| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Data.Semigroup.Compat
Contents
Description
This backports the modern Data.Semigroup interface back to
base-4.9/GHC 8.0.
- class Semigroup a where
- stimesMonoid :: (Integral b, Monoid a) => b -> a -> a
- stimesIdempotent :: Integral b => b -> a -> a
- stimesIdempotentMonoid :: (Integral b, Monoid a) => b -> a -> a
- mtimesDefault :: (Integral b, Monoid a) => b -> 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 {}
- newtype Any :: * = Any {}
- newtype Sum a :: * -> * = Sum {
- getSum :: a
- newtype Product a :: * -> * = Product {
- getProduct :: a
- newtype Option a :: * -> * = Option {}
- option :: b -> (a -> b) -> Option a -> b
- diff :: Semigroup m => m -> Endo m
- cycle1 :: Semigroup m => m -> m
- data Arg a b :: * -> * -> * = Arg a b
- type ArgMin a b = Min (Arg a b)
- type ArgMax a b = Max (Arg a b)
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) | |
stimesMonoid :: (Integral b, Monoid a) => b -> a -> a #
stimesIdempotent :: Integral b => b -> a -> a #
stimesIdempotentMonoid :: (Integral b, Monoid a) => b -> a -> a #
mtimesDefault :: (Integral b, Monoid a) => b -> a -> a #
Semigroups
Instances
| Monad Min | |
| Functor Min | |
| MonadFix Min | |
| Applicative Min | |
| Foldable Min | |
| Traversable Min | |
| Generic1 Min | |
| Bounded a => Bounded (Min a) | |
| Enum a => Enum (Min a) | |
| Eq a => Eq (Min a) | |
| Data a => Data (Min a) | |
| Num a => Num (Min a) | |
| Ord a => Ord (Min a) | |
| Read a => Read (Min a) | |
| Show a => Show (Min a) | |
| Generic (Min a) | |
| Ord a => Semigroup (Min a) | |
| (Ord a, Bounded a) => Monoid (Min a) | |
| type Rep1 Min | |
| type Rep (Min a) | |
Instances
| Monad Max | |
| Functor Max | |
| MonadFix Max | |
| Applicative Max | |
| Foldable Max | |
| Traversable Max | |
| Generic1 Max | |
| Bounded a => Bounded (Max a) | |
| Enum a => Enum (Max a) | |
| Eq a => Eq (Max a) | |
| Data a => Data (Max a) | |
| Num a => Num (Max a) | |
| Ord a => Ord (Max a) | |
| Read a => Read (Max a) | |
| Show a => Show (Max a) | |
| Generic (Max a) | |
| Ord a => Semigroup (Max a) | |
| (Ord a, Bounded a) => Monoid (Max a) | |
| type Rep1 Max | |
| type Rep (Max a) | |
Use to get the behavior of
Option (First a)First from Data.Monoid.
Instances
| Monad First | |
| Functor First | |
| MonadFix First | |
| Applicative First | |
| Foldable First | |
| Traversable First | |
| Generic1 First | |
| Bounded a => Bounded (First a) | |
| Enum a => Enum (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) | |
| Generic (First a) | |
| Semigroup (First a) | |
| type Rep1 First | |
| type Rep (First a) | |
Use to get the behavior of
Option (Last a)Last from Data.Monoid
Instances
| Monad Last | |
| Functor Last | |
| MonadFix Last | |
| Applicative Last | |
| Foldable Last | |
| Traversable Last | |
| Generic1 Last | |
| Bounded a => Bounded (Last a) | |
| Enum a => Enum (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) | |
| Generic (Last a) | |
| Semigroup (Last a) | |
| type Rep1 Last | |
| type Rep (Last a) | |
newtype WrappedMonoid m :: * -> * #
Provide a Semigroup for an arbitrary Monoid.
Constructors
| WrapMonoid | |
Fields
| |
Instances
| Generic1 WrappedMonoid | |
| Bounded a => Bounded (WrappedMonoid a) | |
| Enum a => Enum (WrappedMonoid a) | |
| 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) | |
| Generic (WrappedMonoid m) | |
| Monoid m => Semigroup (WrappedMonoid m) | |
| Monoid m => Monoid (WrappedMonoid m) | |
| type Rep1 WrappedMonoid | |
| type Rep (WrappedMonoid m) | |
Re-exported monoids from Data.Monoid
Instances
| Monad Dual | |
| Functor Dual | |
| Applicative Dual | |
| Foldable Dual | |
| Traversable Dual | |
| Generic1 Dual | |
| 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) | |
| Generic (Dual a) | |
| Semigroup a => Semigroup (Dual a) | |
| Monoid a => Monoid (Dual a) | |
| type Rep1 Dual | |
| type Rep (Dual a) | |
The monoid of endomorphisms under composition.
Boolean monoid under conjunction (&&).
Boolean monoid under disjunction (||).
Monoid under addition.
Instances
| Monad Sum | |
| Functor Sum | |
| Applicative Sum | |
| Foldable Sum | |
| Traversable Sum | |
| Generic1 Sum | |
| Bounded a => Bounded (Sum a) | |
| Eq a => Eq (Sum a) | |
| Num a => Num (Sum a) | |
| Ord a => Ord (Sum a) | |
| Read a => Read (Sum a) | |
| Show a => Show (Sum a) | |
| Generic (Sum a) | |
| Num a => Semigroup (Sum a) | |
| Num a => Monoid (Sum a) | |
| type Rep1 Sum | |
| type Rep (Sum a) | |
Monoid under multiplication.
Constructors
| Product | |
Fields
| |
Instances
| Monad Product | |
| Functor Product | |
| Applicative Product | |
| Foldable Product | |
| Traversable Product | |
| Generic1 Product | |
| Bounded a => Bounded (Product a) | |
| Eq a => Eq (Product a) | |
| Num a => Num (Product a) | |
| Ord a => Ord (Product a) | |
| Read a => Read (Product a) | |
| Show a => Show (Product a) | |
| Generic (Product a) | |
| Num a => Semigroup (Product a) | |
| Num a => Monoid (Product a) | |
| type Rep1 Product | |
| type Rep (Product a) | |
A better monoid for Maybe
Option is effectively Maybe with a better instance of
Monoid, built off of an underlying Semigroup instead of an
underlying Monoid.
Ideally, this type would not exist at all and we would just fix the
Monoid instance of Maybe
Instances
| Monad Option | |
| Functor Option | |
| MonadFix Option | |
| Applicative Option | |
| Foldable Option | |
| Traversable Option | |
| Generic1 Option | |
| Alternative Option | |
| MonadPlus 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) | |
| Generic (Option a) | |
| Semigroup a => Semigroup (Option a) | |
| Semigroup a => Monoid (Option a) | |
| type Rep1 Option | |
| type Rep (Option a) | |