February 2010 - Haskell-Cafe

ICFP 2010: Second call for papers
by Wouter Swierstra 24 Feb '10

24 Feb '10

===================================================================== Second Call for Papers ICFP 2010: International Conference on Functional Programming Baltimore, Maryland, 27 -- 29 September 2010 http://www.icfpconference.org/icfp2010 ===================================================================== Important Dates (at 14:00 UTC) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Submission: 2 April 2010 Author response: 24 -- 25 May 2010 Notification: 7 June 2010 Final papers due: 12 July 2010 Scope ~~~~~ ICFP 2010 seeks original papers on the art and science of functional programming. Submissions are invited on all topics from principles to practice, from foundations to features, from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects or concurrency. Particular topics of interest include * Language Design: type systems; concurrency and distribution; modules; components and composition; metaprogramming; relations to object-oriented or logic programming; interoperability * Implementation: abstract machines; compilation; compile-time and run-time optimization; memory management; multi-threading; exploiting parallel hardware; interfaces to foreign functions, services, components or low-level machine resources * Software-Development Techniques: algorithms and data structures; design patterns; specification; verification; validation; proof assistants; debugging; testing; tracing; profiling * Foundations: formal semantics; lambda calculus; rewriting; type theory; monads; continuations; control; state; effects * Transformation and Analysis: abstract interpretation; partial evaluation; program transformation; program calculation; program proof * Applications and Domain-Specific Languages: symbolic computing; formal-methods tools; artificial intelligence; systems programming; distributed-systems and web programming; hardware design; databases; XML processing; scientific and numerical computing; graphical user interfaces; multimedia programming; scripting; system administration; security; education * Functional Pearls: elegant, instructive, and fun essays on functional programming The conference also solicits Experience Reports, which are short papers that provide evidence that functional programming really works or describe obstacles that have kept it from working in a particular application. Abbreviated instructions for authors ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ By 2 April 2010, 14:00 UTC, submit an abstract of at most 300 words and a full paper of at most 12 pages (6 pages for an Experience Report), including bibliography and figures. The deadline will be strictly enforced and papers exceeding the page limits will be summarily rejected. Authors have the option to attach supplementary material to a submission, on the understanding that reviewers may choose not to look at it. A submission will be evaluated according to its relevance, correctness, significance, originality, and clarity. It should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. The technical content should be accessible to a broad audience. Functional Pearls and Experience Reports are separate categories of papers that need not report original research results and must be marked as such at the time of submission. Detailed guidelines on both categories are on the conference web site. Each submission must adhere to SIGPLAN's republication policy, as explained on the web at http://www.acm.org/sigplan/republicationpolicy.htm. Proceedings will be published by ACM Press. Authors of accepted submissions are expected to transfer the copyright to the ACM. Presentations will be videotaped and released online if the presenter consents by signing an additional permission form at the time of the presentation. Formatting: Submissions must be in PDF format printable in black and white on US Letter sized paper and interpretable by Ghostscript. If this requirement is a hardship, make contact with the program chair at least one week before the deadline. Papers must adhere to the standard ACM conference format: two columns, nine-point font on a ten-point baseline, with columns 20pc (3.33in) wide and 54pc (9in) tall, with a column gutter of 2pc (0.33in). A suitable document template for LATEX is available from SIGPLAN at http://www.acm.org/sigs/sigplan/authorInformation.htm. Submission: Submissions will be accepted electronically at a URL to be named later. Improved versions of a paper may be submitted at any point before the submission deadline using the same web interface. Author response: Authors will have a 48-hour period, starting at 14:00 UTC on 24 May 2010, to read and respond to reviews. Special Journal Issue: There will be a special issue of the Journal of Functional Programming with papers from ICFP 2010. The program committee will invite the authors of select accepted papers to submit a journal version to this issue. Organization ~~~~~~~~~~~~ Conference Chair Paul Hudak, Yale University Program Chair Stephanie Weirich, University of Pennsylvania Program Committee: Umut Acar, Max Planck Institute for Software Systems Zena Ariola, University of Oregon James Cheney, University of Edinburgh Peter Dybjer, Chalmers University of Technology Robert Bruce Findler, Northwestern University Andy Gill, Kansas University Fritz Henglein, University of Copenhagen Michael Hicks, University of Maryland, College Park Patricia Johann, University of Strathclyde Andres Löh, Utrecht University Simon L. Peyton Jones, Microsoft Research Didier Rémy, INRIA Paris-Rocquencourt John Reppy, University of Chicago Manuel Serrano, INRIA Sophia-Antipolis Matthieu Sozeau, Harvard University

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gtk2hs and ghc-6.10.4 on Windows (Vista)
by Alistair Bayley 24 Feb '10

24 Feb '10

On 16 February 2010 17:57, Neil Mitchell <ndmitchell(a)gmail.com> wrote: > Hi Serguey, > > A GHC 6.10.4 version of Gtk2hs: > > http://www.mail-archive.com/gtk2hs-devel@lists.sourceforge.net/msg00340.html > > I used to recommend Gtk2hs over wxHaskell for GUI development as there > was always a version that worked on Windows with the latest GHC > release. I think I might have to switch back to recommending C# for > GUI development... Is there a trick to getting this installed? I have run the installer in a Vista machine, both as user and admin, and the installation is mostly successful, except that the packages are not registered with ghc-6.10.4. Also, the first step of the install complains that "GHC does not appear to be installed correctly, try reinstalling GHC version 6.10.4. Setup found what appears to be a non-working installation of GHC in ..." What test does it apply to determine if GHC is working or not? It can run the gtk-demo, so it's not all bad, but I can't build anything that uses it (like Yi). Alistair

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GHC RTS question
by Artyom Kazak 24 Feb '10

24 Feb '10

Hello everybody! I want to write a little program, that will receive a string as command-line argument and write it in the file. But if this string contains '+RTS', GHC runtime won't pass the rest of the string to my program. What can I do to avoid this?

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Problems linking hsql-mysql
by Maciej Podgurski 24 Feb '10

24 Feb '10

Hi, I have problems linking a simple test program that imports Database.HSQL.MySQL via ghc --make Test.hs. The error only occurs when importing this module of hsql-mysql-1.7.1. I pasted the building output here: http://hpaste.org/fastcgi/hpaste.fcgi/view?id=22911 (actually it was even longer but hpaste only takes 30k). When I do ghc -e main Test.hs or starting it from GHCi, everything works fine and no errors occur. So I guess all needed .lib files are there but GHC can't find them when linking (adding the flag -L"path to mysql/lib/opt" doesn't help). Anyone an idea? Best wishes, Maciej

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Building/installing OS X application bundles for GUIs - cabal-macosx
by Andy Gimblett 24 Feb '10

24 Feb '10

Hi all, Last week I quietly released v0.1.0 of cabal-macosx, providing support for building OSX application bundles (e.g. and in particular for GUIs created using wxHaskell and gtk2hs - hence all the cross-posting): http://hackage.haskell.org/package/cabal-macosx I'm now soliciting input on how to handle the install stage, leading (I hope) to a loudly-announcable release soon. :-) The current package provides a post-build hook which creates an application bundle at dist/build/foo.app (for example). It seems to work well. See the source repository for examples. However, running "runghc Setup install" copies the bare executable at dist/build/foo/foo (rather than the foo.app bundle) to the install location, which is no good. So I need to put in some install infrastructure to copy the .app, not the bare executable, to the right place. That raises the question: what is the right place? It seems to me that the defaults are not the right defaults for this case. --global should probably go to /Applications, and --user should perhaps go to ~/ Applications (though I'm less sure about that). Of course, end-users can explicitly set this on a per-install basis, but it seems that for bundles we'd want to override the default. Thus I'm currently asking: * What do people think about the default installation question? * Can anyone advise me on the right way to handle this (installing the .app, and overriding the default locations) with Cabal? I'm hoping I can just tweak part of the LocalBuildInfo and let the default machinery then handle the work, but at present it's not clear to me how to do that, and rather than spend ages trying to figure it out, perhaps someone who knows can help me out? I'm hoping I'm not going to have to completely override the install machinery - that would feel somewhat self-defeating. Many thanks, -Andy -- Andy Gimblett http://gimbo.org.uk/

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Linux ghci vs Windows ghci
by Donghee Nah 24 Feb '10

24 Feb '10

I'm using Windows 7 32bit Host OS(ghc 6.8.3) and Virtualbox Archlinux Guest OS(ghc 6.8.4) I feel that ghci code executing speed in guest os is 1.5~2x faster than host os The code: let t n = do {if n `mod` 100000 == 0 then print n else return ()} >> t (n+1) t 1 any clue?

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Profiling OpenGL applications
by Sönke Hahn 23 Feb '10

23 Feb '10

On Sunday, Andrew Coppin asked: > Is Thread Scope any use for profiling single-threaded programs? I used threadscope to look at eventlogs from a program that uses OpenGL to render multiple frames per second (compiled without "-threaded"). That means, there is CPU activity regularly (multiple times per second), and this can be observed via threadscope and i found it somewhat useful. There are some problems, though: 1. I can't definitely tell, which time span corresponds to CPU activity for the calculations for one frame. Is it possible to generate threadscope bookmarks from within the profiled program? (Or other events that can be shown in threadscope?) 2. The GPU activity cannot be observed. This is not a problem specific to Haskell, though. Is it even possible (with end user hardware) to get something similar to threadscope, not for CPU, but GPU activity? Any other ideas, that might help gathering information, about what's going on on the CPU(s) and the GPU? Many thanks, Sönke

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Parsing of bytestrings with non-String errors?
by Magnus Therning 23 Feb '10

23 Feb '10

I've looked at polyparse and attoparsec and they seem to have in common that the error always is a String. My current ideas for a project would be a lot easier if I could just return some other type, something that I can pattern match on. Is there a parser combinator library out there that works on bytestrings and allows using a custom error type? Or maybe there's some very basic reason why String is so commonly used? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe

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Alex Lexer: Trying to get rid of "Alex"
by Amit Deshwar 23 Feb '10

23 Feb '10

Hi Haskell-cafe My problem: I'm trying to obtain the current position of the lexer once it reaches the end of the file (line and row number). I'm trying to do this in a function: getEndPosition = do (a,b,c) <- alexGetInput return a Unfortunately, the type of a is 'Alex AlexPosn' instead of just 'AlexPosn' How do I strip the Alex so I'm left with just a AlexPosn object? Thanks, Amit Deshwar University of Calgary

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grapefruit on windows or osX
by gladstein＠gladstein.com 23 Feb '10

23 Feb '10

I'm unable to get grapefruit going on osx or windows because (I think) I can't get the underlying GTK installed. Most recently I can't install gtk2hs over 6.10.4 because the installer tells me my haskell install isn't working and I should reinstall 6.10.1. It invites me to continue anyway and fix the DLL path myself. I continued and it doesn't work; cabal install grapefruit-ui-gtk still fails because it can't find a version of 'gtk'. The gtk demo program does work. Is the situation impossible, or do I just have to somehow tell something about some path? Hope that's all clear, and thanks in advance.

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