yogsototh/elm
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add type annotations to Either.

Browse source
This commit is contained in:
evancz 2013-02-07 10:54:21 -08:00
parent 3c245ed612
commit 90304e69fc
1 changed files with 10 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
core-elm/Either.elm
View file

@ -1,12 +1,22 @@
data Either a b = Left a | Right b
either : (a -> c) -> (b -> c) -> Either a b -> c
either f g e = case e of { Left x -> f x ; Right y -> g y }
isLeft : Either a b -> Bool
isLeft e = case e of { Left _ -> True ; _ -> False }
isRight : Either a b -> Bool
isRight e = case e of { Right _ -> True ; _ -> False }
lefts : [Either a b] -> [a]
lefts = Elm.List.filter isLeft
rights : [Either a b] -> [b]
rights = Elm.List.filter isRight
partition : [Either a b] -> ([a],[b])
partition = Elm.List.partition isLeft