Moduleservant-0.20.2Haskell2010

Servant.API.UVerb.Union

Type-level code for implementing and using UVerb. Heavily inspired by world-peace.

2 types
2 values

Packageservant-0.20.2
Exports7
LanguageHaskell2010
LicenceBSD-3-Clause
SourceUnion.hs

typetype IsMember (a :: u) (as :: [u]) = (Unique as, CheckElemIsMember a as, UElem a as)

familytype family Unique (xs :: [k]) :: Constraint where

Check whether all values in a type-level list are distinct. This will throw a nice error if there are any duplicate elements in the list.

Equations

Unique xs = If (Nubbed xs == 'True) () (TypeError (DuplicateElementError xs))

typetype Union = NS I

methodinject :: f x -> NS f xs

methodeject :: NS f xs -> Maybe (f x)

valuefoldMapUnion

:: All c as
=> Proxy c
-> forall x. c x => x -> a
-> Union as
-> a

Convenience function to apply a function to an unknown union element using a type class. All elements of the union must have instances in the type class, and the function is applied unconditionally.