Data.Extensible.Class

Class

class Extensible f p q t where

This class allows us to use pieceAt for both sums and products.

Methods

pieceAt :: Membership xs x -> p (h x) (f (h x)) -> q (t h xs) (f (t h xs))

Instances

Functor f => Extensible k * f (->) (->) ((:*) k)

(Applicative f, Choice p) => Extensible k * f p p ((:|) k)

Extensible k k f (LabelPhantom k * k s) q t

piece :: (x ∈ xs, Extensible f p q t) => p (h x) (f (h x)) -> q (t h xs) (f (t h xs))

Accessor for an element.

pieceAssoc :: (Associate k v xs, Extensible f p q t) => p (h (k :> v)) (f (h (k :> v))) -> q (t h xs) (f (t h xs))

Like piece, but reckon membership from its key.

Membership

data Membership xs x

The position of x in the type level set xs.

Instances

Typeable ([k] -> k -> *) (Membership k)

Eq (Membership k xs x)

Ord (Membership k xs x)

Show (Membership k xs x)

mkMembership :: Int -> Q Exp

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

Member

class Member xs x where

Methods

membership :: Membership xs x

Instances

((~) (Elaborated k Nat) (Elaborate k Nat x (FindType k x xs)) (Expecting k Nat pos), KnownPosition Nat pos) => Member k xs x

remember :: forall xs x r. Membership xs x -> (Member xs x => r) -> r

Remember that Member xs x from Membership.

type (∈) x xs = Member xs x

Unicode flipped alias for Member

type family FindType x xs :: [Nat]

FindType types

Equations

FindType x (x : xs) = Zero : 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

Instances

Associate k k1 k2 v xs => Associated (Assoc k k) xs ((:>) k k k v)

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

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

Methods

association :: Membership xs (k :> v)

Instances

((~) (Elaborated k (Assoc Nat k1)) (Elaborate k (Assoc Nat k1) k2 (FindAssoc k1 k k1 k2 xs)) (Expecting k (Assoc Nat k1) ((:>) Nat k1 n v)), KnownPosition Nat n) => Associate k k k v xs

type family FindAssoc key xs

Equations

FindAssoc k ((k :> v) : xs) = (Zero :> v) : MapSuccKey (FindAssoc k xs)

FindAssoc k ((k' :> v) : xs) = MapSuccKey (FindAssoc k xs)

FindAssoc k [] = []

Sugar

type family Elaborate key xs :: Elaborated k v

Equations

Elaborate k [] = Missing k

Elaborate k `[x]` = Expecting x

Elaborate k xs = Duplicate k

data Elaborated k v

Constructors

Expecting v

Missing k

Duplicate k