I'd like to emphasize that "bracket" is only one of multiple functions that needs to be changed. Some of those that need to be changed are primops.

On Thu, Nov 13, 2014 at 9:47 AM, Merijn Verstraaten <merijn@inconsistent.nl> wrote:

> On 12 Nov 2014, at 23:33, Bardur Arantsson <spam@scientician.net> wrote:
>
> Is the code for this available for inspection somewhere? (I realize it
> might change based on the outcome of this "poll", but...)

There's no complete patch, but I believe the outline has been sketched before, anyway to repeat it. The current implementation of bracket is as follows:

bracket
        :: IO a
        -> (a -> IO b)
        -> (a -> IO c)
        -> IO c
bracket before after thing =
  mask $ \restore -> do
    a <- before
    r <- restore (thing a) `onException` after a
    _ <- after a
    return r

A new version would look like:

bracket before after thing =
  mask $ \restore -> do
    let atomicAfter = uninterruptibleMask . after
    a <- before
    r <- restore (thing a) `onException` atomicAfter a
    _ <- atomicAfter a
    return r

Slightly different versions are possible and the other relevant bracketing functions mentioned in this thread can be treated similarly.

Cheers,
Merijn
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Eyal