-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On May 7, 2009, at 14:53 , Thomas Friedrich wrote:
writeFeatures :: [String] -> IO () writeFeatures cs = Exc.bracket (openFile training AppendMode) hClose (\h -> goo h) where goo h = go 1 cs where go :: Int -> [String] -> IO () go n [] = putStrLn "Features written." go n (c:cs) = do features <- makeFeatures n c -- makeFeatures :: Int -> String -> IO String hPutStr h features go (n+1) cs
And the file that is produced here is needed in the next function.
You probably want to rethink how you're doing this. My own thought is that you have something like:
runThis :: FilePath -> [String] -> String -> IO (MVar String) runThis cmd args inp = do mvar <- newEmptyMVar forkIO (readProcess cmd args inp >>= writeMVar mvar) return mvar
runOne launches in the background, you synchronize by doing takeMVar on the returned MVar (which will give you the output, if any). Even if there is no useful output you can still create data dependencies to insure things wait for what they need --- and that is exactly what you want to do: insure that there are data dependencies to constrain when programs are run. Otherwise, you'll have to settle for linear execution. - -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.10 (Darwin) iEYEARECAAYFAkoDUeAACgkQIn7hlCsL25VH/gCghNldOSJnChoHrJwjeaboseU4 Z28An39bR2DAAlP6K9g00eb+NnHhKZSU =NHpz -----END PGP SIGNATURE-----