-- Создан:  Ср 28 сен 2016 10:18:53
-- Изменен: Чт 29 сен 2016 11:18:07

import System.Environment
import Data.WAVE
-- import Data.List

--Выбор канала из пары
chL :: [a] -> a
chL pair = pair!!0

chR :: [a] -> a
chR pair = pair!!1

audioread :: String -> String -> [Char] -> IO ()
audioread samples file ch = do
	w <- getWAVEFile file
	mapM_ print (map (sampleToDouble . channel) (take (read samples::Int) $ waveSamples w)) where
		channel (xs)
			| ch == ['R'] = chR xs
			| ch == ['L'] = chL xs
			| otherwise  = chL xs

main :: IO ()
main = do
	cmd <- getArgs
	case cmd of
	  [samples, file, ch] -> audioread samples file ch
	  [samples, file]     -> audioread samples file ['L']
	  _                   -> putStrLn "Usage: audioread [samples] [file.wav] [L/R]"