Modulesop-extras-0.4.1.1Haskell2010

Data.SOP.NonEmpty

Type-level non-empty lists

2 types
1 class
9 values

Packagesop-extras-0.4.1.1
Exports12
LanguageHaskell2010
LicenceApache-2.0
SourceNonEmpty.hs

datadata NonEmpty (xs :: [Type]) a where

Non-empty variation on AtMost

Constructors

NonEmptyOne :: !a -> NonEmpty (x ': xs1) a
NonEmptyCons :: !a -> !NonEmpty xs1 a -> NonEmpty (x ': xs1) a

Instances6Functor, Applicative, Foldable, Traversable, Eq, Show

Functor (NonEmpty xs)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty
(IsNonEmpty xs, SListI xs) => Applicative (NonEmpty xs)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty
Foldable (NonEmpty xs)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty
Traversable (NonEmpty xs)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty
Eq a => Eq (NonEmpty xs a)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty
Show a => Show (NonEmpty xs a)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty

Proofs

3 declarations

classclass IsNonEmpty (xs :: [a]) where

Methods

isNonEmpty :: proxy xs -> ProofNonEmpty xs

Instances1IsNonEmpty

IsNonEmpty (x ': xs)Defined in sop-extras-0.4.1.1 · Data.SOP.NonEmpty

datadata ProofNonEmpty (xs :: [a]) where

Constructors

ProofNonEmpty :: Proxy x -> Proxy xs1 -> ProofNonEmpty (x ': xs1)

valuecheckIsNonEmpty :: SListI xs => Proxy xs -> Maybe (ProofNonEmpty xs)

Working with NonEmpty

8 declarations

valuenonEmptyFromList :: SListI xs => [a] -> Maybe (NonEmpty xs a)

Build a NonEmpty from a list. Returns Nothing when the list is empty or when it's longer than xs.

valuenonEmptyHead :: NonEmpty xs a -> a

Analogue of head

valuenonEmptyInit :: NonEmpty xs a -> (Maybe (NonEmpty xs a), a)

Analogue of init

valuenonEmptyLast :: NonEmpty xs a -> a

Analogue of last

valuenonEmptyMapOne

:: Alternative m
=> a -> m a
-> NonEmpty xs a
-> m (NonEmpty xs a)

Apply the specified function to exactly one element

valuenonEmptyMapTwo

:: Alternative m
=> a -> m a
-> a -> a -> m (a, a)
-> NonEmpty xs a
-> m (NonEmpty xs a)

Variation on nonEmptyMapOne where we try to apply the function to pairs of elements

valuenonEmptyStrictPrefixes :: NonEmpty xs a -> [NonEmpty xs a]

A strict prefixes

   nonEmptyStrictPrefixes (fromJust (nonEmptyFromList [1..4]))
== [ NonEmptyOne  1
   , NonEmptyCons 1 $ NonEmptyOne  2
   , NonEmptyCons 1 $ NonEmptyCons 2 $ NonEmptyOne 3
   ]

valuenonEmptyToList :: NonEmpty xs a -> [a]

Convert a NonEmpty to a list.