diff options
Diffstat (limited to 'apps/ListPath.hs')
-rw-r--r-- | apps/ListPath.hs | 66 |
1 files changed, 33 insertions, 33 deletions
diff --git a/apps/ListPath.hs b/apps/ListPath.hs index 75f1b27..b964998 100644 --- a/apps/ListPath.hs +++ b/apps/ListPath.hs @@ -4,33 +4,33 @@ - See LICENSE.txt for details. -} -module Main ( main ) where +module Main (main) where import System.Console.GetOpt -import System.Directory ( doesDirectoryExist ) -import System.Environment ( getArgs, getProgName ) -import System.Exit ( exitFailure, exitSuccess ) -import System.IO ( hPutStr, stderr ) +import System.Directory (doesDirectoryExist) +import System.Environment (getArgs, getProgName) +import System.Exit (exitFailure, exitSuccess) +import System.IO (hPutStr, stderr) import qualified Environment main :: IO () main = do - rawArgs <- getArgs - case getOpt Permute optionDescription rawArgs of - (actions, args, []) -> do - options <- foldl (>>=) (return defaultOptions) actions - case args of - [] -> listPath options - _ -> invalidNumberOfArguments - (_, _, errorMessages) -> exitWithUsageErrors errorMessages + rawArgs <- getArgs + case getOpt Permute optionDescription rawArgs of + (actions, args, []) -> do + options <- foldl (>>=) (return defaultOptions) actions + case args of + [] -> listPath options + _ -> invalidNumberOfArguments + (_, _, errorMessages) -> exitWithUsageErrors errorMessages listPath :: Options -> IO () listPath options = do - val <- Environment.getEnv $ name options - mapM_ printPath $ Environment.splitPaths val - where - printPath p = do + val <- Environment.getEnv $ name options + mapM_ printPath $ Environment.splitPaths val + where + printPath p = do exists <- doesDirectoryExist p putStrLn $ (if exists then "+" else "-") ++ " " ++ p @@ -41,32 +41,32 @@ defaultOptions = Options { name = "PATH" } buildHelpMessage :: IO String buildHelpMessage = do - header <- buildHeader - return $ usageInfo header optionDescription - where - buildHeader :: IO String - buildHeader = do + header <- buildHeader + return $ usageInfo header optionDescription + where + buildHeader :: IO String + buildHeader = do progName <- getProgName return $ "Usage: " ++ progName ++ " [OPTIONS...]\nOptions:" exitWithHelpMessage :: a -> IO b exitWithHelpMessage _ = do - helpMessage <- buildHelpMessage - putStr helpMessage - exitSuccess + helpMessage <- buildHelpMessage + putStr helpMessage + exitSuccess exitWithUsageErrors :: [String] -> IO a exitWithUsageErrors errorMessages = do - hPutStr stderr $ concatMap ("Usage error: " ++) errorMessages - helpMessage <- buildHelpMessage - hPutStr stderr helpMessage - exitFailure + hPutStr stderr $ concatMap ("Usage error: " ++) errorMessages + helpMessage <- buildHelpMessage + hPutStr stderr helpMessage + exitFailure invalidNumberOfArguments :: IO a invalidNumberOfArguments = exitWithUsageErrors ["invalid number of arguments\n"] optionDescription :: [OptDescr (Options -> IO Options)] -optionDescription = [ - Option "n" ["name"] (ReqArg (\s opts -> return opts { name = s }) "NAME") "set the variable name ('PATH' by default)", - Option "h" ["help"] (NoArg exitWithHelpMessage) "show this message and exit" - ] +optionDescription = + [ Option "n" ["name"] (ReqArg (\s opts -> return opts { name = s }) "NAME") "set the variable name ('PATH' by default)" + , Option "h" ["help"] (NoArg exitWithHelpMessage) "show this message and exit" + ] |