Re: [Haskell-cafe] an array of pointers in FFI?
2008/8/1 Galchin, Vasili [EMAIL PROTECTED]: Thanks Bulat! So since we are talking ;^) is there a function already in Foreign that will allow me to ... [a] - Ptr (Ptr ()) i.e. map a list of type a to an array of ptrs of type a? I think this is going to be a two-part operation: first you'll need to store those values somewhere, so that you can produce pointers to them. Then, you create a (foreign) array and fill it with the pointers you got from step one. Of course, you'll need to manage memory for the two stages separately, ensuring that the pointers don't outlive the things they point to, and that both memory regions are freed when no longer needed. For example, if you have a list (xs :: [Int]), you can probably achieve the first step using (mapM new xs),* which should give you a list (ps:: [Ptr Int]). Then, you can do (newArray ps), which will allocate an array and store the pointers in it, giving you a pointer of type (Ptr (Ptr Int)). Once you're done, use (free) to clean up the array of pointers, and also each of the individual elements of (ps). If you only need the pointer array in a particular scope, you should be able to make your life a bit easier using the (alloca) or (with) family of functions. * This is probably a bit wasteful, since it makes a separate allocation for each element, but it does make life easier. Hope this helps. Stuart ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] a really dumb posting question ;^(
2008/7/31 Galchin, Vasili [EMAIL PROTECTED]: Hello, What do I do to do a followup haskell cafe posting? E.g. I want to put a posting on the category theory thread! You respond to it. Sometimes it is not sufficient (haskell-cafe@haskell.org isn't in the to or cc field), then you probably have a respond to all action in your mailer, you should use it. The best way is to use respond to list if you have it but respond to all should work properly. -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: category theory tutorial pdfs .....
On Fri, 1 Aug 2008 00:52:41 -0500, Galchin, Vasili [EMAIL PROTECTED] wrote: Hello, Prof. Harold Simmons' tutorial IMO are like a Russian matroshka doll ... first layer is for newbie ... inner layers require more sophistication. IMO a very subtle writer ... I have every book imaginable on cat theory and topos theory so I think can compare a little. 1) http://www.cs.man.ac.uk/~hsimmons/BOOKS/books.html ... an earlier version ... An Intro to Category Theory in Four Easy Movements ... this version delves a little into Topos Theory ... pretty subtle .. cool I have started reading _An introduction to category theory in four easy movements_ (see http://www.cs.man.ac.uk/~hsimmons/BOOKS/CatTheory.pdf). The author's style is very strange; in the first section, he states that he highlights subsidiary notions to be defined later in small caps, and even uses some of these in his exercises. For example, he highlights and uses preset and monoid as part of Exercise 1.1 before defining them, so I then need to hunt around in the vicinity for definitions (available several pages later). However, the PDF file is not text-searchable, so I need to hunt manually through the vicinity of pages to find a definition. This makes the book more interesting, at the expense of being harder to use. Do you know of a text-searchable version of this file? He also has a rather peculiar sense of humor. For instance, on page 6, he writes (regarding that in the original examples of categories, the arrows were morphisms which were then called homomorphism, and it wasn't realized that this family could be very large), (Some out and out category theorists still don't realize the significance of this. On the other hand, some off the wall set theorists don't realize the significance of category theory.) This reminds me of a lecture by David Gelernter in 1992 in a survey course on cognitive science at Yale in which he said that some weak AI cognitive scientists had said that other strong AI cognitive scientists must have been out to lunch. Again, if you know of a text-searchable version of this book, please post the reference in this thread. -- Benjamin L. Russell ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal files on Windows
On Sun, 2008-07-27 at 21:01 -0500, John Lato wrote: Use Haskell String syntax for paths that contain spaces: include-dirs: C:\\Program Files\\program\\include Hi Duncan, Thanks, this worked (mostly). Although I had to change the line to include-dirs: \C:\\Program Files\\program\\include\ so that the path would be passed properly to cpp through c2hs. Thanks for for filing the ticket John. http://hackage.haskell.org/trac/hackage/ticket/316#comment:1 Turns out Cabal is doing it right and it's c2hs that we need to fix. Shouldn't be too hard. Just need to change the way c2hs invokes cpp in Main.hs: let cmd = unwords [cpp, cppOpts, newHeaderFile, ++ preprocFile] tracePreproc cmd exitCode - liftIO $ system cmd to something like: let args = cppOpts ++ [newHeaderFile] tracePreproc (unwords (cmd : args)) exitCode - liftIO $ do preprocHnd - openFile WriteMode preprocFile process - runProcess cpp args Nothing Nothing Nothing (Just preprocHnd) Nothing waitForProcess process Try that, tell me if it works and we can add the patch to the c2hs repo. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Analysing Haskell Program
Hello to everybody I'm using haskell for some research work and now i need to evaluate the performance of some simple haskell programs in particular information on the like, CPU cycles, bus usage, memory access and so on; so i wish to know if there is a way to compile haskell programms so they can be used with simplescalar or if there is another tool which i can use. Thank you ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Analysing Haskell Program
On 1 Aug 2008, at 16:01, Roberto D'Aprile wrote: Hello to everybody I'm using haskell for some research work and now i need to evaluate the performance of some simple haskell programs in particular information on the like, CPU cycles, bus usage, memory access and so on; so i wish to know if there is a way to compile haskell programms so they can be used with simplescalar or if there is another tool which i can use. I've been getting some useful information by compiling with -fvia-C and then using dtrace to look at what's going on. Bob ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] poll: how can we help you contribute to darcs?
Dear Haskellers, I would like to take an informal poll for the purposes of darcs recruitment. Could you please complete this sentence for me? I would contribute to darcs if only... The answers I am most interested in hearing go beyond ... I had more time. For instance, if you are contributing to other Haskell/volunteer projects, why are you contributing more to them, rather than darcs? The context: Lately, darcs has suffered a setback: the GHC team has decided that it is now time to switch to a different system, like git or Mercurial. This is probably a good thing for GHC and for us. By the way, good luck to them, and thanks for everything! (better GHC == better darcs) But where is darcs going? For now, we are going to have to focus on what we do best, providing precision merging and a consistent user interface for small-to-medium sized projects. I want more, though! I want to see darcs 2.1 come out next year, performance enhanced out the wazoo, and running great on Windows. And I want to see Future Darcs, the universal revision control system, seamlessly integrating with everybody else. We need to learn to do better so that darcs can achieve this kind of wild success. For example, whereas darcs suffers from the day job problem, xmonad has had to turn developers away! As Don mentions, this is partly thanks to their extreme accessibility (better self-documentation). But does anyone have more specific ideas about things we need to change so that you can contribute to darcs? How do we hit critical hacker mass? I have jotted down some other thoughts here regarding recruitment here: http://wiki.darcs.net/index.html/Recruitment In the meantime, if you have been discouraged from hacking on darcs, we want to know why, and how we can change things! Thanks, ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [darcs-users] poll: how can we help you contribute to darcs?
I would contribute to darcs if only It didn't already do exactly what I want it to. As you've said darcs is really good for small-to-medium sized projects, particularly with few developers. Those are exactly the projects I happen to be working on. For my work I use darcs on a slightly larger project but with (mainly) only one developer (me). So basically because darcs works perfectly for me I have pretty little motivation to dive into the source code and 'fix' something which for me simply isn't broken. regards allan Eric Kow wrote: Dear Haskellers, I would like to take an informal poll for the purposes of darcs recruitment. Could you please complete this sentence for me? I would contribute to darcs if only... The answers I am most interested in hearing go beyond ... I had more time. For instance, if you are contributing to other Haskell/volunteer projects, why are you contributing more to them, rather than darcs? -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] HDBC-ODBC linking problems in windows.
Greetings everyone, I am having issues getting hdbc/odbc working on windows. When using GHC, I am not able to compile a simple program. It ends up with linker errors like C:\Program Files\Haskell\HDBC-odbc-1.1.4.3\ghc-6.8.3/libHSHDBC-odbc-1.1.4.3.a(Connection.o)(.text+0x52c):fake: undefined reference to `SQLAllocHandle' C:\Program Files\Haskell\HDBC-odbc-1.1.4.3\ghc-6.8.3/libHSHDBC-odbc-1.1.4.3.a(Connection.o)(.text+0x5b8):fake: undefined reference to `SQLSetEnvAttr' C:\Program Files\Haskell\HDBC-odbc-1.1.4.3\ghc-6.8.3/libHSHDBC-odbc-1.1.4.3.a(Connection.o)(.text+0x62c):fake: undefined reference to `SQLDriverConnect' C:\Program Files\Haskell\HDBC-odbc-1.1.4.3\ghc-6.8.3/libHSHDBC-odbc-1.1.4.3.a(Connection.o)(.text+0x700):fake: undefined reference to `SQLEndTran' C:\Program Files\Haskell\HDBC-odbc-1.1.4.3\ghc-6.8.3/libHSHDBC-odbc-1.1.4.3.a(Connection.o)(.text+0x770):fake: undefined reference to `SQLGetInfo' C:\Program Files\Haskell\HDBC-odbc-1 When I use ghci, it exits silently. It looks like calling convension mix-up in FFI declarations to me. I ran 'dumpbin' on odbc32.lib and all the exported function names are decorated like they are PASCAL calls, not ccall's. But GHC in this case is looking for undecorated names. I assume it works as is on Unix (unixODBC) ? Is there an easy workaround for this? Or am I doing something wrong? MySetup === Windows XP SP2 ghc 6.8.3 hdbc 1.1.5.0 hdbc-odbc 1.1.4.3.0 appreciate your time. Thanks pj ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] poll: how can we help you contribute to darcs?
I'd love to see a git-gui like interface to darcs. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] poll: how can we help you contribute to darcs?
On 2008 Aug 1, at 11:45, Eric Kow wrote: Dear Haskellers, I would like to take an informal poll for the purposes of darcs recruitment. Could you please complete this sentence for me? I would contribute to darcs if only... The darcs2 announcement strongly suggested that darcs would no longer be developed. This was brought up in the #ghc discussion about whether to switch. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] HDBC-ODBC linking problems in windows.
On Fri, Aug 1, 2008 at 11:09 AM, PJ Durai [EMAIL PROTECTED] wrote: Greetings everyone, I am having issues getting hdbc/odbc working on windows. When using GHC, I am not able to compile a simple program. It ends up with linker errors like I had similar issues buidling hdbc-postgres. I wrote up my experiences on their wiki - maybe it will help you. http://software.complete.org/software/wiki/16/WindowsInstall Justin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] poll: how can we help you contribute to darcs?
Eric Kow wrote: Dear Haskellers, I would like to take an informal poll for the purposes of darcs recruitment. Could you please complete this sentence for me? I would contribute to darcs if only... The answers I am most interested in hearing go beyond ... I had more time. For instance, if you are contributing to other Haskell/volunteer projects, why are you contributing more to them, rather than darcs? ...I knew how to help (and had the time). The You Too Can Hack on Darcs blog series is a really good idea. One problem many open-source projects suffer from is it not being apparent how a new hacker would even begin to start working. An overview of how the project is set up along with some notice about how malleable the different parts are goes a long way. It can also be helpful to take some RFI and walk through implementing the change, testing that it hasn't broken anything, and sending the patch (don't forget this step :). A follow on about getting ideas from the bug tracker is also good. Sometimes hands-on documentation is the best kind. Also documenting how a ninja developer could drop in, fix some things, and leave before anyone noticed is a good way to snare the folks who'd like to help a little but don't want to get dragged into being a regular developer (yet). Try-before-you-buy contributing is one of the best ways to get regular developers. ...I knew you needed help (and had the time). This is an image thing, but until the recent announcement of dayjob syndrome I was under the impression that darcs was rumbling along just fine. The wiki has a developers' FAQ and all, but the overall image is that darcs is stable and doing fine (and in my experience it is). Part of the reason I haven't contributed was that I've never thought about it-- and that's the problem. Silly as it sounds, even people who work on open-source code all the time don't always think about whether a project they use every day could use their support. And if it works just fine, they don't even have the impetus of wanting to fix it. I think it'd be good if the YTCHoD blog were more long lived than just something to gain developers now. A community blog for everyone hacking on darcs might help to demonstrate: (a) that there's a community of humans behind the software, [This is another thing that, silly as it sounds, people often forget about. For a humorous but all too true discussion of why, cf http://www.cracked.com/article_14990_what-monkeysphere.html.] (b) that they're nice folks who'd welcome new developers, [In the corporate world people will take a job for the money, but they stay (or leave) for the people. In open-source they may come for the code, but it's the community that keeps them around (or scares them off).] (c) and that there are specific tractable problems they have that non-developers could help with. [Bug trackers are an excellent source of tasks for active developers to use so things don't get lost, but they're awful for new developers. For someone just joining the project it's rarely clear how important a task is, how hard, or how far reaching its consequences (or whether someone's already working on it). Good trackers have fields to note these things, but the notes are engineered for active developers; the extent to which those notes are even used or accurate varies wildly from project to project. Hence, having a clear discussion about what things really are important and how much they interact with everything else is a great boon.] -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] poll: how can we help you contribute to darcs?
Hi I would contribute to darcs if only... The darcs2 announcement strongly suggested that darcs would no longer be developed. This was brought up in the #ghc discussion about whether to switch. I agree strongly with this. I would be much more likely to contribute if the project seemed active and alive. The darcs 2.0 announcement read like an obituary, and that put me off. The impression I came away with (accurate or not), was that the entire program had been rewritten, I was going to gain incompatibilities, and be using an untried/tested version which was not going to get any support. The message also seemed to be threatening me that if I didn't upgrade you would break into my house and wipe my data - instead of the usual enticement with cool new features :-) [Of course, a few emails/blog comments/interactions with Eric has shown me there is some life in the project - but I think a lot of people get jumpy when it comes to version control software] One thing that might help is splitting bits of darcs into libraries. There have been various things in darcs which are now separate libraries - ByteString and FilePath both have/had parallels in darcs. By making a separate library you get a better documented interface, a cleaner separation of concerns, and people can contribute small patches to self-contained elements, rather than a big application. You also provide additional benefits to the general community :-) Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Analysing Haskell Program
Thomas Davie tom.davie at gmail.com writes: On 1 Aug 2008, at 16:01, Roberto D'Aprile wrote: Hello to everybody I'm using haskell for some research work and now i need to evaluate the performance of some simple haskell programs in particular information on the like, CPU cycles, bus usage, memory access and so on; so i wish to know if there is a way to compile haskell programms so they can be used with simplescalar or if there is another tool which i can use. I've been getting some useful information by compiling with -fvia-C and then using dtrace to look at what's going on. I've been using the basic profiling features built into GHC for profiling. There are more details in the documentation, but basically you can build a binary with profiling support with the options -prof -auto-all to GHC. Then, there are some RTS options at runtime that control the profiling output. I often use +RTS -p -hc -sstderr. These options produce, respectively, a 1) a profile of time spent in and memory used by each function call, 2) a graph of when in time memory was allocated and 3) basic garbage collecting statistics, including how much time was wasted on garbage collection overall. I realize these options don't produce very detailed output, but I find they give a pretty good overview of what's going on. I believe there are also more detailed output options documented in the GHC user manual. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal files on Windows
On Fri, Aug 1, 2008 at 8:39 AM, Duncan Coutts [EMAIL PROTECTED] wrote: On Sun, 2008-07-27 at 21:01 -0500, John Lato wrote: Use Haskell String syntax for paths that contain spaces: include-dirs: C:\\Program Files\\program\\include Hi Duncan, Thanks, this worked (mostly). Although I had to change the line to include-dirs: \C:\\Program Files\\program\\include\ so that the path would be passed properly to cpp through c2hs. Thanks for for filing the ticket John. http://hackage.haskell.org/trac/hackage/ticket/316#comment:1 Turns out Cabal is doing it right and it's c2hs that we need to fix. Shouldn't be too hard. Just need to change the way c2hs invokes cpp in Main.hs: let cmd = unwords [cpp, cppOpts, newHeaderFile, ++ preprocFile] tracePreproc cmd exitCode - liftIO $ system cmd to something like: let args = cppOpts ++ [newHeaderFile] tracePreproc (unwords (cmd : args)) exitCode - liftIO $ do preprocHnd - openFile WriteMode preprocFile process - runProcess cpp args Nothing Nothing Nothing (Just preprocHnd) Nothing waitForProcess process Try that, tell me if it works and we can add the patch to the c2hs repo. I got some compilation errors with this patch. After I changed the top two lines as follows: let args = [cppOpts, newHeaderFile] --cppOpts :: String, not [String] tracePreproc (unwords (cpp:args))--I think you meant cpp instead of cmd here c2hs builds, but I think you can see the problem already. cppOpts needs to be a list of arguments, rather than one string, to use it with runProcess. Now running c2hs yields a cpp error about an invalid argument, specifically -x c -IC:\\Program Files\include. I've added a ticket to trac (#11) for this, and included a patch to fix the problem. Thanks, John ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
