1 Beautiful Programming Language and Beautiful Testing 2 Haskeller Haskeller 3 Haskeller (Doctest QuickCheck ) github 4 Haskeller 5 Haskell Platform 2011.4.0.0 Glasgow Haskell Compiler + 23 19 8 5 10 6 Q) Haskeller A) 7 Q) A) Haskell 8 Haskell 9 Haskell (+) :: Num a => a -> a -> a sort :: Ord a => [a] -> [a] delete :: Eq a => a -> [a] -> [a] hGetLine :: Handle -> IO String writeFile :: FilePath ->