Re: RFC: Compiler plugins for GHC (was: Release/git plans)
On 23 January 2011 00:31, austin seipp a...@hacks.yi.org wrote: or what the current state of dynamic linking on windows is. AFAIK it is meant to work. What I'm not sure about is whether any of the plugins code will have to be modified to make use of it. I suspect it won't since IIRC I went through the GHCi symbol loading code, which should have been extended to load symbols from shared libraries just fine. There is also an issue about whether the GHC executable is statically linked to libGHC or not. If it is, then you need to build GHC with ---export-dynamic (on Windows/Linux - there is another flag on OS X) so libGHC symbols are exported from the GHC executable. This is essential because you want a loaded plugin to link against the shared data in a *running GHC*, not a new instance of it. With any luck, nowadays GHC dynamically links to libGHC, in which case this is all a non-issue. Cheers, Max ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
On 21 January 2011 23:59, austin seipp a...@hacks.yi.org wrote: Perhaps Max can elaborate on why this design was rejected in favor of the current one, so we can see how and where it falls down, and what we really want. The only reason really is that it added a lot of mechanism. From the top of my head: * Parsing etc for PHASE pragmas that declared phase objects * A new namespace for phases * Stuff to gather declared phases from all imported modules during compilation * A built-in phase for each core pass * A solver that ordered core passes and plugin passes according to the phases So it was a lot of trouble for relatively little gain. In an effort to keep the delta against GHC small I threw it out in favour of the much, much simpler design we have today. Thomas pointed out the Scala compiler plugin design document, so I'll be sure to read over it this weekend when I get the chance to cook up ideas. The Scala plugins project was just starting when I was working on GHC plugins so there was no design doc I could refer to at that time. Shame :-( Thanks for taking the lead on resurrecting plugins, Austin! Cheers, Max ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
Hi Austin, The compiler plugins work is a great, and I'd be a likely user. The original version wasn't supported on Windows, because GHC on Windows lacked various forms of dynamic linking. Does the current patch you've prepared work on Windows? Thanks, Neil On Sat, Jan 22, 2011 at 10:29 AM, Max Bolingbroke batterseapo...@hotmail.com wrote: On 21 January 2011 23:59, austin seipp a...@hacks.yi.org wrote: Perhaps Max can elaborate on why this design was rejected in favor of the current one, so we can see how and where it falls down, and what we really want. The only reason really is that it added a lot of mechanism. From the top of my head: * Parsing etc for PHASE pragmas that declared phase objects * A new namespace for phases * Stuff to gather declared phases from all imported modules during compilation * A built-in phase for each core pass * A solver that ordered core passes and plugin passes according to the phases So it was a lot of trouble for relatively little gain. In an effort to keep the delta against GHC small I threw it out in favour of the much, much simpler design we have today. Thomas pointed out the Scala compiler plugin design document, so I'll be sure to read over it this weekend when I get the chance to cook up ideas. The Scala plugins project was just starting when I was working on GHC plugins so there was no design doc I could refer to at that time. Shame :-( Thanks for taking the lead on resurrecting plugins, Austin! Cheers, Max ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RFC: Compiler plugins for GHC (was: Release/git plans)
(moved into g-h-u mainline to avoid cluttering discussion around new GHC plans. Anybody who has comments on the plugins work is encouraged to reply here, not there.) Neil, Preemptive TL;DR: I don't quite know, but I'd be willing to work on it. I seem to remember at the time Max originally did his work (2008,) dynamic linking outside of the home-grown linker inside GHCi (a rather ad-hoc, special-use linker) was not available for any platforms GHC supported. I wouldn't know what windows support lacked at the time it was initially written, and I'm not sure about the state of it now is the main thing I'm getting at I suppose. I didn't know enough about GHC at the time. If my memory serves correctly, Clemens Fruhwirth initally wrote the patches for dynamic linking as we know it for GHC in 2007, although they were only for linux. Later on, Simon M and Duncan Coutts did the remaining work to get it release-quality ready on linux sometime around when the new build system for GHC hit. I seem to remember Well-Typed LLC *also* doing work on also supporting that form of dynamic linking on windows. As a feature it seems to touch several parts of GHC for every supported platform, if it is to support the use-cases we would expect (like writing DLL/shared objects, or also having the compiler being able to dynamically link objects - like plugins.) I can't for the life of me remember if any of this work went into mainline GHC, or what the current state of dynamic linking on windows is. At this exact moment, I do not have a windows machine to test or develop GHC HEAD on - although we're in luck, as I should have a local windows instance to use as a personal machine within the week. I have only tested the patch on Linux and OS X Snow Leopard against GHC HEAD - I am honestly not even aware of what is necessary to build a development version of GHC on windows. But, I would be more than willing and happy to work on it and work with GHC HQ to support it if you're a potential user. I wouldn't want to shaft Windows users anyway. So, if anybody can point out how to get GHC development on windows up and running, I think I can point myself in the right direction. I'll be sure to get back to you on how things go, Neil. On Sat, Jan 22, 2011 at 11:20 AM, Neil Mitchell ndmitch...@gmail.com wrote: Hi Austin, The compiler plugins work is a great, and I'd be a likely user. The original version wasn't supported on Windows, because GHC on Windows lacked various forms of dynamic linking. Does the current patch you've prepared work on Windows? Thanks, Neil On Sat, Jan 22, 2011 at 10:29 AM, Max Bolingbroke batterseapo...@hotmail.com wrote: On 21 January 2011 23:59, austin seipp a...@hacks.yi.org wrote: Perhaps Max can elaborate on why this design was rejected in favor of the current one, so we can see how and where it falls down, and what we really want. The only reason really is that it added a lot of mechanism. From the top of my head: * Parsing etc for PHASE pragmas that declared phase objects * A new namespace for phases * Stuff to gather declared phases from all imported modules during compilation * A built-in phase for each core pass * A solver that ordered core passes and plugin passes according to the phases So it was a lot of trouble for relatively little gain. In an effort to keep the delta against GHC small I threw it out in favour of the much, much simpler design we have today. Thomas pointed out the Scala compiler plugin design document, so I'll be sure to read over it this weekend when I get the chance to cook up ideas. The Scala plugins project was just starting when I was working on GHC plugins so there was no design doc I could refer to at that time. Shame :-( Thanks for taking the lead on resurrecting plugins, Austin! Cheers, Max ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users -- Regards, Austin -- Regards, Austin ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: Release/git plans
Austin | So, given that 7.2 will be released much earlier than the normal | release cycle, is there any room for anything else to get into HEAD | for the 7.2 release before everything is switched? In particular I | fixed up Max Bolingbroke's old compiler plugin work to be usable with | the latest HEAD, and all the fundamental work is there and done, just | some additional small things are needed (notably having ghc dump | plugin information a la -ddump flags, and testsuite patches are about | it I think.) The patch itself is pretty small and doesn't touch *too* | much code, mostly adding dynamic loading and the plugin API, but it's | arguably adding a 'big' feature for users of GHC to start utilizing, | and perhaps a release in 7.2 would cause problems merging changes | until you cut a new STABLE branch with git, like you said. I'm sorry I've been slow on this. Review and apply the plugins patch is in my inbox, but it's been queued up behind too many other things, notably making the new typechecker work. I'm pretty keen on the whole plugin idea, because it makes the compiler more extensible and lowers the barrier to entry. My only reason for delay is that I wanted to review the design (as seen by a plug-in author). Once we provide it, we have to support it, and it's harder to change. The fact that you are actively engaged, have done the work with Max, and are (I assume) happy to respond to user queries, fix bugs etc, is a major incentive. Thank you! So yes, because of that I undertake to do this for 7.2 [unless Simon M tells me no :-)]. I'll add a few thoughts to the ticket right now. http://hackage.haskell.org/trac/ghc/ticket/3843. Interested parties, add yourselves to the cc list of the ticket. Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
On 21 January 2011 09:13, Simon Peyton-Jones simo...@microsoft.com wrote: I'm pretty keen on the whole plugin idea, because it makes the compiler more extensible and lowers the barrier to entry. My only reason for delay is that I wanted to review the design (as seen by a plug-in author). Once we provide it, we have to support it, and it's harder to change. The Scala compiler has a plugin system. Here's a document that describes their approach to dealing with phase ordering of plugins: http://www.scala-lang.org/sid/2. It seems rather complex, but seems necessary (or the document is just very long). There's also a tutorial on writing Scala plugins, which may help to get a feel for how their API works. http://www.scala-lang.org/node/140 / Thomas ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
Simon, On Fri, Jan 21, 2011 at 3:13 AM, Simon Peyton-Jones simo...@microsoft.com wrote: Austin | So, given that 7.2 will be released much earlier than the normal | release cycle, is there any room for anything else to get into HEAD | for the 7.2 release before everything is switched? In particular I | fixed up Max Bolingbroke's old compiler plugin work to be usable with | the latest HEAD, and all the fundamental work is there and done, just | some additional small things are needed (notably having ghc dump | plugin information a la -ddump flags, and testsuite patches are about | it I think.) The patch itself is pretty small and doesn't touch *too* | much code, mostly adding dynamic loading and the plugin API, but it's | arguably adding a 'big' feature for users of GHC to start utilizing, | and perhaps a release in 7.2 would cause problems merging changes | until you cut a new STABLE branch with git, like you said. I'm sorry I've been slow on this. Review and apply the plugins patch is in my inbox, but it's been queued up behind too many other things, notably making the new typechecker work. That's fine! One thing at a time. The typechecker overhaul is great IMO, and I've noticed it's fixed many strange GHC bugs relating to type system feature interactions (including a few I hit.) Much appreciated work! I'm pretty keen on the whole plugin idea, because it makes the compiler more extensible and lowers the barrier to entry. My only reason for delay is that I wanted to review the design (as seen by a plug-in author). Once we provide it, we have to support it, and it's harder to change. This is very reasonable and I was going to mention it once someone responded. Up to this point, Max has really been the main person to write any plugins for GHC using the current interface. I would really welcome anybody interested in hacking on GHC look at the current API in the patch - my main concern up to this point is that the actual means of installing passes into the Core pipeline, the installation function of type `[CoreToDo] - CoreM [CoreToDo]`, is a little fragile. Scala's approach seems to be to have plugins specify 'runAfter' and 'runBefore' constraints, which specify what compiler phases should run before and after the plugin's pass in question (and certain phases may run multiple times, so as a consequence, so does your plugin.) If I remember correctly, this was somewhat similar to the original design Max proposed which was to specify in which phase the pass is run, and it essentially amounted to a phase constraint. Perhaps Max can elaborate on why this design was rejected in favor of the current one, so we can see how and where it falls down, and what we really want. Thomas pointed out the Scala compiler plugin design document, so I'll be sure to read over it this weekend when I get the chance to cook up ideas. Also worth noting, like I said, is I would inevitably like to extend compiler plugins to work on Cmm, once the new codegen (using hoopl) hits. Maybe even allow you to write a new backend ultimately if you wanted to, although I'd call that the last and ultimate challenge at this point (because from my cursory glances, it would require quite a bit of re-engineering and re-design of the driver and compilation pipeline, much more so than just the Core plugins did or Cmm plugins might. That's a bit more time than I have... at the moment ;) To accumulate ideas and comments I've spent the past few days writing up a wiki page (mostly written in the wee hours of the morning no less), documenting the current API, how it might be improved, and future work like C-- plugins or plugins implementing new backends. Most of it is half baked. And half-written. Probably grammatical errors and run-on sentences. Incomplete sections. Likely with big, stupid ideas. Caveat emptor, etc. The wiki page in all its (horrid, half-written and mangled) glory can be located here: http://hackage.haskell.org/trac/ghc/wiki/NewPlugins If people can comment and add ideas, it will be much easier to determine if this should go into 7.2.1. If the current API is too fragile or needs to be expanded, it would likely be best to back out and do some work, and try again for 7.4.1. That will also give a much bigger window for feedback and testing, since 7.2 will be on a much shorter cycle it seems. I'll probably end up throwing up a RFC on both glasgow-haskell-users and cvs-ghc sometime in the next week to get feedback after more brainstorming, because it's the most important thing as of right now and for any future work in this area, in my opinion, since it will be a publicly exposed API for users to write code against. The fact that you are actively engaged, have done the work with Max, and are (I assume) happy to respond to user queries, fix bugs etc, is a major incentive. Thank you! I'm more than happy to respond to any user queries and respond to bugs people come up with, yes (Max seems to be working
Re: Release/git plans
Llvm is also a good reference for compiler plugin design; it would appear that Scala borrowed from their approach. -scooter Sent from my Verizon Wireless BlackBerry -Original Message- From: austin seipp a...@hacks.yi.org Sender: glasgow-haskell-users-boun...@haskell.org Date: Fri, 21 Jan 2011 17:59:32 To: Simon Peyton-Jonessimo...@microsoft.com Cc: Simon Marlowmarlo...@gmail.com; glasgow-haskell-users@haskell.orgglasgow-haskell-users@haskell.org Subject: Re: Release/git plans Simon, On Fri, Jan 21, 2011 at 3:13 AM, Simon Peyton-Jones simo...@microsoft.com wrote: Austin | So, given that 7.2 will be released much earlier than the normal | release cycle, is there any room for anything else to get into HEAD | for the 7.2 release before everything is switched? In particular I | fixed up Max Bolingbroke's old compiler plugin work to be usable with | the latest HEAD, and all the fundamental work is there and done, just | some additional small things are needed (notably having ghc dump | plugin information a la -ddump flags, and testsuite patches are about | it I think.) The patch itself is pretty small and doesn't touch *too* | much code, mostly adding dynamic loading and the plugin API, but it's | arguably adding a 'big' feature for users of GHC to start utilizing, | and perhaps a release in 7.2 would cause problems merging changes | until you cut a new STABLE branch with git, like you said. I'm sorry I've been slow on this. Review and apply the plugins patch is in my inbox, but it's been queued up behind too many other things, notably making the new typechecker work. That's fine! One thing at a time. The typechecker overhaul is great IMO, and I've noticed it's fixed many strange GHC bugs relating to type system feature interactions (including a few I hit.) Much appreciated work! I'm pretty keen on the whole plugin idea, because it makes the compiler more extensible and lowers the barrier to entry. My only reason for delay is that I wanted to review the design (as seen by a plug-in author). Once we provide it, we have to support it, and it's harder to change. This is very reasonable and I was going to mention it once someone responded. Up to this point, Max has really been the main person to write any plugins for GHC using the current interface. I would really welcome anybody interested in hacking on GHC look at the current API in the patch - my main concern up to this point is that the actual means of installing passes into the Core pipeline, the installation function of type `[CoreToDo] - CoreM [CoreToDo]`, is a little fragile. Scala's approach seems to be to have plugins specify 'runAfter' and 'runBefore' constraints, which specify what compiler phases should run before and after the plugin's pass in question (and certain phases may run multiple times, so as a consequence, so does your plugin.) If I remember correctly, this was somewhat similar to the original design Max proposed which was to specify in which phase the pass is run, and it essentially amounted to a phase constraint. Perhaps Max can elaborate on why this design was rejected in favor of the current one, so we can see how and where it falls down, and what we really want. Thomas pointed out the Scala compiler plugin design document, so I'll be sure to read over it this weekend when I get the chance to cook up ideas. Also worth noting, like I said, is I would inevitably like to extend compiler plugins to work on Cmm, once the new codegen (using hoopl) hits. Maybe even allow you to write a new backend ultimately if you wanted to, although I'd call that the last and ultimate challenge at this point (because from my cursory glances, it would require quite a bit of re-engineering and re-design of the driver and compilation pipeline, much more so than just the Core plugins did or Cmm plugins might. That's a bit more time than I have... at the moment ;) To accumulate ideas and comments I've spent the past few days writing up a wiki page (mostly written in the wee hours of the morning no less), documenting the current API, how it might be improved, and future work like C-- plugins or plugins implementing new backends. Most of it is half baked. And half-written. Probably grammatical errors and run-on sentences. Incomplete sections. Likely with big, stupid ideas. Caveat emptor, etc. The wiki page in all its (horrid, half-written and mangled) glory can be located here: http://hackage.haskell.org/trac/ghc/wiki/NewPlugins If people can comment and add ideas, it will be much easier to determine if this should go into 7.2.1. If the current API is too fragile or needs to be expanded, it would likely be best to back out and do some work, and try again for 7.4.1. That will also give a much bigger window for feedback and testing, since 7.2 will be on a much shorter cycle it seems. I'll probably end up throwing up a RFC on both glasgow-haskell-users and cvs-ghc sometime in the next week to get feedback after
Release/git plans
As promised, here are our plans for forthcoming GHC releases and the git switchover: - do a 7.0.2 RC as soon as possible, followed shortly by a release. Currently blocking this is a problem with Cabal that shows up on OS X 10.6, we hope to have this resolved soon. - switch the GHC repo to git (this is ready to go, we just need to flip the switch and do some work on the wiki build documentation) - switch the libraries and other repositories to git, once we have decided on the strategy (mirror or convert) for each one. - make a new stable branch for 7.2, and release 7.2.1 shortly after. So we'll be doing a 7.2.1 release much earlier than planned. Our motivation for doing this is: - the 7.0 branch is darcs, but the HEAD will be git, so the longer this situation persists the more difficult it is to merge changes. Hence we want to fork a new STABLE branch as soon as possible. - one of the fixes we need to make soon, to fix equality superclasses, is too large a change to put in the 7.0 branch. We also have some pending changes to the internal representation of coercions that will be disruptive in HEAD, and will make future merging to 7.0 difficult. - 7.0.2 should be a nice stable release, and HEAD is actually in pretty good shape right now too. FYI, the git repo is now attached to our Trac instance, so you can browse the source tree and history here: http://hackage.haskell.org/trac/ghc/browser it's not terribly fast, but it works. With git we'll be able to link directly to commits from tickets and vice-versa. The GHC git repo that we'll be using is here: http://darcs.haskell.org/ghc.git (note different from the URL for the testing repo, although it's the same repo). I'm mirroring this manually from the darcs repo, so it might lag a bit at times. Cheers, Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
Hello Simon, On Thu, Jan 20, 2011 at 9:48 AM, Simon Marlow marlo...@gmail.com wrote: ... - make a new stable branch for 7.2, and release 7.2.1 shortly after. So we'll be doing a 7.2.1 release much earlier than planned. Our motivation for doing this is: - the 7.0 branch is darcs, but the HEAD will be git, so the longer this situation persists the more difficult it is to merge changes. Hence we want to fork a new STABLE branch as soon as possible. - one of the fixes we need to make soon, to fix equality superclasses, is too large a change to put in the 7.0 branch. We also have some pending changes to the internal representation of coercions that will be disruptive in HEAD, and will make future merging to 7.0 difficult. - 7.0.2 should be a nice stable release, and HEAD is actually in pretty good shape right now too. So, given that 7.2 will be released much earlier than the normal release cycle, is there any room for anything else to get into HEAD for the 7.2 release before everything is switched? In particular I fixed up Max Bolingbroke's old compiler plugin work to be usable with the latest HEAD, and all the fundamental work is there and done, just some additional small things are needed (notably having ghc dump plugin information a la -ddump flags, and testsuite patches are about it I think.) The patch itself is pretty small and doesn't touch *too* much code, mostly adding dynamic loading and the plugin API, but it's arguably adding a 'big' feature for users of GHC to start utilizing, and perhaps a release in 7.2 would cause problems merging changes until you cut a new STABLE branch with git, like you said. It would be nice to have this in GHC 7.2, but I was thinking of eventually extending the scope of compiler plugins to allow users to write Cmm optimisations as well. It would likely be best to wait for the switch to Git and for the new code generator branch to be merged before that work happens though, but writing plugins that do Core passes seem to work well right now. The GHC git repo that we'll be using is here: http://darcs.haskell.org/ghc.git This is an incredibly minor note in my opinion (that was brought up before IIRC) but, isn't it a little strange for ghc's git repository to exist on darcs.haskell.org? Not that it's a problem, just slightly confusing I guess. -- Regards, Austin ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
On 20 January 2011 16:57, austin seipp a...@hacks.yi.org wrote: It would be nice to have this in GHC 7.2, but I was thinking of eventually extending the scope of compiler plugins to allow users to write Cmm optimisations as well. This would be particularly cool because Cmm optimisations in the new Hoopl framework compose extremely nicely. (And yes, obviously I would be very happy if Simon commits my plugins patches ;-)) Max ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
On 01/20/11 11:57, austin seipp wrote: The GHC git repo that we'll be using is here: http://darcs.haskell.org/ghc.git This is an incredibly minor note in my opinion (that was brought up before IIRC) but, isn't it a little strange for ghc's git repository to exist on darcs.haskell.org? Not that it's a problem, just slightly confusing I guess. Yes, and the commits mailing-list is still called cvs-...@haskell.org. The niceness of sounding right tends to be outweighed by the inconvenience of switching :) -Isaac ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
Point taken, I personally think it's rather minor although it was brought up before like I said, so perhaps others think differently. Either way, I, for one, welcome our new version control overlord. On Thu, Jan 20, 2011 at 3:09 PM, Isaac Dupree m...@isaac.cedarswampstudios.org wrote: On 01/20/11 11:57, austin seipp wrote: The GHC git repo that we'll be using is here: http://darcs.haskell.org/ghc.git This is an incredibly minor note in my opinion (that was brought up before IIRC) but, isn't it a little strange for ghc's git repository to exist on darcs.haskell.org? Not that it's a problem, just slightly confusing I guess. Yes, and the commits mailing-list is still called cvs-...@haskell.org. The niceness of sounding right tends to be outweighed by the inconvenience of switching :) -Isaac ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users -- Regards, Austin ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Release/git plans
This is Haskell. One should abstract away the system used. Call it vcs-ghc@ and vcs.haskell.org ;-) Gruss, Christian * austin seipp a...@hacks.yi.org [20.01.2011 22:19]: Point taken, I personally think it's rather minor although it was brought up before like I said, so perhaps others think differently. Either way, I, for one, welcome our new version control overlord. On Thu, Jan 20, 2011 at 3:09 PM, Isaac Dupree m...@isaac.cedarswampstudios.org wrote: On 01/20/11 11:57, austin seipp wrote: The GHC git repo that we'll be using is here: http://darcs.haskell.org/ghc.git This is an incredibly minor note in my opinion (that was brought up before IIRC) but, isn't it a little strange for ghc's git repository to exist on darcs.haskell.org? Not that it's a problem, just slightly confusing I guess. Yes, and the commits mailing-list is still called cvs-...@haskell.org. The niceness of sounding right tends to be outweighed by the inconvenience of switching :) -Isaac ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users -- Regards, Austin ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users pgpncMFW5zZsL.pgp Description: PGP signature ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users