-\subsection{Try and bracket}
-%* *
-%*********************************************************
-
-The construct @try comp@ exposes errors which occur within a
-computation, and which are not fully handled. It always succeeds.
-
-These are the IO-only try/bracket. For the full exception try/bracket
-see hslibs/lang/Exception.lhs.
-
-\begin{code}
-try :: IO a -> IO (Either Exception a)
-try f = catch (do r <- f
- return (Right r))
- (return . Left)
-
-bracket :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
-bracket before after m = do
- x <- before
- rs <- try (m x)
- after x
- case rs of
- Right r -> return r
- Left e -> ioError e
-
--- variant of the above where middle computation doesn't want x
-bracket_ :: IO a -> (a -> IO b) -> IO c -> IO c
-bracket_ before after m = do
- x <- before
- rs <- try m
- after x
- case rs of
- Right r -> return r
- Left e -> ioError e
-\end{code}
-
-
-%*********************************************************
-%* *