Safe Haskell	Safe-Inferred
Language	GHC2021

Generic.Data.Function.Traverse.Constructor

Synopsis

class GenericTraverse tag where
- type GenericTraverseF tag :: Type -> Type
- type GenericTraverseC tag a :: Constraint
- genericTraverseAction :: GenericTraverseC tag a => String -> String -> Maybe String -> Natural -> GenericTraverseF tag a
- genericTraverseV1 :: GenericTraverseF tag (V1 p)
type ENoEmpty tag = ('Text "Attempted to derive generic traverse for the void data type" :$$: 'Text "To override, implement genericTraverseV1 on:") :$$: (('Text "instance GenericTraverse (" :<>: 'ShowType tag) :<>: 'Text ")")
class GTraverseC tag (cd :: Symbol) (cc :: Symbol) (si :: Natural) gf where
- gTraverseC :: GenericTraverseF tag (gf p)
type family ProdArity (f :: Type -> Type) :: Natural where ...
class ReifyMaybeSymbol (mstr :: Maybe Symbol) where
- reifyMaybeSymbol :: Maybe String

Documentation

class GenericTraverse tag where Source #

Implementation enumeration type class for generic traverse.

The type variable is uninstantiated, used purely as a tag. Good types include the type class used inside (providing you define the type class/it's not an orphan instance), or a custom void data type. See the binrep library on Hackage for an example.

Minimal complete definition

genericTraverseAction

Associated Types

type GenericTraverseF tag :: Type -> Type Source #

The target Applicative to traverse to.

type GenericTraverseC tag a :: Constraint Source #

The type class providing the action in traverse for permitted types.

Methods

genericTraverseAction Source #

Arguments

:: GenericTraverseC tag a
=> String	data type name
-> String	constructor name
-> Maybe String	record name (if present)
-> Natural	field index
-> GenericTraverseF tag a

The action in traverse (first argument).

We include data type metadata because this function is useful for monadic parsers, which can record it in error messages. (We don't do it for foldMap because it's pure.)

genericTraverseV1 :: GenericTraverseF tag (V1 p) Source #

Action to run when trying to parse a V1 (void data type).

Defaults to error, but you may wrap it in your functor if it pleases.

Instances

Instances details

GenericTraverse (EmptyRec0 f :: Type) Source #	`traverse` over types where all fields are replaced with the functor's `empty`. Note that one may write a valid instance using a `Monoid` on `a`s instead. I don't think you should. But I can't explain why.
Instance details Defined in Generic.Data.Function.Traverse.Constructor Associated Types type GenericTraverseF (EmptyRec0 f) :: Type -> Type Source # type GenericTraverseC (EmptyRec0 f) a Source # Methods genericTraverseAction :: GenericTraverseC (EmptyRec0 f) a => String -> String -> Maybe String -> Natural -> GenericTraverseF (EmptyRec0 f) a Source # genericTraverseV1 :: forall {k1} (p :: k1). GenericTraverseF (EmptyRec0 f) (V1 p) Source #
GenericTraverse (NoRec0 f :: Type) Source #	`traverse` over types with no fields in any constructor.
Instance details Defined in Generic.Data.Function.Traverse.Constructor Associated Types type GenericTraverseF (NoRec0 f) :: Type -> Type Source # type GenericTraverseC (NoRec0 f) a Source # Methods genericTraverseAction :: GenericTraverseC (NoRec0 f) a => String -> String -> Maybe String -> Natural -> GenericTraverseF (NoRec0 f) a Source # genericTraverseV1 :: forall {k1} (p :: k1). GenericTraverseF (NoRec0 f) (V1 p) Source #

type ENoEmpty tag = ('Text "Attempted to derive generic traverse for the void data type" :$$: 'Text "To override, implement genericTraverseV1 on:") :$$: (('Text "instance GenericTraverse (" :<>: 'ShowType tag) :<>: 'Text ")") Source #

class GTraverseC tag (cd :: Symbol) (cc :: Symbol) (si :: Natural) gf where Source #

Methods

gTraverseC :: GenericTraverseF tag (gf p) Source #

Instances

Instances details

Applicative (GenericTraverseF tag) => GTraverseC (tag :: k1) cd cc 0 (U1 :: k2 -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.Constructor Methods gTraverseC :: forall (p :: k10). GenericTraverseF tag (U1 p) Source #
(Applicative (GenericTraverseF tag), GTraverseC tag cd cc si l, GTraverseC tag cd cc (si + ProdArity r) r) => GTraverseC (tag :: k) cd cc si (l :*: r :: Type -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.Constructor Methods gTraverseC :: forall (p :: k1). GenericTraverseF tag ((l :*: r) p) Source #
(GenericTraverse tag, GenericTraverseC tag a, Functor (GenericTraverseF tag), KnownNat si, ReifyMaybeSymbol mSelName, KnownSymbol cc, KnownSymbol cd) => GTraverseC (tag :: k1) cd cc si (S1 ('MetaSel mSelName _ms2 _ms3 _ms4) (Rec0 a) :: k2 -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.Constructor Methods gTraverseC :: forall (p :: k10). GenericTraverseF tag (S1 ('MetaSel mSelName _ms2 _ms3 _ms4) (Rec0 a) p) Source #

type family ProdArity (f :: Type -> Type) :: Natural where ... Source #

Equations

ProdArity (S1 c f) = 1
ProdArity (l :*: r) = ProdArity l + ProdArity r

class ReifyMaybeSymbol (mstr :: Maybe Symbol) where Source #

Methods

reifyMaybeSymbol :: Maybe String Source #

Instances

Instances details

ReifyMaybeSymbol ('Nothing :: Maybe Symbol) Source #
Instance details Defined in Generic.Data.Function.Traverse.Constructor Methods reifyMaybeSymbol :: Maybe String Source #
KnownSymbol str => ReifyMaybeSymbol ('Just str) Source #
Instance details Defined in Generic.Data.Function.Traverse.Constructor Methods reifyMaybeSymbol :: Maybe String Source #