January 2011 - Haskell-Cafe

Delivery to haskell-platform@projects.haskell.org
by Magnus Therning 23 Jan '11

23 Jan '11

I'm receiving emails saying that email can't be delivered: Delivery to the following recipient has been delayed: haskell-platform(a)projects.haskell.org Message will be retried for 1 more day(s) Technical details of temporary failure: The recipient server did not accept our requests to connect. Learn more at http://mail.google.com/support/bin/answer.py?answer=7720 [projects.haskell.org (1): Connection timed out] Who should I turn to to get this sorted out? /M -- Magnus Therning OpenPGP: 0xAB4DFBA4 email: magnus(a)therning.org jabber: magnus(a)therning.org twitter: magthe http://therning.org/magnus

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parsing exercise
by Sebastian Fischer 23 Jan '11

23 Jan '11

Hello, I need a function and wonder whether I can copy some existing code so I don't have to write it myself. It should split a string into a list of strings: splitAtTopLevelCommas :: String -> [String] I need something similar to `splitOn ","` from the Text package with the property intercalate "," . splitAtTopLevelCommas = id But it should split the string only on a few commas, not all. You can think of the result list as representations of Haskell values, for example splitAtTopLevelCommas "True,(1,(2,[3,4])),Just ('a',\")\")" should yield ["True", "(1,(2,[3,4]))", "Just ('a',\")\")"] I expect writing this function to be quite tedious (ignore commas in parens, ignore parens in strings, quotation, ...) and would prefer to copy code from some parsing library. Do you have an idea what I could use? Or how to solve it from scratch in a few lines? Sebastian

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Effective function representation.
by Grigory Sarnitskiy 22 Jan '11

22 Jan '11

Hello! I need to deal with functions of type (Double -> Double). I need Fourier transform, integration, + - * / operations, value of a function in a point, probably composition. However it is not very effective to use straightforwardly this type. Since functions in question are rather smooth (if not analytical), the best option would be to use some kind of pointwise representation (e.g. lists, arrays). But in this case the code wouldn't be so easy to understand and implement, compact and so on. Is there some libraries which allow me to work with functions as if their type was (Double -> Double), but indeed it was something faster?

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windows network programming
by Michael Litchard 22 Jan '11

22 Jan '11

I took a quick look on hackage for an interface to windows networking function calls, and didn't find anything that worked. I may have overlooked something. What's the state of windows network programming? Any recommendations for a good package?

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Flushing Cabal's cache
by Aaron Gray 22 Jan '11

22 Jan '11

I am getting the following error :- C:\Languages\Lexer\Haskell>cabal install ranges Resolving dependencies... cabal: Error: some packages failed to install: ranges-0.2.3 failed while unpacking the package. The exception was: user error (TAR checksum error) I am on Windows Vista, is it possible to clean or delete Cabal's cache ? Many thanks in advance, Aaron

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6th Ghent Functional Programming Group Meeting: 17/02/2011
by Jasper Van der Jeugt 22 Jan '11

22 Jan '11

(apologies if you receive multiple copies) Dear all, We would like to announce that the sixth Ghent Functional Programming Group Meeting will take place on Thursday, February 17, in the Technicum Building (Sint-Pietersnieuwstraat 41, 9000 Gent) of Ghent University at 19h. We will use the "Gobelijn" room this time. To bring some variation into the concept, we will host a problem solving meeting instead of talks. Bring your favorite functional programming language, a laptop with a wireless card (if possible), and the willingness to work together in small groups with other attendees on some interesting problems. We would like to note that is not a contest as such, we want to focus on elegance and working together instead of finding a quick and dirty solution. A beamer will be available if someone wants to give a quick explanation on his/her solution. For more information you can follow us at twitter (@ghentfpg) or sign up for our google group (http://groups.google.com/group/ghent-fpg) Hope to see you all then, The GhentFPG organizing committee, Andy Georges Jeroen Janssen Jasper Van der Jeugt

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Re: [Haskell-cafe] Splittable random numbers
by Ryan Newton 22 Jan '11

22 Jan '11

I'm not too familiar with all the Haskell API's for RNGs. This is the first time I've looked at CryptoRandomGen, but I can see the benefit of having a bytestring interface rather than the System.Random Int based one. Is there a reason that the AES implementation in the "AES" or "crypto" packages can't be ripped out and repackage in the way you would like? Cheers, -Ryan On Fri, Jan 21, 2011 at 6:11 PM, Thomas DuBuisson < thomas.dubuisson(a)gmail.com> wrote: > Ryan, > If you make an AES based RNG then consider making an instance for > CryptoRandomGen (see DRBG [1] for example instances). Such an > instance means you can use "splitGen" [2], which can split generators > in the manner described in this thread. If you make the RNG match > NIST SP 800-90 then feel free to send it to me for inclusion in the > DRBG package, I've been meaning to make the block cipher based DRBG > for a while now. > > Finally, any implementation of AES (using NI or not) could probably go > in its own package or a cipher-specific package like CryptoCipher[3]. > Its a shame we don't have an AES implementation on Hackage that 1) > exposes the fundamental block interface instead of some higher-level > wrapping and 2) isn't tied to a large library. > > Cheers, > Thomas > > [1] http://hackage.haskell.org/package/DRBG > and > > http://hackage.haskell.org/packages/archive/DRBG/0.1.2/doc/html/src/Crypto-… > [2] > http://hackage.haskell.org/packages/archive/crypto-api/0.3.1/doc/html/Crypt… > [3] http://hackage.haskell.org/package/cryptocipher > > > On Fri, Jan 21, 2011 at 2:19 PM, Ryan Newton <rrnewton(a)gmail.com> wrote: > > Hi cafe, > > > > I want to add the ability to use AES-NI instructions on Intel > architectures > > to GHC. Mainly I'd like to do splittable random number generators based > on > > AES as was suggested at the outset of this email. (I met Burton Smith > last > > week and this topic came up.) > > > > I was just reading the below thread about the plugin architecture which > got > > me thinking about what the right way to add AES-NI is. (Disregarding for > a > > moment portability and the issue of where to test cpuid...) > > > > > http://www.haskell.org/pipermail/glasgow-haskell-users/2011-January/019874.… > > > > The FFI is always an option. But after reading the first N pages I could > > come across from google I'm still not totally clear on whether "unsafe" > > foreign calls can happen simultaneously from separate Haskell threads > (and > > with sufficiently low overhead for this purpose). > > > > I also ran across the phrase "compiler primitive" somewhere wrt GHC: > > > http://hackage.haskell.org/trac/ghc/wiki/AddingNewPrimitiveOperations > > > > Is that the right way to go? Or would the compiler plugin mechanism > > possibly allowing doing this without modifying mainline GHC? > > > > Thanks, > > -Ryan > > > > On Fri, Nov 12, 2010 at 6:26 PM, wren ng thornton <wren(a)freegeek.org> > wrote: > >> > >> On 11/12/10 5:33 AM, Richard Senington wrote: > >>> > >>> It does not give the results you would want. This may have something to > >>> do with picking "good" parameters for the mkLehmerTree function. > >>> For example, using a random setup, I just got these results > >>> result expected range > >>> 16.814 expected = 16.0 (1,31) > >>> 16.191 expected = 16.5 (1,32) > >>> 16.576 expected = 17.0 (1,33) > >>> 17.081 expected = 17.5 (1,34) > >>> 17.543 expected = 18.0 (1,35) > >> > >> Have you run any significance tests? I wouldn't be surprised to see > +/-0.5 > >> as within the bounds of expected randomness. I'm more worried about it > >> seeming to be consistently on the -0.5 end of things, than I am about it > not > >> matching expectation (how many samples did you take again?). For small > >> ranges like this, a consistent -0.5 (or +0.5) tends to indicate > off-by-one > >> errors in the generator. > >> > >> -- > >> Live well, > >> ~wren > >> _______________________________________________ > >> Haskell-Cafe mailing list > >> Haskell-Cafe(a)haskell.org > >> http://www.haskell.org/mailman/listinfo/haskell-cafe > > > > > > _______________________________________________ > > Glasgow-haskell-users mailing list > > Glasgow-haskell-users(a)haskell.org > > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > > > > >

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Problems installing the haskell platform
by Henry Laxen 21 Jan '11

21 Jan '11

Dear Group, Greetings. I've been using haskell for about a year now, though I will readily admit I still don't really know what I am doing when I get error messages. Today I decided to reset my haskell environment from scratch, avoiding the debian packages and going straight to the source. 1. Install ghc from http://www.haskell.org/ghc/download_ghc_6_12_3 Success!! ghc --version The Glorious Glasgow Haskell Compilation System, version 6.12.3 cabal update Downloading the latest package list from hackage.haskell.org 2. Next I downloaded the haskell platform and ran cabal install Problems!! cabal: Error: some packages failed to install: haskell-platform-2010.2.0.0 depends on stm-2.1.2.1 which failed to install. stm-2.1.2.1 failed during the building phase. The exception was: ExitFailure 1 3. So I tried installing stm manually, which for some unknown reason worked: runghc Setup.hs install Installing library in /usr/local/lib/stm-2.1.2.1/ghc-6.12.3 Registering stm-2.1.2.1... 4. back to the haskell-platform directory and try again: cabal install Resolving dependencies... Configuring haskell-platform-2010.2.0.0... setup: happy version ==1.18.5 is required but the version found at /usr/local/bin/happy is version 1.18.6 cabal: Error: some packages failed to install: haskell-platform-2010.2.0.0 failed during the configure step. The exception was: ExitFailure 1 5. Crap. Okay, maybe it will work with version 1.18.6 after all, so I edit the .cabal and change happy ==1.18.5 to happy >=1.18.5 -- Depending on programs does not work, they are not registered -- We list them to help distro packaging. build-tools: cabal-install ==0.8.2, alex ==2.3.3, happy >=1.18.5 -- haddock ==2.7.2 -- valid, but needs ghc-paths 6. Try again cabal install Resolving dependencies... Configuring haskell-platform-2010.2.0.0... Preprocessing library haskell-platform-2010.2.0.0... Building haskell-platform-2010.2.0.0... Registering haskell-platform-2010.2.0.0... Installing library in /usr/local/lib/haskell-platform-2010.2.0.0/ ghc-6.12.3 Registering haskell-platform-2010.2.0.0... 7. Success!! Now even though I'm not sure what I am doing, it looks like it may have worked. I'm worried, though, about the first time user who tries to go through this process. They will probably stop at the first error, when the haskell-platform fails to install. I know some of you will say use the debian packages. Well I did that, but when I tried to install snap, which is not included in the debian packages, I wound up with conflicting dependencies, and could not find a way out. I hope this dialog is helpful to whomever is in charge of the haskell platform, a wonderful resource by the way. Best wishes, Henry Laxen

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CfP: The 9th International Conference on SOFTWARE ENGINEERING AND FORMAL METHODS (SEFM'11)
by Juan Manuel Crespo 21 Jan '11

21 Jan '11

CALL FOR PAPERS - SEFM 2011 The 9th International Conference on SOFTWARE ENGINEERING AND FORMAL METHODS (SEFM) 14-18 November 2011 Montevideo, Uruguay URL: http://www.fing.edu.uy/inco/eventos/SEFM2011 ++++++++++++++++++++++++++++++++++++++++++ IMPORTANT DATES * Title and abstract submission deadline: 23 April 2011 * Paper submission deadline: 30 April 2011 * Acceptance/rejection notification: 15 June 2011 * Camera-ready version due: 15 July 2011 +++++++++++++++++++++++++++++++++++++++++++++++++++ BACKGROUND AND OBJECTIVES The aim of the conference is to bring together practitioners and researchers from academia, industry and government to advance the state of the art in formal methods, to facilitate their uptake in the software industry and to encourage their integration with practical engineering methods. Papers that combine formal methods and software engineering are especially welcome. Authors are invited to submit original research or tool papers on any relevant topic. These can either be normal or short papers. Short papers can discuss new ideas which are at an early stage of development and which have not yet been thoroughly evaluated. TOPICS Topics of interest include, but are not limited to: * formal requirement analysis, specification and design * programming languages, program analysis and type theory * formal methods for service-oriented and cloud computing * formal aspects of security and mobility * model checking, theorem proving and decision procedures * formal methods for real-time, hybrid and embedded systems * formal methods for safety-critical, fault-tolerant and secure systems * software architecture and coordination languages * component, object and multi-agent systems * formal aspects of software evolution and maintenance * formal methods for testing, re-engineering and reuse * light-weight and scalable formal methods * tool integration * applications of formal methods, industrial case studies and technology transfer KEYNOTE SPEAKERS * Daniel Le Métayer - INRIA, France * More to be announced... SPECIAL TRACK The conference programme will include a special track on "Modelling for Sustainable Development". A separate Call for Papers is available for the special track. All queries on submissions to the special track should be sent to: sefm2011-msd(a)iist.unu.edu. LOCATION The conference will be held at the NH Columbia Hotel located close to the financial center of Montevideo and enjoying excellent views of the Plata river (Río de la Plata) - http://www.nh-hotels.com/nh/en/hotels/uruguay/montevideo/nh-columbia.html. SUBMISSION AND PUBLICATION Submissions to the conference must not have been published or be concurrently considered for publication elsewhere. All submissions will be peer-reviewed and judged on the basis of originality, contribution to the field, technical and presentation quality, and relevance to the conference. All papers must be written in English. Research and tool papers must not exceed 16 pages in the LNCS format while short papers must not exceed 8 pages in the LNCS format (see http://www.springer.de/comp/lncs/authors.html for details). All queries on the submissions should be sent to: sefm2011(a)fing.edu.uy. Papers must be submitted electronically via the Easychair System: http://www.easychair.org/conferences/?conf=sefm11 The proceedings will be published in the Springer Lecture Notes in Computer Science series (LNCS). After the conference, authors of selected papers will be invited to submit an extended version of their work to be considered for publication in a special issue of the SoSyM journal (Software and Systems Modeling, Springer), following the standard reviewing process of the journal. COMMITTEES Conference Chair * Alberto Pardo, Universidad de la República, Uruguay Program Co-chairs * Gilles Barthe, IMDEA Software, Spain * Gerardo Schneider, Chalmers | Univ. of Gothenburg, Sweden Program Committee * Bernhard K. Aichering (Graz University of Technology, Austria) * Luis Barbosa (University of Minho, Portugal) * Gilles Barthe (IMDEA Software, Spain) * Thomas Anung Basuki (UNU-IIST, China) * Alexandre Bergel (University of Chile, Chile) * Gustavo Betarte (Universidad de la República, Uruguay) * Ana Cavalcanti (University of York, UK) * Pedro R. D'Argenio (Univ. Nacional de Córdoba, Argentina) * Van Hung Dang (UNU-IIST, China) * George Eleftherakis (SEERC, Greece) * José Luiz Fiadeiro (University of Leicester, UK) * Martin Fränzle (Oldenburg University, Germany) * Stefania Gnesi (ISTI-CNR, Italy) * Rob Hierons (Brunel University, UK) * Paola Inverardi (University of L'Aquila, UK) * Jean-Marie Jacquet (University of Namur, Belgium) * Tomasz Janowski (UNU-IIST, China) * Jean-Marc Jezequel (IRISA, France) * Joseph Kiniry (IT University of Copenhagen, Denmark) * Paddy Krishnan (Bond University, Australia) * Martin Leucker (TU Munich, Germany) * Xuandong Li (Nanjing University, China) * Peter Lindsay (The University of Queensland, Australia) * Antónia Lopes (University of Lisbon, Portugal) * Nenad Medvidovic (University of Southern California, USA) * Mercedes Merayo (Universidad Complutense de Madrid, Spain) * Stephan Merz (INRIA Nancy, France) * Madhavan Mukund (Chennai Mathematical Institute, India) * Cesar Muñoz (NASA, USA) * Martín Musicante (UFRN, Brazil) * Mizuhito Ogawa (JAIST, Japan) * Olaf Owe (University of Oslo, Norway) * Gordon Pace (University of Malta, Malta) * Ernesto Pimentel (University of Málaga, Spain) * Sanjiva Prasad (Indian Institute of Technology Delhi, India) * Anders Ravn (Aalborg University, Denmark) * Leila Ribeiro (UFRGS, Brazil) * Augusto Sampaio (UFPE, Brazil) * Gerardo Schneider (Chalmers | Univ. of Gothenburg, Sweden) * Sebastian Uchitel (Imperial College London, UK) * Willem Visser (University of Stellenbosch, South Africa) * Sergio Yovine (VERIMAG, France) Organising Committee * Carlos Luna, Universidad de la República, Uruguay * Alberto Pardo, Universidad de la República, Uruguay * Luis Sierra, Universidad de la República, Uruguay Steering Committee * Manfred Broy, TU Munich, Germany * Antonio Cerone, UNU-IIST, Macao SAR, China * Mike Hinchey, Lero-The Irish Software Engineering Research Centre, Ireland * Mathai Joseph, TRDDC, Pune, India * Zhiming Liu, UNU-IIST, Macao SAR, China * Andrea Maggiolo-Schettini, Pisa University, Italy ===================================================

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Looking for criticism and comments on web-mongrel2.
by Clint Moore 21 Jan '11

21 Jan '11

After sufficient hand-wringing I finally uploaded web-mongrel2 up to hackage and I'm interested in criticism of my approach. The module itself is terribly simple as it's meant to provide a lightweight layer between an application or framework and Mongrel2, but if nothing else, it's a start. Anyway, the hackage page is at http://hackage.haskell.org/package/web-mongrel2-0.0.2.2 with a link to the github repo.

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