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Merge pull request #74 from haskell-servant/wip-whitespace-comment

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servant: clean up some white spaces, add link explaining why Or works.
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Alp Mestanogullari 2015-05-16 08:28:28 +01:00
commit e59c03faa2
1 changed files with 24 additions and 22 deletions
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46
servant/src/Servant/Utils/Links.hs
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@ -138,15 +138,17 @@ data Link = Link
-- | If either a or b produce an empty constraint, produce an empty constraint.
type family Or (a :: Constraint) (b :: Constraint) :: Constraint where
-- This works because of:
-- https://ghc.haskell.org/trac/ghc/wiki/NewAxioms/CoincidentOverlap
Or () b = ()
Or a () = ()
-- | If both a or b produce an empty constraint, produce an empty constraint.
type family And (a :: Constraint) (b :: Constraint) :: Constraint where
And () () = ()
And () () = ()
-- | You may use this type family to tell the type checker that your custom type
-- may be skipped as part of a link. This is useful for things like
-- | You may use this type family to tell the type checker that your custom
-- type may be skipped as part of a link. This is useful for things like
-- 'QueryParam' that are optional in a URI and do not affect them if they are
-- omitted.
--
@ -162,30 +164,30 @@ type family IsElem' a s :: Constraint
-- | Closed type family, check if endpoint is within api
type family IsElem endpoint api :: Constraint where
IsElem e (sa :<|> sb) = Or (IsElem e sa) (IsElem e sb)
IsElem (e :> sa) (e :> sb) = IsElem sa sb
IsElem sa (Header x :> sb) = IsElem sa sb
IsElem sa (ReqBody y x :> sb) = IsElem sa sb
IsElem (e :> sa) (Capture x y :> sb) = IsElem sa sb
IsElem sa (QueryParam x y :> sb) = IsElem sa sb
IsElem sa (QueryParams x y :> sb) = IsElem sa sb
IsElem sa (QueryFlag x :> sb) = IsElem sa sb
IsElem sa (MatrixParam x y :> sb) = IsElem sa sb
IsElem sa (MatrixParams x y :> sb) = IsElem sa sb
IsElem sa (MatrixFlag x :> sb) = IsElem sa sb
IsElem (Get ct typ) (Get ct' typ) = IsSubList ct ct'
IsElem (Post ct typ) (Post ct' typ) = IsSubList ct ct'
IsElem (Put ct typ) (Put ct' typ) = IsSubList ct ct'
IsElem (Delete ct typ) (Delete ct' typ) = IsSubList ct ct'
IsElem e e = ()
IsElem e a = IsElem' e a
IsElem e (sa :<|> sb) = Or (IsElem e sa) (IsElem e sb)
IsElem (e :> sa) (e :> sb) = IsElem sa sb
IsElem sa (Header x :> sb) = IsElem sa sb
IsElem sa (ReqBody y x :> sb) = IsElem sa sb
IsElem (e :> sa) (Capture x y :> sb) = IsElem sa sb
IsElem sa (QueryParam x y :> sb) = IsElem sa sb
IsElem sa (QueryParams x y :> sb) = IsElem sa sb
IsElem sa (QueryFlag x :> sb) = IsElem sa sb
IsElem sa (MatrixParam x y :> sb) = IsElem sa sb
IsElem sa (MatrixParams x y :> sb) = IsElem sa sb
IsElem sa (MatrixFlag x :> sb) = IsElem sa sb
IsElem (Get ct typ) (Get ct' typ) = IsSubList ct ct'
IsElem (Post ct typ) (Post ct' typ) = IsSubList ct ct'
IsElem (Put ct typ) (Put ct' typ) = IsSubList ct ct'
IsElem (Delete ct typ) (Delete ct' typ) = IsSubList ct ct'
IsElem e e = ()
IsElem e a = IsElem' e a
type family IsSubList a b :: Constraint where
IsSubList '[] b = ()
IsSubList '[] b = ()
IsSubList '[x] (x ': xs) = ()
IsSubList '[x] (y ': ys) = IsSubList '[x] ys
IsSubList (x ': xs) y = IsSubList '[x] y `And` IsSubList xs y
IsSubList (x ': xs) y = IsSubList '[x] y `And` IsSubList xs y
-- Phantom types for Param
data Matrix