Modulepersistent-2.18.1.0Haskell2010

Database.Persist.Quasi.Internal.TypeParser

2 types
3 values

Packagepersistent-2.18.1.0
Exports5
LanguageHaskell2010
LicenceMIT
SourceTypeParser.hs

datadata TypeExpr

A parsed type expression.

Constructors

TypeApplication TypeExpr [TypeExpr]
TypeConstructorExpr TypeConstructor
TypeLitString String
TypeLitInt String
TypeLitPromotedConstructor TypeConstructor

Instances2Eq, Show

Eq TypeExprDefined in persistent-2.18.1.0 · Database.Persist.Quasi.Internal.TypeParser
Show TypeExprDefined in persistent-2.18.1.0 · Database.Persist.Quasi.Internal.TypeParser

datadata TypeConstructor

A parsed type constructor.

Constructors

ListConstructor
TypeConstructor String

Instances2Eq, Show

Eq TypeConstructorDefined in persistent-2.18.1.0 · Database.Persist.Quasi.Internal.TypeParser
Show TypeConstructorDefined in persistent-2.18.1.0 · Database.Persist.Quasi.Internal.TypeParser

valuetypeExpr :: MonadParsec e String m => m TypeExpr

Parses a Persistent-style type expression. Persistent's type expressions are largely similar to Haskell's, but with a few differences:

Syntactic sugar is not currently supported for constructing types other than List.
Only certain typelevel literals are supported: Strings, Ints, and promoted type constructors.
Because they must be parsed as part of an entity field definition, top-level applications of non-nullary type constructors (except for the sugary List constructor) must be parenthesized.

VALID: Int VALID: [Maybe Int] VALID: (Maybe Int) INVALID: Maybe Int

valueinnerTypeExpr :: MonadParsec e String m => m TypeExpr

Parses a type expression in non-top-level contexts, where an unparenthesized type constructor application is acceptable.

valuetypeExprContent :: TypeExpr -> Text

Given a TypeExpr, renders it back to a String in a canonical form that looks normal to humans and is re-parseable when making an UnboundEntityDef that uses it.