module Hmake where
import System.Cmd
import System.Directory
import Control.Monad

type Dependency = String
type Target = String

outOfDate :: String -> String -> IO Bool
outOfDate dep target = do
	tgtExist <- doesFileExist target
	if (not tgtExist)
		then return True
		else liftM2 (>) (getModificationTime dep) (getModificationTime target)
		
deps ->> cmd = \target -> do
	xdeps <- deps
	isOutOfDate <- (sequence (map (\dep -> outOfDate dep target) xdeps)) >>= return.or
	case isOutOfDate of
		True -> putStrLn (target ++ " is out of date with its dependencies")
		False -> putStr ""

	if isOutOfDate then ((cmd xdeps target) >> return target) else return target

tcmd >>- target = (tcmd target) >> return [target]
 
ccompile deps target = system("gcc -c " ++ (head deps) ++ " -o " ++ target)

link deps target = system("gcc  " ++ (head deps) ++ " -o " ++ target)