Data.HList.HList

A GADT HList implementation

Probably exists somewhere else already, but why add a dependency for something so simple.

Documentation

data HList :: [*] -> * where

Constructors

HNil :: HList '[]

(:+:) :: x -> HList xs -> HList (x ': xs) infixr 5

Instances

(Eq x, Eq (HList xs)) => Eq (HList ((:) * x xs))

Methods

(==) :: HList ((* ': x) xs) -> HList ((* ': x) xs) -> Bool

(/=) :: HList ((* ': x) xs) -> HList ((* ': x) xs) -> Bool

Eq (HList ([] *))

Methods

(==) :: HList [*] -> HList [*] -> Bool

(/=) :: HList [*] -> HList [*] -> Bool

(Show a, Show (HList b)) => Show (HList ((:) * a b))

Methods

showsPrec :: Int -> HList ((* ': a) b) -> ShowS

show :: HList ((* ': a) b) -> String

showList :: [HList ((* ': a) b)] -> ShowS

Show (HList ([] *))

Methods

showsPrec :: Int -> HList [*] -> ShowS

show :: HList [*] -> String

showList :: [HList [*]] -> ShowS

(Monoid x, Monoid (HList xs)) => Monoid (HList ((:) * x xs))

Methods

mempty :: HList ((* ': x) xs)

mappend :: HList ((* ': x) xs) -> HList ((* ': x) xs) -> HList ((* ': x) xs)

mconcat :: [HList ((* ': x) xs)] -> HList ((* ': x) xs)

Monoid (HList ([] *))

Methods

mempty :: HList [*]

mappend :: HList [*] -> HList [*] -> HList [*]

mconcat :: [HList [*]] -> HList [*]

type family Append (l1 :: [*]) (l2 :: [*]) :: [*]

Instances

type Append ([] *) l2

type Append ([] *) l2 = l2

type Append ((:) * car1 cdr2) l2

type Append ((:) * car1 cdr2) l2 = (:) * car1 (Append cdr2 l2)

hAppend :: HList ts1 -> HList ts2 -> HList (Append ts1 ts2)

class HInit l1 where

Minimal complete definition

hInit, hSplit

Methods

hInit :: forall l2. Proxy l2 -> HList (Append l1 l2) -> HList l1

hSplit :: forall l2. HList (Append l1 l2) -> (HList l1, HList l2)

Instances

HInit ([] *)

Methods

hInit :: Proxy [*] l2 -> HList (Append [*] l2) -> HList [*]

hSplit :: HList (Append [*] l2) -> (HList [*], HList l2)

HInit l1 => HInit ((:) * x l1)

Methods

hInit :: Proxy [*] l2 -> HList (Append ((* ': x) l1) l2) -> HList ((* ': x) l1)

hSplit :: HList (Append ((* ': x) l1) l2) -> (HList ((* ': x) l1), HList l2)