ljsc

(x:xs) `minus` yys@(y:ys)
  | x == y    =     xs `minus` ys
  | otherwise = x : xs `minus` yys

naturals = [1..]
evens    = [2,4..]
odds     = naturals `minus` evens

{-

patrickt

{-# LANGUAGE GeneralizedNewtypeDeriving, OverloadedStrings, ViewPatterns #-}

module Main where
  
  import Control.Applicative
  import Data.ByteString (ByteString)
  import qualified Data.ByteString as B
  import Data.Char
  import Data.Monoid
  import Data.Scotty