import System.Cmd
import System.Environment

main :: IO ()
main = do
    args <- getArgs
    case args of
        []         -> usage
        (cmd:rest) -> parseBefore cmd rest
    where
    parseBefore cmd rest = case break (== "--") (reverse rest) of
        (_, [])             -> parseAfter cmd [] rest
        (after, (_:before)) -> parseAfter cmd before (reverse after)
    parseAfter cmd before rest = case break (== "---") rest of
        (_, [])         -> run cmd before rest []
        (xs, (_:after)) -> run cmd before xs after

run :: String -> [String] -> [String] -> [String] -> IO ()
run cmd before args after = (`mapM_` args) $ \arg -> do
    rawSystem cmd (before ++ (arg:after))

usage :: IO ()
usage = mapM_ putStrLn
    [ ""
    , "Usage: mdo COMMAND [BEFORE... --] ITEMS... [--- AFTER...]"
    , ""
    , "    Run COMMAND on each of the ITEMS."
    , ""
    , "    Arguments in BEFORE are used as initial arguments to each invocation."
    , ""
    , "    Arguments in AFTER are used as trailing arguments to each invocation."
    , ""
    ]