[Haskell-cafe] Re: [darcs-users] Poll: Do you need to be able to build darcs from source on GHC 6.6?
On Thu, Oct 30, 2008 at 01:30:51PM -0700, Jason Dagit wrote: On Thu, Oct 30, 2008 at 1:22 PM, Juliusz Chroboczek [EMAIL PROTECTED] wrote: Also, note that Lenny has 6.8, and it is scheduled to become stable Real Soon Now. That's irrelevant. Lenny going stable will not cause my servers to automatically get upgraded. FWIW, the experimental server is scheduled to switch to lenny in the summer of 2009. There is no ETA for the production servers, which tend to be managed more conservatively still. But surely if you have such conservative upgrade practices you also only run stable releases of darcs right? All the existing stable releases build on ghc6.6. I was not sufficiently clear in my original question. My question really only applies to people who build from the darcs.net respository. HEAD as some people might call it. No, darcs is buggier than the average code, and it's reasonable to want those bugs fixed, even on stable servers. David ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [darcs-users] Poll: Do you need to be able to build darcs from source on GHC 6.6?
On Thu, Oct 30, 2008 at 03:08:29PM -0700, Don Stewart wrote: dagit: On Thu, Oct 30, 2008 at 1:20 PM, Juliusz Chroboczek [EMAIL PROTECTED] wrote: I wanted to know if anyone who is using distros with 6.6 need to be able to build current releases of darcs from source. If there turns out to be a significant issue with Darcs 1, I need to be able to build a recent version of Darcs in my Debian stable chroot. I see. If you're using the darcs 1 binary I would encourage you to upgrade. If you meant darcs 1 repository format then I would encourage you to consider darcs 1 hashed repository format. You don't even have to upgrade the public facing repo. Just 'darcs get --hashed ...'. The alternative is to build a static version of Darcs that I can install on my stable (soon to be oldstable) servers. Last time I checked, building static Darcs didn't work. Interesting. Yes, building darcs statically is something we should probably do on the build bots. Statically linked darcs should be trivial with the cabal version. The bug is in debian's libcurl. David ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cairo build fail on OS X Leapord
Installing gtk2hs from MacPorts on a clean mac: 2 -I/usr/X11R6/include svgcairo/Graphics/Rendering/Cairo/SVG.chs:201:2: Couldn't match expected type `()' against inferred type `CInt' Expected type: Render () Inferred type: Render CInt In the expression: liftIO $ (\ (SVG arg1) (Cairo arg2) - withForeignPtr arg1 $ \ argPtr1 - rsvg_handle_render_cairo argPtr1 arg2) svg cr In the expression: do cr - ask liftIO $ (\ (SVG arg1) (Cairo arg2) - withForeignPtr arg1 $ \ argPtr1 - rsvg_handle_render_cairo argPtr1 arg2) svg cr make[1]: *** [svgcairo/Graphics/Rendering/Cairo/SVG.o] Error 1 rm svgcairo/Graphics/Rendering/Cairo/SVG.hs make: *** [all] Error 2 Error: Status 1 encountered during processing. -- I try to take things like a crow; war and chaos don't always ruin a picnic, they just mean you have to be careful what you swallow. -- Jessica Edwards ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Newbie on instance of Monad
Hi, After a lot of thinking, I can't get what I am doing wrong in this code: -- data ( RandomGen g ) = RandomMonad g a = RandomMonad (g - a) instance Monad (RandomMonad g) where return = RandomMonad . const RandomMonad f1 = f2 = RandomMonad f3 where f3 a = f2f1 a (next a) RandomMonad f2f1 = f2 . f1 -- I get this error message: Could not deduce (RandomGen g) from the context (Monad (RandomMonad g)) arising from a use of `RandomMonad' at src/encherDB.hs:10:11-21 Possible fix: add (RandomGen g) to the context of the type signature for `return' In the first argument of `(.)', namely `RandomMonad' In the expression: RandomMonad . const In the definition of `return': return = RandomMonad . const but I'm not smart enough to understand what it means. Thanks a lot, MaurÃcio ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie on instance of Monad
On Fri, 31 Oct 2008, Mauricio wrote: Hi, After a lot of thinking, I can't get what I am doing wrong in this code: -- data ( RandomGen g ) = RandomMonad g a = RandomMonad (g - a) RandomGen g is considered the constraint for the application of RandomMonad constructor, but GHC does not conclude that every value of (RandomMonad g a) fulfills this constraint. Actually, 'undefined' is available for any 'g'. instance Monad (RandomMonad g) where return = RandomMonad . const RandomMonad f1 = f2 = RandomMonad f3 where f3 a = f2f1 a (next a) RandomMonad f2f1 = f2 . f1 you need to make (RandomGen g) a constraint of the instance: instance RandomGen g = Monad (RandomMonad g) where Btw. RandomMonad looks like Control.Monad.Reader. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie on instance of Monad
On Fri, 31 Oct 2008, Jonathan Cast wrote: On Fri, 2008-10-31 at 18:43 -0200, Mauricio wrote: Hi, After a lot of thinking, I can't get what I am doing wrong in this code: -- data ( RandomGen g ) = RandomMonad g a = RandomMonad (g - a) instance Monad (RandomMonad g) where return = RandomMonad . const RandomMonad f1 = f2 = RandomMonad f3 where f3 a = f2f1 a (next a) RandomMonad f2f1 = f2 . f1 Yikes. Just search the archives for `Set not a Monad'; you have the same issue. I think that this would be the answer if he is after a constraint for 'a', but he wants to constraint 'g'. Hint: data RandomGen g = RandomMonad g a means nothing at all like what you think it means. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Newbie on instance of Monad
On Fri, 2008-10-31 at 18:43 -0200, Mauricio wrote: Hi, After a lot of thinking, I can't get what I am doing wrong in this code: -- data ( RandomGen g ) = RandomMonad g a = RandomMonad (g - a) instance Monad (RandomMonad g) where return = RandomMonad . const RandomMonad f1 = f2 = RandomMonad f3 where f3 a = f2f1 a (next a) RandomMonad f2f1 = f2 . f1 -- I get this error message: Could not deduce (RandomGen g) from the context (Monad (RandomMonad g)) arising from a use of `RandomMonad' at src/encherDB.hs:10:11-21 Possible fix: add (RandomGen g) to the context of the type signature for `return' In the first argument of `(.)', namely `RandomMonad' In the expression: RandomMonad . const In the definition of `return': return = RandomMonad . const but I'm not smart enough to understand what it means. Yikes. Just search the archives for `Set not a Monad'; you have the same issue. Hint: data RandomGen g = RandomMonad g a means nothing at all like what you think it means. jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] darcs hacking sprint #1 (report)
Dear Haskellers, I thought some of you might be interested in our report from the darcs hacking sprint, held on 25-26 October. See also the blog version of it at http://blog.darcs.net/2008/10/darcs-hacking-sprint-1-report.html (it has photos). So how did that darcs hacking sprint go? Well, we had a lot of fun and we got a lot of work done, so I think we can safely say that it was a great success! What next? The sprint participants found themselves with a lot of good work started that we simply couldn't put down, so we have continued hacking into the week, turning many of our good starts into more concrete progress. There is still a lot of work to do so we want to make sure we keep that momentum going! The big challenge right now is to get all of the patches reviewed and merged back into darcs.net. Unfortunately, this is creating a delay in the usual patch review process as we clear our backlog. In the meantime, please continue sending your patches! Thanks very much to David Roundy for his advice before the sprint and cheerful handling of this patch influx; Galois, the University of Brighton and Université de Paris 7 for graciously hosting our three venues; and especially to everybody who participated or joined #darcs to cheer us on :-) The next sprint will be held in conjunction with the Haskell Hackathon, March 2009 in Utrecht, Netherlands. So see you in six months! Overview Total sprint patches: 234 Patches produced - during the sprint itself : 178 - as follow-up work: 56 Patches sent and - accepted into darcs.net : 43 - awaiting review : 191 (during defined as 25-27 October 2008 at 08:00 UTC) Site reports * Team Portland: - report: http://lists.osuosl.org/pipermail/darcs-users/2008-October/015082.html - pictures: http://blog.codersbase.com/2008/10/28/darcs-hacking-sprint-summary-from-portland-team/ * Team Brighton: - report: http://lists.osuosl.org/pipermail/darcs-users/2008-October/015122.html - pictures: http://koweycode.blogspot.com/2008/10/darcs-hacking-sprints-some-pictures.html - pictures: http://koweycode.blogspot.com/2008/10/darcs-hacking-sprint-team-brighton-day.html * Team Paris: - report: http://lists.osuosl.org/pipermail/darcs-users/2008-October/015215.html What we worked on - Warm up tasks = * Warn the user when the patch name looks like a command line option - http://bugs.darcs.net/issue395 - Participants: Reinier Lamers (Team Paris) - Status: Accepted! * Warn when tags are too short (length name 2) - http://bugs.darcs.net/issue1000 - Participants: Christian Kellerman - Status: Accepted! Optimisations = * Solved stack overflow when doing whatsnew on very large lines - http://bugs.darcs.net/issue1017 - Participants: Ganesh Sittampalam (Team Brighton) - Status: awaiting review * Smarter slurpies for faster directory lookups - http://bugs.darcs.net/issue711 - Participants: Ganesh Sittampalam (Team Brighton) - Status: awaiting review * Avoiding lstats in darcs whatsnew - http://bugs.darcs.net/issue390 - Participants: Reinier Lamers (Team Paris) - Status: needs tweaking * Bytestring optimisations - Participants: Don Stewart (Team Portland) - Status: awaiting review Performance-related features * Filecache to improve darcs annotate and darcs changes performance - Participants: Benedikt Schmidt - Status: still hacking! * Packs - http://wiki.darcs.net/index.html/Packs_Specification - Participants: Nicolas Pouillard, Florent Becker (Team Paris) - Status: plan is fleshed out; implementation started in branch * Chunky hunk representation - Participants: Ian Lynagh (Team Brighton) - Status: needs volunteer to start porting from camp to darcs * Global cache: enabled by default and more portable - http://bugs.darcs.net/issue839 - Participants: Simon Michael - Status: Accepted! * Networking performance (Team Paris) - Used tcpdump to examine network performance problems - New issues filed: * http://bugs.darcs.net/issue1167 - darcs-transfer mode versions * http://bugs.darcs.net/issue1168 - ssh pipelining * http://bugs.darcs.net/issue1170 - Nagle's algorithm - Participants: Team Paris - Status: needs implementation! Improved Windows support * Bugs fixed: - newline endings on Windows for HTTP module. - http://bugs.darcs.net/issue774 - fix character echo on win32. - http://bugs.darcs.net/issue1023 - bracket file writing to prevent windows permission errors. - http://bugs.darcs.net/issue784 - fix file handle leak and check for exceptions on process running. * Participants: Salvatore Insalaco * Status: Accepted! Infrastructure and cleanups === * Code cleanups - Added language pragmas in all files - Removed OldFastPackedString - Replaced FastPackedStrings api in
Re: [Haskell-cafe] Re: Why 'round' does not just round numbers ?
On Oct 30, 2008, at 5:21 PM, Bertram Felgenhauer wrote: George Pollard wrote: There's also the ieee-utils package, which provides an IEEE monad with `setRound`: http://hackage.haskell.org/packages/archive/ieee-utils/0.4.0/doc/ html/Numeric-IEEE-RoundMode.html When run with +RTS -N2 -RTS, the output randomly alternates between Downward and ToNearest - for me at least. The problem is that the setRound call will only affect one worker thread, while the RTS will sometimes migrate RTS threads from one worker to another. runIEEE really has to be executed in a bound thread (see forkOS documentation). Using `par` will also cause trouble - in fact even more. That's a really nice catch! Dons has pointed out to me both the very handy forkOnIO which ensures the forked thread remains bound to a single CPU, and also the -qm flag to the RTS, which prevents thread migration between capabilities. Running the example program with +RTS -N2 -qm restores the behavior to what's intended. I'll try to get around to changing the documentation to reflect this. Also, it's worth noting that the IEEE round mode has no effect on rounding done with the `round` function, as that's explicitly coded to provide the behavior seen in the report. Regards, Sterl. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
