ref: 44a57dbfc137cb6e223b4150a974709e89f603fa
dir: /lib/Data/Records.hs/
module Data.Records(
module Data.Proxy,
HasField(..),
SetField(..),
hasField,
composeSet,
) where
import Prelude() -- do not import Prelude
import Primitives
import Data.Function
import Data.Proxy
type Get r a = r -> a
type Set r a = r -> a -> r
type GetSet r a = r -> (a, a -> r)
type HasField :: forall (k::Kind) . k -> Type -> Type -> Constraint
class HasField x r a | x r -> a where
getField :: Proxy x -> r -> a -- Get r a
type SetField :: forall (k::Kind) . k -> Type -> Type -> Constraint
class SetField x r a | x r -> a where
setField :: Proxy x -> r -> a -> r -- Set r a
hasField :: forall x r a . (HasField x r a, SetField x r a) => Proxy x -> r -> (a, a -> r) -- GetSet r a
hasField p r = (getField p r, setField p r)
composeSet :: forall a b c . GetSet a b -> (b -> c -> b) -> (a -> c -> a)
composeSet gs1 b_to_c_to_b a c =
case gs1 a of
(b, b_to_a) -> b_to_a (b_to_c_to_b b c)