Util/Either.hs

   1 module Util.Either where
   2
   3 isLeft :: Either a b -> Bool
   4 isLeft (Left _) = True
   5 isLeft _        = False
   6
   7 isRight :: Either a b -> Bool
   8 isRight = not . isLeft
   9
  10 doLeft :: Monad m => (a -> m ()) -> Either a b -> m ()
  11 doLeft f (Left x) = f x
  12 doLeft _ _        = return ()
  13