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GHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05

Modulelinear-generics-0.2.3Haskell2010

Generics.Linear

Multiplicity polymorphic versions of GHC.Generics.Generic and GHC.Generics.Generic1. Generic is otherwise identical to the standard version. Generic1 is similar, but with modifications that make it more efficient, as well as supporting linearity.

This module re-exports everything in GHC.Generics except Generic, Generic1, G.Rec1, and :.:. The Generic1 representations here don't need G.Rec1. We expose our own, identical, :.:. This allows users to instantiate their Generic1-based generic-deriving classes so they can be used with both GHC.Generics and this package.

In addition to the usual generic types, we export one called MP1 for use with nonlinear and multiplicity polymorphic fields. Nonlinear generic-deriving classes should almost always handle MP1 without restriction. Some linear generic-deriving classes will need to constrain its m parameter to be 'One.

  • 32 types
  • 5 classes
  • 8 values
datadata Meta
#

Datatype to represent metadata associated with a datatype (MetaData), constructor (MetaCons), or field selector (MetaSel).

  • In MetaData n m p nt, n is the datatype's name, m is the module in which the datatype is defined, p is the package in which the datatype is defined, and nt is 'True if the datatype is a newtype.

  • In MetaCons n f s, n is the constructor's name, f is its fixity, and s is 'True if the constructor contains record selectors.

  • In MetaSel mn su ss ds, if the field uses record syntax, then mn is Just the record name. Otherwise, mn is Nothing. su and ss are the field's unpackedness and strictness annotations, and ds is the strictness that GHC infers for the field.

Constructors

Instances3Constructor, Datatype, Selector
classclass Datatype (d :: k) where
#

Class for datatypes that represent datatypes

Methods

  • datatypeName :: t d f a -> [Char]

    The name of the datatype (unqualified)

  • moduleName :: t d f a -> [Char]

    The fully-qualified name of the module where the type is declared

  • packageName :: t d f a -> [Char]

    The package name of the module where the type is declared

  • isNewtype :: t d f a -> Bool

    Marks if the datatype is actually a newtype

Instances1Datatype
data familydata family URec a (p :: k)
#

Constants of unlifted kinds

Instances90GNFData, Generic1, Foldable, Traversable, Functor, Eq, …
newtypenewtype M1 i (c :: Meta) (f :: k -> Type) (p :: k)
#

Meta-information (constructor names, etc.)

Constructors

Instances27GNFData, Generic1, Monad, Functor, MonadFix, Applicative, …
newtypenewtype K1 i c (p :: k)
#

Constants, additional parameters and recursion of kind *

Constructors

Instances24GNFData, Generic1, Bifoldable, Bifunctor, Bitraversable, Functor, …
newtypenewtype Par1 p
#

Used for marking occurrences of the parameter

Constructors

Instances24Monad, Functor, MonadFix, Applicative, Foldable, Traversable, …
newtypenewtype (:.:) (f :: k2 -> Type) (g :: k1 -> k2) (x :: k1)
#

The composition operator for types. We use our own here because for many classes, it's possible to share generic deriving classes between GHC.Generics and Generics.Linear by just instantiating them for both composition operators (and MP1).

Constructors

Instances25Generic1, Functor, Applicative, Foldable, Traversable, Alternative, …
classclass Generic a where
#

Generic is exactly the same as GHC.Generics.Generic except that to and from are multiplicity polymorphic. This means they will work equally well in traditional Haskell code and in linearly typed code.

Associated types

Methods

Instances139Generic, …
  • Generic ForeignSrcLangDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ExtensionDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic VoidDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic AllDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic AnyDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic VersionDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic AssociativityDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic DecidedStrictnessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic FixityDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic SourceStrictnessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic SourceUnpackednessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic ExitCodeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic BoolDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic CharDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic DoubleDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic FloatDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic IntDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic OrderingDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic WordDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic AnnLookupDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic AnnTargetDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic BangDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic BodyDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic CallconvDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ClauseDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ConDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic DecDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic DecidedStrictnessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ExpDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic FamilyResultSigDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic FixityDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic FixityDirectionDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ForeignDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic FunDepDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic GuardDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic InfoDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic InjectivityAnnDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic InlineDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic LitDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic LocDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic MatchDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ModuleDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ModuleInfoDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic NameDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic NameFlavourDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic NameSpaceDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic OccNameDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PatDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PatSynArgsDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PatSynDirDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PhasesDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PkgNameDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic PragmaDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic RangeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic RoleDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic RuleBndrDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic RuleMatchDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic SafetyDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic SourceStrictnessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic SourceUnpackednessDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic SpecificityDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic StmtDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic TyLitDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic TySynEqnDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic TypeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic TypeFamilyHeadDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic ()Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic a => Generic (GHCGenerically a)Defined in linear-generics-0.2.3 · Generics.Linear.Unsafe.ViaGHCGenerics
  • Generic (Complex a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (First a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Last a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Max a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Min a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (WrappedMonoid m)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Digit a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (Elem a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (FingerTree a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (Node a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (ViewL a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (ViewR a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (Tree a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic (NonEmpty a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Identity a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (First a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Last a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Down a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Dual a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Endo a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Product a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Sum a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (ZipList a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Par1 p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Maybe a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Ptr a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (TyVarBndr flag)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic (a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic [a]Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (WrappedMonad m a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Arg a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Either a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Proxy t)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (U1 p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (V1 p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (WrappedArrow a b c)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Kleisli m a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Const a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Ap f a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Alt f a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Rec1 f p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec Char p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec Double p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec Float p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec Int p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec Word p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (URec (Ptr ()) p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Code m a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic (a, b, c)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Product f g a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (Sum f g a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (K1 i c p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (MP1 m f a)Defined in linear-generics-0.2.3 · Generics.Linear.Class
  • Generic ((:*:) f g p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic ((:+:) f g p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (M1 i c f p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic ((:.:) f g p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic ((:.:) f g x)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Linear_generics · orphan
  • Generic (a, b, c, d, e)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j, k)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j, k, l)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j, k, l, m)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j, k, l, m, n)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
classclass Generic1 (f :: k -> Type) where
#

Generic1 is similar to GHC.Generics.Generic1, but has a few differences.

Multiplicity polymorphism

As with Generic, the to1 and from1 methods are multiplicity polymorphic.

Differences in Rep1 representation

Rec1 is not used

Given a type like

newtype Foo a = Foo (Maybe a)

where a single type constructor (here Maybe) is applied to the parameter, GHC.Generics represents the field as Rec1 Maybe. We instead represent it using Par1 :.: Maybe. It is expected that very few real-life uses of GHC.Generics will break as a result, and this simplification means that users don't have to write Rec1 instances for their generic-deriving classes.

Compositions associate in the opposite order

Given a type like

newtype Bar a = Bar (Maybe [Either e a])

where multiple type constructors are layered around the parameter, "GHC.Generics@ represents the field as

Maybe :.: ([] :.: Rec1 (Either e))

We instead represent it as

((Par1 :.: Maybe) :.: []) :.: Either e

Doing it this way prevents to1 and from1 from having to fmap newtype constructors through the composed types, which can be a considerable performance improvement and enables multiplicity polymorphism.

In most cases, modifying generic-deriving classes to accommodate this change is simple: just swap which side of the composition is treated as a generic representation and which as a base type. In a few cases, more restructuring will be needed, which will require using different generic-deriving classes than for GHC.Generics.

Difference in specificity

Users of type application will need to be aware that the kind parameter for Generic1 is marked as inferred, whereas for GHC.Generics.Generic1 it is marked as specified. So you should use, for example, to1 @Maybe rather than to1 @_ @Maybe.

Associated types

Methods

Instances71Generic1, …
  • Generic1 ComplexDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 FirstDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 LastDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 MaxDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 MinDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 WrappedMonoidDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 DigitDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 ElemDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 FingerTreeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 NodeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 ViewLDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 ViewRDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 TreeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Containers · orphan
  • Generic1 NonEmptyDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 IdentityDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 FirstDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 LastDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 DownDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 DualDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 ProductDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 SumDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 ZipListDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 Par1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 MaybeDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 SoloDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 TyVarBndrDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
  • Generic1 []Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 ProxyDefined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 U1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 V1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (WrappedMonad m)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Arg a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Either a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple2 a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (WrappedArrow a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Kleisli m a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Const a)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Ap f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Alt f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Rec1 f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec Char)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec Double)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec Float)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec Int)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec Word)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (URec (Ptr ()))Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple3 a b)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • (forall (a :: k). Generic (f a), CheckValid f) => Generic1 (GHCGenerically1 f)Defined in linear-generics-0.2.3 · Generics.Linear.Unsafe.ViaGHCGenerics
  • Generic1 (Product f g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Sum f g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (K1 i c)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple4 a b c)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (MP1 m f)Defined in linear-generics-0.2.3 · Generics.Linear.Class
  • Generic1 (f :*: g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (f :+: g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Compose f g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (M1 i c f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple5 a b c d)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (f :.: g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (f :.: g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Linear_generics · orphan
  • Generic1 (Tuple6 a b c d e)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple7 a b c d e f)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple8 a b c d e f g)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple9 a b c d e f g h)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple10 a b c d e f g h i)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple11 a b c d e f g h i j)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple12 a b c d e f g h i j k)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple13 a b c d e f g h i j k l)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple14 a b c d e f g h i j k l m)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Tuple15 a b c d e f g h i j k l m n)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Generic1 (Code m)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Template_haskell · orphan
datadata MP1 (a :: Multiplicity) (b :: k -> Type) (c :: k) where
#

Types with nonlinear or multiplicity-polymorphic fields should use MP1 under S1. Unfortunately, Template Haskell (and GHC Generics) currently lack any support for such types, so their instances must currently be written entirely manually. We may add some functions to ease the pain at some point.

Generic-deriving classes that do not involve linear types should treat MP1 m much as they treat M1: dig through it to get to the meat. Unfortunately, some futzing about may be necessary to convince the type checker that multiplicities work out.

Generic-deriving classes that use linear types may have to treat MP1 m specially. In particular, they may need to constrain m to be 'One or 'Many, or to match some other type variable.

Constructors

Instances27Generic1, Monad, Functor, Applicative, Foldable, Traversable, …
valueunMP1 :: MP1 m f a %n -> f a
#

Extract the value from an MP1.

datadata D
#

Tag for M1: datatype

datadata S
#

Tag for M1: record selector

familytype family Rep a :: Type -> Type
#
Instances139Rep, …
familytype family Rep1 (f :: k -> Type) :: k -> Type
#
Instances71Rep1, …
classclass Constructor (c :: k) where
#

Class for datatypes that represent data constructors

Methods

Instances1Constructor
typetype D1 = M1 D
#

Type synonym for encoding meta-information for datatypes

typetype C1 = M1 C
#

Type synonym for encoding meta-information for constructors

datadata FixityI
#

This variant of Fixity appears at the type level.

Constructors

Instances5SingKind, SingI, DemoteRep, Sing
  • SingKind FixityIDefined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • SingI 'PrefixIDefined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • (SingI a, KnownNat n) => SingI ('InfixI a n)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • type DemoteRep FixityI = FixityDefined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • data SingDefined in ghc-internal-9.1003.0 · GHC.Internal.Generics
typetype S1 = M1 S
#

Type synonym for encoding meta-information for record selectors

datadata SourceUnpackedness
#

The unpackedness of a field as the user wrote it in the source code. For example, in the following data type:

data E = ExampleConstructor     Int
           {-# NOUNPACK #-} Int
           {-#   UNPACK #-} Int

The fields of ExampleConstructor have NoSourceUnpackedness, SourceNoUnpack, and SourceUnpack, respectively.

NoSourceUnpackednessSourceNoUnpackSourceUnpack
Instances18Bounded, Enum, Eq, Data, Ord, Read, …
datadata SourceStrictness
#

The strictness of a field as the user wrote it in the source code. For example, in the following data type:

data E = ExampleConstructor Int ~Int !Int

The fields of ExampleConstructor have NoSourceStrictness, SourceLazy, and SourceStrict, respectively.

NoSourceStrictnessSourceLazySourceStrict
Instances18Bounded, Enum, Eq, Data, Ord, Read, …
datadata DecidedStrictness
#

The strictness that GHC infers for a field during compilation. Whereas there are nine different combinations of SourceUnpackedness and SourceStrictness, the strictness that GHC decides will ultimately be one of lazy, strict, or unpacked. What GHC decides is affected both by what the user writes in the source code and by GHC flags. As an example, consider this data type:

data E = ExampleConstructor {-# UNPACK #-} !Int !Int Int
DecidedLazyDecidedStrictDecidedUnpack
Instances18Bounded, Enum, Eq, Data, Ord, Read, …
typetype Rec0 = K1 R
#

Type synonym for encoding recursion (of kind Type)

classclass Selector (s :: k) where
#

Class for datatypes that represent records

Methods

Instances1Selector
  • (SingI mn, SingI su, SingI ss, SingI ds) => Selector ('MetaSel mn su ss ds)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
datadata Associativity
#

Datatype to represent the associativity of a constructor

LeftAssociativeRightAssociativeNotAssociative
Instances18Bounded, Enum, Eq, Data, Ord, Read, …
datadata C
#

Tag for M1: constructor

datadata R
#

Tag for K1: recursion (of kind Type)

datadata (:*:) (f :: k -> Type) (g :: k -> Type) (p :: k)
#

Products: encode multiple arguments to constructors

Constructors

  • f p :*: g pinfixr 6
Instances27GNFData, Generic1, Monad, Functor, MonadFix, Applicative, …
datadata (:+:) (f :: k -> Type) (g :: k -> Type) (p :: k)
#

Sums: encode choice between constructors

Constructors

Instances19GNFData, Generic1, Functor, Foldable, Traversable, Foldable1, …
datadata U1 (p :: k)
#

Unit: used for constructors without arguments

U1
Instances25GNFData, Generic1, Monad, Functor, Applicative, Foldable, …
  • Generic1 U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • GNFData arity U1Defined in deepseq-1.5.0.0 · Control.DeepSeq
  • Generic1 U1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Monad U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Functor U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Applicative U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Foldable U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Foldable
  • Traversable U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Traversable
  • Alternative U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • MonadPlus U1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • MonadZip U1Defined in base-4.20.2.0 · Control.Monad.Zip
  • Contravariant U1Defined in base-4.20.2.0 · Data.Functor.Contravariant
  • Eq (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Data p => Data (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Data
  • Ord (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Read (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Show (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Generic (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Semigroup (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Monoid (U1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Generic (U1 p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • type Rep (U1 p) = D1 ('MetaData "U1" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "U1" 'PrefixI 'False) U1)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • type Rep1 U1 = D1 ('MetaData "U1" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "U1" 'PrefixI 'False) U1)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • type Rep (U1 p) = D1 ('MetaData "U1" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "U1" 'PrefixI 'False) U1)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • type Rep1 U1 = D1 ('MetaData "U1" "GHC.Internal.Generics" "ghc-internal" 'False) (C1 ('MetaCons "U1" 'PrefixI 'False) U1)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
datadata V1 (p :: k)
#

Void: used for datatypes without constructors

Instances20GNFData, Generic1, Functor, Foldable, Traversable, Foldable1, …
  • Generic1 V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • GNFData arity V1Defined in deepseq-1.5.0.0 · Control.DeepSeq
  • Generic1 V1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • Functor V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Foldable V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Foldable
  • Traversable V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Traversable
  • Foldable1 V1Defined in base-4.20.2.0 · Data.Foldable1
  • Contravariant V1Defined in base-4.20.2.0 · Data.Functor.Contravariant
  • Eq (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Data p => Data (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Data.Data
  • Ord (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Read (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Show (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Generic (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Semigroup (V1 p)Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • Generic (V1 p)Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • type Rep (V1 p) = D1 ('MetaData "V1" "GHC.Internal.Generics" "ghc-internal" 'False) V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • type Rep1 V1 = D1 ('MetaData "V1" "GHC.Internal.Generics" "ghc-internal" 'False) V1Defined in ghc-internal-9.1003.0 · GHC.Internal.Generics
  • type Rep (V1 p) = D1 ('MetaData "V1" "GHC.Internal.Generics" "ghc-internal" 'False) V1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
  • type Rep1 V1 = D1 ('MetaData "V1" "GHC.Internal.Generics" "ghc-internal" 'False) V1Defined in linear-generics-0.2.3 · Generics.Linear.Instances.Base · orphan
newtypenewtype Generically1 (f :: k -> Type) (a :: k) where
#

A type whose instances are defined generically, using the Generic1 representation. Generically1 is a higher-kinded version of Generically that uses Generic.

Generic instances can be derived for type constructors via Generically1 F using -XDerivingVia.

{-# LANGUAGE DeriveGeneric      #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE DerivingVia        #-}

import GHC.Generics (Generic)

data V4 a = V4 a a a a
  deriving stock (Functor, Generic1)

  deriving Applicative
  via Generically1 V4

This corresponds to Applicative instances defined by pointwise lifting:

instance Applicative V4 where
  pure :: a -> V4 a
  pure a = V4 a a a a

  liftA2 :: (a -> b -> c) -> (V4 a -> V4 b -> V4 c)
  liftA2 (·) (V4 a1 b1 c1 d1) (V4 a2 b2 c2 d2) =
    V4 (a1 · a2) (b1 · b2) (c1 · c2) (d1 · d2)

Historically this required modifying the type class to include generic method definitions (-XDefaultSignatures) and deriving it with the anyclass strategy (-XDeriveAnyClass). Having a /via type/ like Generically1 decouples the instance from the type class.

Constructors

Instances7Functor, Applicative, Alternative, Eq1, Ord1, Eq, …
datadata Fixity
#

Datatype to represent the fixity of a constructor. An infix | declaration directly corresponds to an application of Infix.

Constructors

Instances9Eq, Data, Ord, Read, Show, Generic, …
newtypenewtype Generically a
#

A datatype whose instances are defined generically, using the Generic representation. Generically1 is a higher-kinded version of Generically that uses Generic1.

Generic instances can be derived via Generically A using -XDerivingVia.

{-# LANGUAGE DeriveGeneric      #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE DerivingVia        #-}

import GHC.Generics (Generic)

data V4 a = V4 a a a a
  deriving stock Generic

  deriving (Semigroup, Monoid)
  via Generically (V4 a)

This corresponds to Semigroup and Monoid instances defined by pointwise lifting:

instance Semigroup a => Semigroup (V4 a) where
  (<>) :: V4 a -> V4 a -> V4 a
  V4 a1 b1 c1 d1 <> V4 a2 b2 c2 d2 =
    V4 (a1 <> a2) (b1 <> b2) (c1 <> c2) (d1 <> d2)

instance Monoid a => Monoid (V4 a) where
  mempty :: V4 a
  mempty = V4 mempty mempty mempty mempty

Historically this required modifying the type class to include generic method definitions (-XDefaultSignatures) and deriving it with the anyclass strategy (-XDeriveAnyClass). Having a /via type/ like Generically decouples the instance from the type class.

Constructors

Instances2Semigroup, Monoid