On Thu, Oct 26, 2006 at 08:16:47PM +0400, Bulat Ziganshin wrote:
Hello David,
Thursday, October 26, 2006, 8:08:42 PM, you wrote:
In case I've been too vague, what I mean is that I'd like it if one could ensure that code such as
withFile "filename" ReadMode return >>= hGetContents
statically fails, rather than failing at runtime with a file handle closed
and how about passing file handle to another thread? ;)
Good point. I wonder if it would make sense to (not now, but eventually, in an ideal haskell standard library) give IO a phantom type like ST has, which by default would refer to the thread involved, and then we could (at least optionally) open files with a thread-specific handle that can't be passed to another handle. Which could also be used to restrict withFile itself, something like withFile :: FilePath -> Mode -> (Handle t' -> IO t' ()) -> IO t () ? Not sure how that would work out with threads, but I'm sure it's possible... -- David Roundy Dept. of Physics Oregon State University