On Mon, Jul 11, 2011 at 6:27 PM, Michael Orlitzky <mich...@orlitzky.com> wrote: > On 07/10/11 15:37, Felipe Almeida Lessa wrote: >> You don't need to do it, it is already done =). See the pool >> package by Michael Snoyman on Hackage [1]. More specifically, see >> createPoolCheckAlive [2]. >> >> Cheers, >> >> [1] http://hackage.haskell.org/package/pool [2] >> http://hackage.haskell.org/packages/archive/pool/0.1.0.2/doc/html/Data-Pool.html#v:createPoolCheckAlive >> >> > > How do people use this stuff? The README is empty, there's no > documentation, and none of the functions are commented. I'm forced to > conclude that there are people capable of looking at this, > > createPoolCheckAlive :: MonadControlIO m > => IO a > -> (a -> IO ()) > -> Int > -> (Pool a -> m b) > -> (a -> IO Bool) > -> m b > > and knowing immediately what it does. > > I'm still a beginner, and I don't think I have a use for this package > (what does it do?), but I've run into similar situations with other > packages and would genuinely like to know (as opposed to just complain > about it). >
Author of the package speaking. I agree, that's a problem :). I've just uploaded a new version[1] that is properly documented, though it will take a bit for Hackage to generates the Haddocks. As Brandon said, the reason this wasn't documented in the first place is that it was an internally used module for Persistent that I decided after the fact to release separately. As for Bryan's resource-pool: currently I would strongly recommend *against* using it for any purpose. It is based on MonadCatchIO-transformers[2], which is a subtly broken package. In particular, when I tried using it for pool/persistent in the first place, I ended up with double-free bugs from SQLite. As an abridged history, I ended up writing a replacement called MonadInvertIO, which later was superceded by MonadPeelIO[3] and MonadControlIO[4]. The latter two packages are both much more correct that MonadCatchIO, and either one should be used in its place. I did email Bryan about this a bit ago, but he didn't get back (he *is* a very busy guy). Ideally, I think that we don't need to have both pool and resource-pool, but such is the situation right now. Michael [1] http://hackage.haskell.org/package/pool-0.1.0.3 [2] http://hackage.haskell.org/package/MonadCatchIO-transformers-0.2.2.2 [3] http://hackage.haskell.org/package/monad-peel [4] http://hackage.haskell.org/package/monad-control-0.2.0.1 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
