eeva/servant
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

servant: clean up some white spaces, add link explaining why Or works.

Browse source
This commit is contained in:
Christian Marie 2015-05-14 00:07:57 +10:00
parent c87b846815
commit 13fcb4f3f1
1 changed files with 25 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
servant/src/Servant/Utils/Links.hs
View file

@ -137,6 +137,9 @@ data Link = Link
} deriving Show } deriving Show
-- | If either a or b produce an empty constraint, produce an empty constraint. -- | If either a or b produce an empty constraint, produce an empty constraint.
--
-- This works because of:
-- https://ghc.haskell.org/trac/ghc/wiki/NewAxioms/CoincidentOverlap
type family Or (a :: Constraint) (b :: Constraint) :: Constraint where type family Or (a :: Constraint) (b :: Constraint) :: Constraint where
Or () b = () Or () b = ()
Or a () = () Or a () = ()
@ -145,8 +148,8 @@ type family Or (a :: Constraint) (b :: Constraint) :: Constraint where
type family And (a :: Constraint) (b :: Constraint) :: Constraint where 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 -- | You may use this type family to tell the type checker that your custom
-- may be skipped as part of a link. This is useful for things like -- 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 -- 'QueryParam' that are optional in a URI and do not affect them if they are
-- omitted. -- omitted.
-- --