指定したディレクトリを再帰的に探索して末端のパスのリストを返します。#haskell

getTerminals.hs

module Main where
import Directory
import Data.List
import System

main = do [ root ] <- getArgs
          cnt <- getTerminals [] root

getTerminals root path
     = do b <- doesDirectoryExist pth
          c <- doesFileExist pth
          case (b,c,null path) of
            (False,False,_) -> error $ pth ++ " was not found."
            (True,_,False)  -> _subGetTerminals
            _ -> return [pth]
     where
       pth = if null root then path else root ++ "/" ++ path
       _subGetTerminals
           = do b <- getDirectoryContents pth
                c <- mapM (getTerminals pth) (b \\ [".",".."])
                return $ concat c