On Tue, Jan 17, 2006 at 06:13:14PM +0000, Keean Schupke wrote: > Just made a few modifications and thought it might be useful to > people. I have rewritten the functions as > "liftR" and "bracketR" over a "MonadIO" monad interface (allowing > monad-transformers to be used). This is now > usable as Region library, as you can lift any arbitrary IO function > into a Region. I don't think I have overlooked anything, and I > think it is as safe as the original... [snip] > liftR :: (InRegion mark marks) => (h -> m a) -> Private mark h -> Region > marks m a > liftR f (Private h) = Region $ f h
This is not as safe. Try modifying your test2: > -- test2 = bracketR (openFile "/etc/services" ReadMode) (hClose) (\f -> > return f) > -- test2' = bracketR (openFile "/etc/services" ReadMode) (hClose) (\f -> > liftR return f) This returns the "Private" handle out of the region. Still, these functions would be useful for creating a library of region-safe operations. Andrew _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
