Safe Haskell	Safe-Inferred
Language	GHC2021

Generic.Data.Function.Traverse

Description

traverse for generic data types.

TODO This is harder to conceptualize than generic foldMap. No nice clean explanation yet.

This function can provide generic support for simple parser-esque types.

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)
genericTraverseNonSum :: forall {k} (tag :: k) a. (Generic a, Functor (GenericTraverseF tag), GTraverseNonSum tag (Rep a)) => GenericTraverseF tag a
class GTraverseNonSum tag gf
genericTraverseSum :: forall tag sumtag a pt. (Generic a, Functor (GenericTraverseF tag), GTraverseSum tag sumtag (Rep a)) => ParseCstrTo sumtag pt -> (String -> GenericTraverseF tag pt) -> (forall x. String -> GenericTraverseF tag x) -> (pt -> pt -> Bool) -> GenericTraverseF tag a
class GTraverseSum tag sumtag gf
genericTraverseSumRaw :: forall tag a pt. (Generic a, Functor (GenericTraverseF tag), GTraverseSum tag Raw (Rep a)) => (String -> pt) -> (String -> GenericTraverseF tag pt) -> (forall x. String -> GenericTraverseF tag x) -> (pt -> pt -> Bool) -> GenericTraverseF tag a

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 #

genericTraverseNonSum :: forall {k} (tag :: k) a. (Generic a, Functor (GenericTraverseF tag), GTraverseNonSum tag (Rep a)) => GenericTraverseF tag a Source #

Generic traverse over a term of non-sum data type f a, where f is set by the tag you pass.

class GTraverseNonSum tag gf Source #

Minimal complete definition

gTraverseNonSum

Instances

Instances details

(Functor (GenericTraverseF tag), GTraverseNonSumD tag dtName gf) => GTraverseNonSum (tag :: k1) (D1 ('MetaData dtName _md2 _md3 _md4) gf :: k2 -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.NonSum Methods gTraverseNonSum :: forall (p :: k10). GenericTraverseF tag (D1 ('MetaData dtName _md2 _md3 _md4) gf p) Source #

genericTraverseSum :: forall tag sumtag a pt. (Generic a, Functor (GenericTraverseF tag), GTraverseSum tag sumtag (Rep a)) => ParseCstrTo sumtag pt -> (String -> GenericTraverseF tag pt) -> (forall x. String -> GenericTraverseF tag x) -> (pt -> pt -> Bool) -> GenericTraverseF tag a Source #

class GTraverseSum tag sumtag gf Source #

Minimal complete definition

gTraverseSum

Instances

Instances details

GenericTraverse tag => GTraverseSum (tag :: k1) (sumtag :: k2) (V1 :: k3 -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.Sum Methods gTraverseSum :: forall pt (p :: k20). ParseCstrTo sumtag pt -> (String -> GenericTraverseF tag pt) -> (forall a. String -> GenericTraverseF tag a) -> (pt -> pt -> Bool) -> GenericTraverseF tag (V1 p) Source #
(f ~ GenericTraverseF tag, Alternative f, Monad f, KnownSymbol dtName, GTraverseCSum tag sumtag dtName gf) => GTraverseSum (tag :: k1) (sumtag :: k2) (D1 ('MetaData dtName _md2 _md3 _md4) gf :: k3 -> Type) Source #
Instance details Defined in Generic.Data.Function.Traverse.Sum Methods gTraverseSum :: forall pt (p :: k20). ParseCstrTo sumtag pt -> (String -> GenericTraverseF tag pt) -> (forall a. String -> GenericTraverseF tag a) -> (pt -> pt -> Bool) -> GenericTraverseF tag (D1 ('MetaData dtName _md2 _md3 _md4) gf p) Source #

genericTraverseSumRaw :: forall tag a pt. (Generic a, Functor (GenericTraverseF tag), GTraverseSum tag Raw (Rep a)) => (String -> pt) -> (String -> GenericTraverseF tag pt) -> (forall x. String -> GenericTraverseF tag x) -> (pt -> pt -> Bool) -> GenericTraverseF tag a Source #