可変長引数のメモ

mutableArgLengthFunc.hs

{-# LANGUAGE FlexibleInstances #-}

class Watashi a where
	next :: [String] -> a

instance Watashi String where
	next = unwords . reverse

instance (Watashi r) => Watashi (String -> r) where
	next xs b = next $ b:xs

watashi :: (Watashi a) => a
watashi = next []

main :: IO ()
main = do
	putStrLn $ watashi
	putStrLn $ watashi " ( ^o^)"
	putStrLn $ watashi " ( ^o^)!" "     " "(^o^ )"
	putStrLn $ watashi " ( ^o^)  (^o^ )"
	putStrLn $ watashi " ( ^o(^o^ )"
	putStrLn $ watashi " ( ^o^)" "(^q^)" "(^o^ )"