Type.Membership.Internal

Membership

data Membership (xs :: [k]) (x :: k)

A witness that of x is a member of a type level set xs.

Instances

Eq (Membership xs x)

Defined in Type.Membership.Internal

Methods

(==) :: Membership xs x -> Membership xs x -> Bool

(/=) :: Membership xs x -> Membership xs x -> Bool

Ord (Membership xs x)

Defined in Type.Membership.Internal

Methods

compare :: Membership xs x -> Membership xs x -> Ordering

(<) :: Membership xs x -> Membership xs x -> Bool

(<=) :: Membership xs x -> Membership xs x -> Bool

(>) :: Membership xs x -> Membership xs x -> Bool

(>=) :: Membership xs x -> Membership xs x -> Bool

max :: Membership xs x -> Membership xs x -> Membership xs x

min :: Membership xs x -> Membership xs x -> Membership xs x

Show (Membership xs x)

Defined in Type.Membership.Internal

Methods

showsPrec :: Int -> Membership xs x -> ShowS

show :: Membership xs x -> String

showList :: [Membership xs x] -> ShowS

Semigroup (Membership xs x)

Defined in Type.Membership.Internal

Methods

(<>) :: Membership xs x -> Membership xs x -> Membership xs x

sconcat :: NonEmpty (Membership xs x) -> Membership xs x

stimes :: Integral b => b -> Membership xs x -> Membership xs x

Lift (Membership xs x)

Defined in Type.Membership.Internal

Methods

lift :: Membership xs x -> Q Exp

NFData (Membership xs x)

Defined in Type.Membership.Internal

Methods

rnf :: Membership xs x -> ()

Hashable (Membership xs x)

Defined in Type.Membership.Internal

Methods

hashWithSalt :: Int -> Membership xs x -> Int

hash :: Membership xs x -> Int

Pretty (Membership xs x)

Defined in Type.Membership.Internal

Methods

pretty :: Membership xs x -> Doc ann

prettyList :: [Membership xs x] -> Doc ann

getMemberId :: Membership xs x -> Int

get the position as an Int.

mkMembership :: Int -> Q Exp

Generates a Membership that corresponds to the given ordinal (0-origin).

leadership :: Membership (x ': xs) x

This Membership points to the first element

nextMembership :: Membership xs y -> Membership (x ': xs) y

The next membership

testMembership :: Membership (y ': xs) x -> ((x :~: y) -> r) -> (Membership xs x -> r) -> r

Embodies a type equivalence to ensure that the Membership points the first element.

compareMembership :: Membership xs x -> Membership xs y -> Either Ordering (x :~: y)

Compare two Memberships.

impossibleMembership :: Membership '[] x -> r

There is no Membership of an empty list.

reifyMembership :: Int -> (forall x. Membership xs x -> r) -> r

Make up a Membership from an integer.

Member class

class Member xs x where

x is a member of xs

Methods

membership :: Membership xs x

Instances

(Elaborate x (FindType x xs) ~ (Expecting pos :: Elaborated k Nat), KnownNat pos) => Member (xs :: [k]) (x :: k)

Defined in Type.Membership.Internal

Methods

membership :: Membership xs x

type (∈) x xs = Member xs x

Unicode flipped alias for Member

type family FindType (x :: k) (xs :: [k]) :: [Nat] where ...

FindType types

Equations

FindType x (x ': xs) = 0 ': MapSucc (FindType x xs)

FindType x (y ': ys) = MapSucc (FindType x ys)

FindType x '[] = '[]

Association

data Assoc k v

The kind of key-value pairs

Constructors

k :> v infix 0

type (>:) = (:>)

A synonym for (:>)

class Lookup xs k v | k xs -> v where

Lookup xs k v is essentially identical to (k :> v) ∈ xs , but the type v is inferred from k and xs.

Methods

association :: Membership xs (k :> v)

Instances

(Elaborate k2 (FindAssoc 0 k2 xs) ~ (Expecting (n :> v2) :: Elaborated k1 (Assoc Nat v1)), KnownNat n) => Lookup (xs :: [Assoc k1 v1]) (k2 :: k1) (v2 :: v1)

Defined in Type.Membership.Internal

Methods

association :: Membership xs (k2 :> v2)

type family FindAssoc (n :: Nat) (key :: k) (xs :: [Assoc k v]) where ...

Find a type associated to the specified key.

Equations

FindAssoc n k ((k :> v) ': xs) = (n :> v) ': FindAssoc (1 + n) k xs

FindAssoc n k ((k' :> v) ': xs) = FindAssoc (1 + n) k xs

FindAssoc n k '[] = '[]

Sugar

type family Elaborate (key :: k) (xs :: [v]) :: Elaborated k v where ...

Make the result more readable

Equations

Elaborate k '[] = Missing k

Elaborate k '[x] = Expecting x

Elaborate k xs = Duplicate k

data Elaborated k v

A readable type search result

Constructors

Expecting v

Missing k

Duplicate k

HList

data HList (h :: k -> *) (xs :: [k]) where

Constructors

HNil :: HList h '[]

HCons :: h x -> HList h xs -> HList h (x ': xs) infixr 5

hfoldrWithIndex :: forall h r xs. (forall x. Membership xs x -> h x -> r -> r) -> r -> HList h xs -> r

htraverseWithIndex :: forall f g h xs. Applicative f => (forall x. Membership xs x -> g x -> f (h x)) -> HList g xs -> f (HList h xs)

Miscellaneous

module Data.Type.Equality

module Data.Proxy