Conversion.hs

module Pipes.Data.Conversion where

import Prelude (const)

import Data.Maybe (Maybe(..),maybe)
import Data.Either (Either(..),either)
import Data.Monoid

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 => (a -> b) -> Maybe a -> b
maybeToEither = maybe mempty