initial commit

2016-04-07 15:22:44 -04:00
commit 29b854cf98
15 changed files with 656 additions and 0 deletions
@@ -0,0 +1,22 @@
+module P.Either (
+  maybeToLeft
+, maybeToRight
+, leftToMaybe
+, rightToMaybe
+, maybeToEither
+) where
+
+leftToMaybe :: Either l r -> Maybe l
+leftToMaybe = either Just (const Nothing)
+
+rightToMaybe :: Either l r -> Maybe r
+rightToMaybe = either (const Nothing) Just
+
+maybeToRight :: l -> Maybe r -> Either l r
+maybeToRight l = maybe (Left l) Right
+
+maybeToLeft :: r -> Maybe l -> Either l r
+maybeToLeft r = maybe (Right r) Left
+
+maybeToEither :: Monoid b => Maybe a -> Either b a
+maybeToEither = maybe mempty