigroup m => m -> Endo mSource

This lets you use a 'difference list' of a semigroup as a Monoid.