Safe Haskell	Safe-Inferred
Language	GHC2021

Data.PartialSemigroup.Generics

Contents

The generic PartialSemigroup operator
Implementation details
Re-exports

Description

If a type derives Generic and all of its fields have PartialSemigroup instances, you can get a PartialSemigroup for free using genericPartialSemigroupOp.

Example

For this demonstration we'll define a contrived example type T with two constructors, A and B.

>>> data T = A String (Either String String) | B String deriving (Generic, Show)

And then define its PartialSemigroup instance using genericPartialSemigroupOp.

>>> instance PartialSemigroup T where (<>?) = genericPartialSemigroupOp

This gives us an implementation of <>? which combines values only if they have the same structure.

>>> A "s" (Left "x") <>? A "t" (Left "y")
Just (A "st" (Left "xy"))

>>> B "x" <>? B "y"
Just (B "xy")

For values that do not have the same structure, <>? produces Nothing.

>>> A "s" (Left "x") <>? A "t" (Right "y")
Nothing

>>> A "x" (Left "y") <>? B "z"
Nothing

Synopsis

genericPartialSemigroupOp :: (Generic a, PartialSemigroupRep (Rep a)) => a -> a -> Maybe a
class PartialSemigroupRep rep where
- repPartialSemigroupOp :: rep a -> rep a -> Maybe (rep a)
class Generic a
class PartialSemigroup a where
- (<>?) :: a -> a -> Maybe a

The generic PartialSemigroup operator

genericPartialSemigroupOp :: (Generic a, PartialSemigroupRep (Rep a)) => a -> a -> Maybe a Source #

Implementation details

class PartialSemigroupRep rep where Source #

The class of generic type Reps for which we can automatically derive PartialSemigroup:

K1 - a single value
M1 - a value with some additional metadata (which we simply discard)
:+: - sum types
:*: - product types

Methods

repPartialSemigroupOp :: rep a -> rep a -> Maybe (rep a) Source #

Instances

Instances details

(PartialSemigroupRep rep1, PartialSemigroupRep rep2) => PartialSemigroupRep (rep1 :*: rep2 :: k -> Type) Source #
Instance details Defined in Data.PartialSemigroup.Generics Methods repPartialSemigroupOp :: forall (a :: k0). (rep1 :: rep2) a -> (rep1 :: rep2) a -> Maybe ((rep1 :*: rep2) a) Source #
(PartialSemigroupRep rep1, PartialSemigroupRep rep2) => PartialSemigroupRep (rep1 :+: rep2 :: k -> Type) Source #
Instance details Defined in Data.PartialSemigroup.Generics Methods repPartialSemigroupOp :: forall (a :: k0). (rep1 :+: rep2) a -> (rep1 :+: rep2) a -> Maybe ((rep1 :+: rep2) a) Source #
PartialSemigroup a => PartialSemigroupRep (K1 i a :: k -> Type) Source #
Instance details Defined in Data.PartialSemigroup.Generics Methods repPartialSemigroupOp :: forall (a0 :: k0). K1 i a a0 -> K1 i a a0 -> Maybe (K1 i a a0) Source #
PartialSemigroupRep rep => PartialSemigroupRep (M1 i meta rep :: k -> Type) Source #
Instance details Defined in Data.PartialSemigroup.Generics Methods repPartialSemigroupOp :: forall (a :: k0). M1 i meta rep a -> M1 i meta rep a -> Maybe (M1 i meta rep a) Source #

Re-exports

class Generic a #

Representable types of kind *. This class is derivable in GHC with the DeriveGeneric flag on.

A Generic instance must satisfy the following laws:

from . to ≡ id
to . from ≡ id

Minimal complete definition

from, to

Instances

Instances details

Generic All
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep All :: Type -> Type # Methods from :: All -> Rep All x # to :: Rep All x -> All #
Generic Any
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep Any :: Type -> Type # Methods from :: Any -> Rep Any x # to :: Rep Any x -> Any #
Generic Fingerprint
Instance details Defined in GHC.Generics Associated Types type Rep Fingerprint :: Type -> Type # Methods from :: Fingerprint -> Rep Fingerprint x # to :: Rep Fingerprint x -> Fingerprint #
Generic Associativity
Instance details Defined in GHC.Generics Associated Types type Rep Associativity :: Type -> Type # Methods from :: Associativity -> Rep Associativity x # to :: Rep Associativity x -> Associativity #
Generic DecidedStrictness
Instance details Defined in GHC.Generics Associated Types type Rep DecidedStrictness :: Type -> Type # Methods from :: DecidedStrictness -> Rep DecidedStrictness x # to :: Rep DecidedStrictness x -> DecidedStrictness #
Generic Fixity
Instance details Defined in GHC.Generics Associated Types type Rep Fixity :: Type -> Type # Methods from :: Fixity -> Rep Fixity x # to :: Rep Fixity x -> Fixity #
Generic SourceStrictness
Instance details Defined in GHC.Generics Associated Types type Rep SourceStrictness :: Type -> Type # Methods from :: SourceStrictness -> Rep SourceStrictness x # to :: Rep SourceStrictness x -> SourceStrictness #
Generic SourceUnpackedness
Instance details Defined in GHC.Generics Associated Types type Rep SourceUnpackedness :: Type -> Type # Methods from :: SourceUnpackedness -> Rep SourceUnpackedness x # to :: Rep SourceUnpackedness x -> SourceUnpackedness #
Generic SrcLoc
Instance details Defined in GHC.Generics Associated Types type Rep SrcLoc :: Type -> Type # Methods from :: SrcLoc -> Rep SrcLoc x # to :: Rep SrcLoc x -> SrcLoc #
Generic GeneralCategory
Instance details Defined in GHC.Generics Associated Types type Rep GeneralCategory :: Type -> Type # Methods from :: GeneralCategory -> Rep GeneralCategory x # to :: Rep GeneralCategory x -> GeneralCategory #
Generic Ordering
Instance details Defined in GHC.Generics Associated Types type Rep Ordering :: Type -> Type # Methods from :: Ordering -> Rep Ordering x # to :: Rep Ordering x -> Ordering #
Generic ()
Instance details Defined in GHC.Generics Associated Types type Rep () :: Type -> Type # Methods from :: () -> Rep () x # to :: Rep () x -> () #
Generic Bool
Instance details Defined in GHC.Generics Associated Types type Rep Bool :: Type -> Type # Methods from :: Bool -> Rep Bool x # to :: Rep Bool x -> Bool #
Generic (ZipList a)
Instance details Defined in Control.Applicative Associated Types type Rep (ZipList a) :: Type -> Type # Methods from :: ZipList a -> Rep (ZipList a) x # to :: Rep (ZipList a) x -> ZipList a #
Generic (Identity a)
Instance details Defined in Data.Functor.Identity Associated Types type Rep (Identity a) :: Type -> Type # Methods from :: Identity a -> Rep (Identity a) x # to :: Rep (Identity a) x -> Identity a #
Generic (First a)
Instance details Defined in Data.Monoid Associated Types type Rep (First a) :: Type -> Type # Methods from :: First a -> Rep (First a) x # to :: Rep (First a) x -> First a #
Generic (Last a)
Instance details Defined in Data.Monoid Associated Types type Rep (Last a) :: Type -> Type # Methods from :: Last a -> Rep (Last a) x # to :: Rep (Last a) x -> Last a #
Generic (Down a)
Instance details Defined in GHC.Generics Associated Types type Rep (Down a) :: Type -> Type # Methods from :: Down a -> Rep (Down a) x # to :: Rep (Down a) x -> Down a #
Generic (First a)
Instance details Defined in Data.Semigroup Associated Types type Rep (First a) :: Type -> Type # Methods from :: First a -> Rep (First a) x # to :: Rep (First a) x -> First a #
Generic (Last a)
Instance details Defined in Data.Semigroup Associated Types type Rep (Last a) :: Type -> Type # Methods from :: Last a -> Rep (Last a) x # to :: Rep (Last a) x -> Last a #
Generic (Max a)
Instance details Defined in Data.Semigroup Associated Types type Rep (Max a) :: Type -> Type # Methods from :: Max a -> Rep (Max a) x # to :: Rep (Max a) x -> Max a #
Generic (Min a)
Instance details Defined in Data.Semigroup Associated Types type Rep (Min a) :: Type -> Type # Methods from :: Min a -> Rep (Min a) x # to :: Rep (Min a) x -> Min a #
Generic (WrappedMonoid m)
Instance details Defined in Data.Semigroup Associated Types type Rep (WrappedMonoid m) :: Type -> Type # Methods from :: WrappedMonoid m -> Rep (WrappedMonoid m) x # to :: Rep (WrappedMonoid m) x -> WrappedMonoid m #
Generic (Dual a)
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep (Dual a) :: Type -> Type # Methods from :: Dual a -> Rep (Dual a) x # to :: Rep (Dual a) x -> Dual a #
Generic (Endo a)
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep (Endo a) :: Type -> Type # Methods from :: Endo a -> Rep (Endo a) x # to :: Rep (Endo a) x -> Endo a #
Generic (Product a)
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep (Product a) :: Type -> Type # Methods from :: Product a -> Rep (Product a) x # to :: Rep (Product a) x -> Product a #
Generic (Sum a)
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep (Sum a) :: Type -> Type # Methods from :: Sum a -> Rep (Sum a) x # to :: Rep (Sum a) x -> Sum a #
Generic (Par1 p)
Instance details Defined in GHC.Generics Associated Types type Rep (Par1 p) :: Type -> Type # Methods from :: Par1 p -> Rep (Par1 p) x # to :: Rep (Par1 p) x -> Par1 p #
Generic (NonEmpty a)
Instance details Defined in GHC.Generics Associated Types type Rep (NonEmpty a) :: Type -> Type # Methods from :: NonEmpty a -> Rep (NonEmpty a) x # to :: Rep (NonEmpty a) x -> NonEmpty a #
Generic (Maybe a)
Instance details Defined in GHC.Generics Associated Types type Rep (Maybe a) :: Type -> Type # Methods from :: Maybe a -> Rep (Maybe a) x # to :: Rep (Maybe a) x -> Maybe a #
Generic (a)
Instance details Defined in GHC.Generics Associated Types type Rep (a) :: Type -> Type # Methods from :: (a) -> Rep (a) x # to :: Rep (a) x -> (a) #
Generic [a]
Instance details Defined in GHC.Generics Associated Types type Rep [a] :: Type -> Type # Methods from :: [a] -> Rep [a] x # to :: Rep [a] x -> [a] #
Generic (WrappedMonad m a)
Instance details Defined in Control.Applicative Associated Types type Rep (WrappedMonad m a) :: Type -> Type # Methods from :: WrappedMonad m a -> Rep (WrappedMonad m a) x # to :: Rep (WrappedMonad m a) x -> WrappedMonad m a #
Generic (Either a b)
Instance details Defined in GHC.Generics Associated Types type Rep (Either a b) :: Type -> Type # Methods from :: Either a b -> Rep (Either a b) x # to :: Rep (Either a b) x -> Either a b #
Generic (Proxy t)
Instance details Defined in GHC.Generics Associated Types type Rep (Proxy t) :: Type -> Type # Methods from :: Proxy t -> Rep (Proxy t) x # to :: Rep (Proxy t) x -> Proxy t #
Generic (Arg a b)
Instance details Defined in Data.Semigroup Associated Types type Rep (Arg a b) :: Type -> Type # Methods from :: Arg a b -> Rep (Arg a b) x # to :: Rep (Arg a b) x -> Arg a b #
Generic (U1 p)
Instance details Defined in GHC.Generics Associated Types type Rep (U1 p) :: Type -> Type # Methods from :: U1 p -> Rep (U1 p) x # to :: Rep (U1 p) x -> U1 p #
Generic (V1 p)
Instance details Defined in GHC.Generics Associated Types type Rep (V1 p) :: Type -> Type # Methods from :: V1 p -> Rep (V1 p) x # to :: Rep (V1 p) x -> V1 p #
Generic (a, b)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b) :: Type -> Type # Methods from :: (a, b) -> Rep (a, b) x # to :: Rep (a, b) x -> (a, b) #
Generic (WrappedArrow a b c)
Instance details Defined in Control.Applicative Associated Types type Rep (WrappedArrow a b c) :: Type -> Type # Methods from :: WrappedArrow a b c -> Rep (WrappedArrow a b c) x # to :: Rep (WrappedArrow a b c) x -> WrappedArrow a b c #
Generic (Ap f a)
Instance details Defined in Data.Monoid Associated Types type Rep (Ap f a) :: Type -> Type # Methods from :: Ap f a -> Rep (Ap f a) x # to :: Rep (Ap f a) x -> Ap f a #
Generic (Alt f a)
Instance details Defined in Data.Semigroup.Internal Associated Types type Rep (Alt f a) :: Type -> Type # Methods from :: Alt f a -> Rep (Alt f a) x # to :: Rep (Alt f a) x -> Alt f a #
Generic (Rec1 f p)
Instance details Defined in GHC.Generics Associated Types type Rep (Rec1 f p) :: Type -> Type # Methods from :: Rec1 f p -> Rep (Rec1 f p) x # to :: Rep (Rec1 f p) x -> Rec1 f p #
Generic (URec (Ptr ()) p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec (Ptr ()) p) :: Type -> Type # Methods from :: URec (Ptr ()) p -> Rep (URec (Ptr ()) p) x # to :: Rep (URec (Ptr ()) p) x -> URec (Ptr ()) p #
Generic (URec Char p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Char p) :: Type -> Type # Methods from :: URec Char p -> Rep (URec Char p) x # to :: Rep (URec Char p) x -> URec Char p #
Generic (URec Double p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Double p) :: Type -> Type # Methods from :: URec Double p -> Rep (URec Double p) x # to :: Rep (URec Double p) x -> URec Double p #
Generic (URec Float p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Float p) :: Type -> Type # Methods from :: URec Float p -> Rep (URec Float p) x # to :: Rep (URec Float p) x -> URec Float p #
Generic (URec Int p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Int p) :: Type -> Type # Methods from :: URec Int p -> Rep (URec Int p) x # to :: Rep (URec Int p) x -> URec Int p #
Generic (URec Word p)
Instance details Defined in GHC.Generics Associated Types type Rep (URec Word p) :: Type -> Type # Methods from :: URec Word p -> Rep (URec Word p) x # to :: Rep (URec Word p) x -> URec Word p #
Generic (a, b, c)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c) :: Type -> Type # Methods from :: (a, b, c) -> Rep (a, b, c) x # to :: Rep (a, b, c) x -> (a, b, c) #
Generic ((f :*: g) p)
Instance details Defined in GHC.Generics Associated Types type Rep ((f :: g) p) :: Type -> Type # Methods from :: (f :: g) p -> Rep ((f :: g) p) x # to :: Rep ((f :: g) p) x -> (f :*: g) p #
Generic ((f :+: g) p)
Instance details Defined in GHC.Generics Associated Types type Rep ((f :+: g) p) :: Type -> Type # Methods from :: (f :+: g) p -> Rep ((f :+: g) p) x # to :: Rep ((f :+: g) p) x -> (f :+: g) p #
Generic (K1 i c p)
Instance details Defined in GHC.Generics Associated Types type Rep (K1 i c p) :: Type -> Type # Methods from :: K1 i c p -> Rep (K1 i c p) x # to :: Rep (K1 i c p) x -> K1 i c p #
Generic (a, b, c, d)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d) :: Type -> Type # Methods from :: (a, b, c, d) -> Rep (a, b, c, d) x # to :: Rep (a, b, c, d) x -> (a, b, c, d) #
Generic ((f :.: g) p)
Instance details Defined in GHC.Generics Associated Types type Rep ((f :.: g) p) :: Type -> Type # Methods from :: (f :.: g) p -> Rep ((f :.: g) p) x # to :: Rep ((f :.: g) p) x -> (f :.: g) p #
Generic (M1 i c f p)
Instance details Defined in GHC.Generics Associated Types type Rep (M1 i c f p) :: Type -> Type # Methods from :: M1 i c f p -> Rep (M1 i c f p) x # to :: Rep (M1 i c f p) x -> M1 i c f p #
Generic (a, b, c, d, e)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e) :: Type -> Type # Methods from :: (a, b, c, d, e) -> Rep (a, b, c, d, e) x # to :: Rep (a, b, c, d, e) x -> (a, b, c, d, e) #
Generic (a, b, c, d, e, f)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f) :: Type -> Type # Methods from :: (a, b, c, d, e, f) -> Rep (a, b, c, d, e, f) x # to :: Rep (a, b, c, d, e, f) x -> (a, b, c, d, e, f) #
Generic (a, b, c, d, e, f, g)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g) -> Rep (a, b, c, d, e, f, g) x # to :: Rep (a, b, c, d, e, f, g) x -> (a, b, c, d, e, f, g) #
Generic (a, b, c, d, e, f, g, h)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h) -> Rep (a, b, c, d, e, f, g, h) x # to :: Rep (a, b, c, d, e, f, g, h) x -> (a, b, c, d, e, f, g, h) #
Generic (a, b, c, d, e, f, g, h, i)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i) -> Rep (a, b, c, d, e, f, g, h, i) x # to :: Rep (a, b, c, d, e, f, g, h, i) x -> (a, b, c, d, e, f, g, h, i) #
Generic (a, b, c, d, e, f, g, h, i, j)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j) -> Rep (a, b, c, d, e, f, g, h, i, j) x # to :: Rep (a, b, c, d, e, f, g, h, i, j) x -> (a, b, c, d, e, f, g, h, i, j) #
Generic (a, b, c, d, e, f, g, h, i, j, k)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j, k) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j, k) -> Rep (a, b, c, d, e, f, g, h, i, j, k) x # to :: Rep (a, b, c, d, e, f, g, h, i, j, k) x -> (a, b, c, d, e, f, g, h, i, j, k) #
Generic (a, b, c, d, e, f, g, h, i, j, k, l)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j, k, l) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Rep (a, b, c, d, e, f, g, h, i, j, k, l) x # to :: Rep (a, b, c, d, e, f, g, h, i, j, k, l) x -> (a, b, c, d, e, f, g, h, i, j, k, l) #
Generic (a, b, c, d, e, f, g, h, i, j, k, l, m)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j, k, l, m) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Rep (a, b, c, d, e, f, g, h, i, j, k, l, m) x # to :: Rep (a, b, c, d, e, f, g, h, i, j, k, l, m) x -> (a, b, c, d, e, f, g, h, i, j, k, l, m) #
Generic (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n) x # to :: Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n) x -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #
Generic (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Instance details Defined in GHC.Generics Associated Types type Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) :: Type -> Type # Methods from :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) x # to :: Rep (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) x -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

class PartialSemigroup a where Source #

A PartialSemigroup is like a Semigroup, but with an operator returning Maybe a rather than a.

For comparison:

(<>)  :: Semigroup a        => a -> a -> a
(<>?) :: PartialSemigroup a => a -> a -> Maybe a

The associativity axiom for partial semigroups

For all x, y, z:

If x <>? y = Just xy and y <>? z = Just yz, then
- x <>? yz = xy <>? z.

Relationship to the semigroup associativity axiom

The partial semigroup associativity axiom is a natural adaptation of the semigroup associativity axiom

x <> (y <> z) = (x <> y) <> z

with a slight modification to accommodate situations where <> is undefined. We may gain some insight into the connection between Semigroup and PartialSemigroup by rephrasing the partial semigroup associativity in terms of a partial <> operator thusly:

For all x, y, z:

If x <> y and y <> z are both defined, then
- x <> (y <> z) is defined if and only if (x <> y) <> z is defined, and
- if these things are all defined, then the axiom for total semigroups x <> (y <> z) = (x <> y) <> z must hold.

Methods

(<>?) :: a -> a -> Maybe a infixr 6 Source #

Instances

Instances details

PartialSemigroup () Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: () -> () -> Maybe () Source #
PartialSemigroup a => PartialSemigroup (ZipList a) Source #	`partialZip`
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: ZipList a -> ZipList a -> Maybe (ZipList a) Source #
PartialSemigroup a => PartialSemigroup (Identity a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: Identity a -> Identity a -> Maybe (Identity a) Source #
Num a => PartialSemigroup (Product a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: Product a -> Product a -> Maybe (Product a) Source #
Num a => PartialSemigroup (Sum a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: Sum a -> Sum a -> Maybe (Sum a) Source #
PartialSemigroup (AtMostOne a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: AtMostOne a -> AtMostOne a -> Maybe (AtMostOne a) Source #
PartialSemigroup (One a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: One a -> One a -> Maybe (One a) Source #
Semigroup a => PartialSemigroup (Total a) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: Total a -> Total a -> Maybe (Total a) Source #
PartialSemigroup [a] Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: [a] -> [a] -> Maybe [a] Source #
(PartialSemigroup a, PartialSemigroup b) => PartialSemigroup (Either a b) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: Either a b -> Either a b -> Maybe (Either a b) Source #
PartialSemigroup a => PartialSemigroup (AppendLeft a b) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: AppendLeft a b -> AppendLeft a b -> Maybe (AppendLeft a b) Source #
PartialSemigroup b => PartialSemigroup (AppendRight a b) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: AppendRight a b -> AppendRight a b -> Maybe (AppendRight a b) Source #
(PartialSemigroup a, PartialSemigroup b) => PartialSemigroup (a, b) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: (a, b) -> (a, b) -> Maybe (a, b) Source #
(PartialSemigroup a, PartialSemigroup b, PartialSemigroup c) => PartialSemigroup (a, b, c) Source #
Instance details Defined in Data.PartialSemigroup Methods (<>?) :: (a, b, c) -> (a, b, c) -> Maybe (a, b, c) Source #