work.hs

module Main where
import Safe
import Control.Applicative

main :: IO ()
main = do
  print $ sample ([] :: [Int])
  print $ sample [1]
  print $ sample [1,2]
  print $ sample [1,2,3,4,5]

sample :: Show a => [a] -> Maybe [String]
sample xs = zipWith hoge <$> Just xs <*> tailMay xs

hoge :: (Show a, Show b) => a -> b -> String
hoge x y = "<" ++ show x ++ ", " ++ show y ++ ">"