Copyright	Copyright (C) 2015 Kyle Carter
License	BSD3
Maintainer	Kyle Carter <kylcarte@indiana.edu>
Stability	experimental
Portability	RankNTypes
Safe Haskell	None
Language	Haskell2010

Data.Type.Option

Description

A type combinator for type-level Maybes, lifting (f :: k -> *) to (Option f :: Maybe k -> *).

Synopsis

Documentation

data Option f :: Maybe k -> * where Source #

Constructors

Nothing_ :: Option f Nothing
Just_ :: !(f a) -> Option f (Just a)

Instances

(Witness p q (f a), (~) (Maybe k) x (Just k a)) => Witness p q (Option k f x) Source #
Associated Types type WitnessC (p :: Constraint) (q :: Constraint) (Option k f x) :: Constraint Source # Methods (\\) :: p => (q -> r) -> Option k f x -> r Source #
Traversable1 (Maybe k) k (Option k) Source #
Methods traverse1 :: Applicative h => (forall a. f a -> h (g a)) -> t f b -> h (t g b) Source #
Foldable1 (Maybe k) k (Option k) Source #
Methods foldMap1 :: Monoid m => (forall a. f a -> m) -> t f b -> m Source #
Functor1 (Maybe k) k (Option k) Source #	We can take a natural transformation of `(forall x. f x -> g x)` to a natural transformation of `(forall mx. Option f mx -> Option g mx)`.
Methods map1 :: (forall a. f a -> g a) -> t f b -> t g b Source #
Known (Maybe k) (Option k f) (Nothing k) Source #
Associated Types type KnownC (Option k f) (Nothing k :: Option k f -> *) (a :: Option k f) :: Constraint Source # Methods known :: Nothing k a Source #
Known a f a1 => Known (Maybe a) (Option a f) (Just a a1) Source #
Associated Types type KnownC (Option a f) (Just a a1 :: Option a f -> *) (a :: Option a f) :: Constraint Source # Methods known :: Just a a1 a Source #
MaybeC ((<$>) Constraint * Eq ((<$>) * k f m)) => Eq (Option k f m) Source #
Methods (==) :: Option k f m -> Option k f m -> Bool # (/=) :: Option k f m -> Option k f m -> Bool #
(MaybeC ((<$>) Constraint * Eq ((<$>) * k f m)), MaybeC ((<$>) Constraint * Ord ((<$>) * k f m))) => Ord (Option k f m) Source #
Methods compare :: Option k f m -> Option k f m -> Ordering # (<) :: Option k f m -> Option k f m -> Bool # (<=) :: Option k f m -> Option k f m -> Bool # (>) :: Option k f m -> Option k f m -> Bool # (>=) :: Option k f m -> Option k f m -> Bool # max :: Option k f m -> Option k f m -> Option k f m # min :: Option k f m -> Option k f m -> Option k f m #
MaybeC ((<$>) Constraint * Show ((<$>) * k f m)) => Show (Option k f m) Source #
Methods showsPrec :: Int -> Option k f m -> ShowS # show :: Option k f m -> String # showList :: [Option k f m] -> ShowS #
type WitnessC p q (Option k f x) Source #
type WitnessC p q (Option k f x) = Witness p q (f (FromJust k x))
type KnownC (Maybe k) (Option k f) (Nothing k) Source #
type KnownC (Maybe k) (Option k f) (Nothing k) = ØC
type KnownC (Maybe a) (Option a f) (Just a a1) Source #
type KnownC (Maybe a) (Option a f) (Just a a1) = Known a f a1

option :: (forall a. m ~ Just a => f a -> r) -> (m ~ Nothing => r) -> Option f m -> r Source #

Eliminator for Option f.