jgoerzen:
On Wed, Dec 13, 2006 at 04:19:58PM +1100, Donald Bruce Stewart wrote:
In particular, you seem to be wanting my pipeBoth function.
Note that your proposed String -> IO String function type is insufficient because it does not provide a way to evaluate the return value of the function.
this kind of functionality seems to be expected by new users (its one of the more common questions on #haskell).
Is System.Cmd.Utils in a position to be moved into base alongside System.Cmd and System.Process? It seems quite fundamental for getting work done quickly for script-like haskell programs.
It could go under System.Posix perhaps. It relies quite heavily on functionality provided by the unix package and the System.Posix.* tree.
Can't we do something like this, on top of System.Process? Do we need unix* stuff anymore? (modulo getting rid of the non-portable stuff) module Lib.Process (popen) where import System.Exit import System.IO import System.Process import Control.Concurrent (forkIO, newEmptyMVar, putMVar, takeMVar) import qualified Control.Exception popen :: FilePath -> [String] -> Maybe String -> IO (String,String,ExitCode) popen file args minput = Control.Exception.handle (\e -> return ([],show e,error (show e))) $ do (inp,out,err,pid) <- runInteractiveProcess file args Nothing Nothing case minput of Just input -> hPutStr inp input >> hClose inp -- importante! Nothing -> return () output <- hGetContents out errput <- hGetContents err forkIO (Control.Exception.evaluate (length output)) forkIO (Control.Exception.evaluate (length errput)) e <- Control.Exception.catch (waitForProcess pid) (\_ -> return ExitSuccess) return (output,errput,e)