| Copyright | Gautier DI FOLCO |
|---|---|
| License | ISC |
| Maintainer | Gautier DI FOLCO <gautier.difolco@gmail.com> |
| Stability | Unstable |
| Portability | not portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Data.Records.Yarl.LinkedList
Description
Provide a simple record library working with HasField
Example:
import Data.Records.Yarl.LinkedList type Person = Record '[Field "name" String, Field "age" Int] marvin :: Person marvin = Field "marvin" :> Field 42 :> RNil desc :: Person -> String desc p = "My name is " <> p.name <> " and I'm " <> show p.age
Synopsis
- data Record :: [Type] -> Type where
- newtype Field (name :: Symbol) a = Field {
- fieldValue :: a
- type family HasNotField (target :: Symbol) (names :: [Type]) :: Constraint where ...
- class HasField (x :: k) r a | x r -> a where
- getField :: r -> a
Documentation
data Record :: [Type] -> Type where Source #
Full extensible record
Constructors
| RNil :: Record '[] | |
| (:>) :: HasNotField fieldName fields => Field fieldName a -> Record fields -> Record (Field fieldName a ': fields) infixr 5 |
type family HasNotField (target :: Symbol) (names :: [Type]) :: Constraint where ... Source #
Watch for field name duplication
Equations
| HasNotField x '[] = () | |
| HasNotField x (Field x v ': ys) = TypeError ('Text "Field already declared: " :<>: 'ShowType x) | |
| HasNotField x (Field y v ': ys) = HasNotField x ys |
class HasField (x :: k) r a | x r -> a where #
Constraint representing the fact that the field x belongs to
the record type r and has field type a. This will be solved
automatically, but manual instances may be provided as well.