On Wed, Apr 23, 2008 at 11:29:42AM -0700, Simon Marlow wrote:
So now we have:
Prelude System.Process> readProcessMayFail "ls" ["/foo"] "" (ExitFailure 2,"ls: /foo: No such file or directory\n") Prelude System.Process> readProcess "ls" ["/foo"] "" *** Exception: readProcess: ls: failed
Look ok?
Looks fine as an API. As an implementation, I'd prefer for the exception thrown to include stderr (and wouldn't mind if the output didn't include stderr). It'd be much nicer if we had: Prelude System.Process> readProcess "ls" ["/foo"] "" *** Exception: readProcess: ls /foo: No such file or directory This would mean that correct programs could use readProcess without sacrificing nice feedback when something unusual happens. Of course, we can't guarantee that stderr will give any hint as to what went wrong, but that's not our bug. We could also potentially include both stdout and stderr, or just the last few lines of the stdout/stderr combination. But it'd be nice to be able to use readProcess rather than being forced to write our own in order to give better error messages to our users. -- David Roundy Department of Physics Oregon State University