Safe Haskell	Safe
Language	Haskell2010

Data.EqP

Synopsis

class (forall a. Eq (f a)) => EqP (f :: k -> Type) where
- eqp :: f a -> f b -> Bool

Documentation

class (forall a. Eq (f a)) => EqP (f :: k -> Type) where #

Heterogenous lifted equality.

This class is stronger version of Eq1 from base

class (forall a. Eq a => Eq (f a)) => Eq1 f where
    liftEq :: (a -> b -> Bool) -> f a -> f b -> Bool

as we don't require a a -> b -> Bool function.

Morally Eq1 should be a superclass of EqP, but it cannot be, as GHC wouldn't allow EqP to be polykinded. https://gitlab.haskell.org/ghc/ghc/-/issues/22682

Laws

reflexivity: eqp x x ≡ True
symmetry: eqp x y ≡ eqp y x
transitivity: eqp x y ≡ eqp y z ≡ True ⇒ eqp x z ≡ True
compatibility: eqp x y ≡ x == y
extensionality: eqp x y ≡ True ⇒ f x == f y ≡ True for polymorphic f :: forall x. f x -> a and Eq a.

Note: P stands for phantom.

Since: 1.0.5

Methods

eqp :: f a -> f b -> Bool #

Instances

Instances details

EqP SNat #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k) (b :: k). SNat a -> SNat b -> Bool #
EqP SChar #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k) (b :: k). SChar a -> SChar b -> Bool #
EqP SSymbol #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k) (b :: k). SSymbol a -> SSymbol b -> Bool #
EqP StableName #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k) (b :: k). StableName a -> StableName b -> Bool #
EqP (Proxy :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k0) (b :: k0). Proxy a -> Proxy b -> Bool #
EqP (TypeRep :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k0) (b :: k0). TypeRep a -> TypeRep b -> Bool #
Eq a => EqP (Const a :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b :: k0). Const a a0 -> Const a b -> Bool #
EqP ((:~:) a :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b :: k0). (a :~: a0) -> (a :~: b) -> Bool #
(EqP a, EqP b) => EqP (Product a b :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b0 :: k0). Product a b a0 -> Product a b b0 -> Bool #
(EqP a, EqP b) => EqP (Sum a b :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b0 :: k0). Sum a b a0 -> Sum a b b0 -> Bool #
EqP ((:~~:) a :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b :: k0). (a :~~: a0) -> (a :~~: b) -> Bool #
(EqP a, EqP b) => EqP (a :*: b :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a0 :: k0) (b0 :: k0). (a :: b) a0 -> (a :: b) b0 -> Bool #
(EqP f, EqP g) => EqP (f :+: g :: k -> Type) #
Instance details Defined in Data.EqP Methods eqp :: forall (a :: k0) (b :: k0). (f :+: g) a -> (f :+: g) b -> Bool #