Merge pull request #9 from purescript-contrib/no-alt

Remove Alt instances for Either

Author: paf31

docs/Module.md

@@ -68,12 +68,6 @@
 
 ### Type Class Instances
 
-    instance errorEitherAlt :: (Error e) => Alt (Either e)
-
-    instance errorEitherAlternative :: (Error e) => Alternative (Either e)
-
-    instance errorEitherPlus :: (Error e) => Plus (Either e)
-
     instance errorString :: Error String
 
 

src/Control/Monad/Error.purs

@@ -1,10 +1,5 @@
 module Control.Monad.Error where
 
-import Control.Alt
-import Control.Alternative
-import Control.Plus
-import Data.Either
-
 class Error a where
   noMsg :: a
   strMsg :: String -> a
@@ -13,11 +8,3 @@ instance errorString :: Error String where
   noMsg = ""
   strMsg = id
 
-instance errorEitherAlt :: (Error e) => Alt (Either e) where
-  (<|>) (Left _) n = n
-  (<|>) m _ = m
-
-instance errorEitherPlus :: (Error e) => Plus (Either e) where
-  empty = Left noMsg
-
-instance errorEitherAlternative :: (Error e) => Alternative (Either e)