Hi, So for those of you that watch the hackage what's-new page, you will probably be aware of this. For the last few months, there's been significant work on my implementation of Session Types in Haskell.[0] The reason for this particular announcement is that it should now be at a point where functionality is verging on useful. There are a few things that are still missing which should appear over the next few weeks but if you're at all interested in message-passing as a tool in the box for dealing with concurrency, I'd love to know what you think. To that end, I would *not* encourage you to try to look at the implementation too closely as you may suddenly discover a powerful urge to stick knives in your eyes and/or eat your computer. However, the Tests.hs[1] file should give you a good idea of the kinds of things that are possible and they do cover all the functionality currently implemented. Note that ghci may well take about 5 mins to type check Tests.hs. Or longer if you're still running a BBC B Micro. I would almost certainly not advise anyone to look at the haddock[2]. I really can't quite believe how horrible the type sigs end up looking under haddock. Some of my comments may almost pass the barrier of being useful. Nicely formatted type sigs exist in the source. If however, you are as mad as I, and enjoy pushing the GHC type system to the limit, then you may enjoy looking at the implementation in all its glory. base10 numbers, lists, associative maps and a whole lot of other madness works correctly at the type-level in ghc 6.8.2. Anyway, as the subject says, comments gratefully received. [0] http://hackage.haskell.org/cgi-bin/hackage-scripts/package/sessions-2008.2.2... [1] http://wellquite.org/non-blog/sessions-browseable/Control/Concurrent/Session... [2] http://wellquite.org/non-blog/sessions-browseable/doc/html/sessions/ [3] http://wellquite.org/non-blog/sessions-browseable/ Matthew -- Matthew Sackman http://www.wellquite.org/