import System.Cmd
import System.IO
import System.Environment
import System.Process

data Version = Version String String
    deriving (Show)

main = do
    cs <- getArgs
    vs <- mapM getVersion cs
    print vs

-- get at this from header.mk somehow. via args. yes.
getVersion :: String -> IO Version
getVersion s = Version s `fmap` (run $ case s of
    "ghc"     -> "ghc-6.7.20070224   --version"
    "ghc-old" -> "ghc-6.6 --version"
    "ghc-asm" -> "ghc-6.6 --version"
    "ghci"    -> "ghci      --version"
    "hugs"    -> "echo ':q' | hugs | sed -n 's/.*\\(Version:[^_]*\\)_*/\\1/p'"
    "nhc98"   -> "nhc98 --version | sed '2d;s/.*: //'"
    "yhc"     -> "yhc -v"
    "jhc-grin"-> "jhc -V"
    "jhc-ghc" -> "jhc -V"
    "hbc"     -> "hbc -v 2>&1")

run s = do
    (ih,oh,eh,pid) <- runInteractiveCommand s
    hClose ih

    so <- hGetContents oh
    se <- hGetContents eh

    map length [so,se] `seq` return ()
    return (head . lines $ so ++ se)