February 2010 - Haskell

ANNOUNCE: ioctl 0.0.1
by Maciej Piechotka 13 Sep '15

13 Sep '15

A package for type-safe I/O control. Currently only ioctl is supported. Currently simply a extract from my tuntap fork TODO: - Return the integer as well as structure (will break the API) - Port for Windows Network.Socket.IOCtl (as soon as I manage to setup some sane environment on this platform) - Wrapping around DeviceIoControl Example (in hsc): data NotRead = NotRead instance NotRead Int where ioctlReq _ = #const FIONREAD notRead s = ioctlsocket' s NotRead Regards

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Announcing Djinn, version 2004-12-11, a coding wizard
by Lennart Augustsson 07 Apr '11

07 Apr '11

Howdy, y'all! I've written a small program that takes a (Haskell) type and gives you back a function of that type if one exists. It's kind of fun, so I thought I'd share it. It's probably best explained with a sample session. calvin% djinn Welcome to Djinn version 2005-12-11. Type :h to get help. # Djinn is interactive if not given any arguments. # Let's see if it can find the identity function. Djinn> f ? a->a f :: a -> a f x1 = x1 # Yes, that was easy. Let's try some tuple munging. Djinn> sel ? ((a,b),(c,d)) -> (b,c) sel :: ((a, b), (c, d)) -> (b, c) sel ((_, v5), (v6, _)) = (v5, v6) # We can ask for the impossible, but then we get what we # deserve. Djinn> cast ? a->b -- cast cannot be realized. # OK, let's be bold and try some functions that are tricky to write: # return, bind, and callCC in the continuation monad Djinn> type C a = (a -> r) -> r Djinn> returnC ? a -> C a returnC :: a -> C a returnC x1 x2 = x2 x1 Djinn> bindC ? C a -> (a -> C b) -> C b bindC :: C a -> (a -> C b) -> C b bindC x1 x2 x3 = x1 (\ c15 -> x2 c15 (\ c17 -> x3 c17)) Djinn> callCC ? ((a -> C b) -> C a) -> C a callCC :: ((a -> C b) -> C a) -> C a callCC x1 x2 = x1 (\ c15 _ -> x2 c15) (\ c11 -> x2 c11) # Well, poor Djinn has a sweaty brow after deducing the code # for callCC so we had better quit. Djinn> :q Bye. To play with Djinn do a darcs get http://darcs.augustsson.net/Darcs/Djinn or get http://darcs.augustsson.net/Darcs/Djinn/Djinn.tar.gz Then just type make. (You need a Haskell 98 implementation and some libraries.) And then start djinn. For the curious, Djinn uses a decision procedure for intuitionistic propositional calculus due to Roy Dyckhoff. It's a variation of Gentzen's LJ system. This means that (in theory) Djinn will always find a function if one exists, and if one doesn't exist Djinn will terminate telling you so. This is the very first version, so expect bugs. :) Share and enjoy. -- Lennart

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ANN: Try Haskell! An interactive tutorial in your browser
by DekuDekuplex＠Yahoo.com 01 Mar '10

01 Mar '10

According to the top page of HaskellWiki (see http://www.haskell.org/) (under "February 2010" under "1 Headlines"), there is an alpha version of a new interactive, online Haskell interpreter entitled "Try Haskell!" at http://tryhaskell.org/. The top panel of the page features an interactive interpreter, while the bottom panel features a text tutorial. The user types in commands in the top panel according to the text tutorial, and the interpreter responds with output. There is also a "Reset" button in the upper right corner of the tool which resets the state of both panels to the default state. I just tried it out, and it appears to have been completed up to Lesson 3. So far, it apparently teaches up to lists. It was fun to try out. This tutorial somehow reminded me of an interactive Scheme tutorial, "Lists And Lists," copyrighted in 1996 by Andrew Plotkin, at http://parchment.googlecode.com/svn/trunk/parchment.html?story=http://parch…. That tutorial was arranged in the style of an adventure game, while this tutorial is more similar to a very similar Ruby tutorial, "try ruby! (in your browser)" at http://TryRuby.org/. It could be fun if somebody could come up with a Haskell version of the above-mentioned"Lists And Lists," which also includes a text-based Scheme reference on the virtual computer within the adventure game. -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

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MSFP: Call for Papers
by Venanzio Capretta 28 Feb '10

28 Feb '10

Third Workshop on MATHEMATICALLY STRUCTURED FUNCTIONAL PROGRAMMING 25 September 2010, Baltimore, USA A satellite workshop of ICFP 2010 PRESENTATION The workshop on Mathematically Structured Functional Programming is devoted to the derivation of functionality from structure. It is a celebration of the direct impact of Theoretical Computer Science on programs as we write them today. Modern programming languages, and in particular functional languages, support the direct expression of mathematical structures, equipping programmers with tools of remarkable power and abstraction. Monadic programming in Haskell is the paradigmatic example, but there are many more mathematical insights manifest in programs and in programming language design: Freyd-categories in reactive programming, symbolic differentiation yielding context structures, and comonadic presentations of dataflow, to name but three. This workshop is a forum for researchers who seek to reflect mathematical phenomena in data and control. The first MSFP workshop was held in Kuressaare, Estonia, in July 2006. Selected papers were published as a special issue of the Journal of Functional Programming (volume 19, issue 3-4). The second MSFP workshop was held in Reykjavik, Iceland as part of ICALP 2008. SUBMISSIONS Papers must report previously unpublished work and not be submitted concurrently to another conference with refereed proceedings. Programme Committee members, barring the co-chairs, may (and indeed are encouraged to) contribute. Accepted papers must be presented at the workshop by one of the authors. There is no specific page limit, but authors should strive for brevity. We are using the EasyChair software to manage submissions. To submit a paper, please log in at: http://www.easychair.org/conferences/?conf=msfp2010 The workshop proceedings will be published by ACM. TIMELINE: Submission of abstracts: 9 April Submission of papers: 16 April Notification: 28 May Final versions due: 25 June Workshop: 25 September For more information about the workshop, go to: http://cs.ioc.ee/msfp/msfp2010/ Programme Committee * Andreas Abel, LMU Munich, Germany * Ana Bove, Chalmers University of Technology, Gothenburg, Sweden * Andrej Bauer, University of Ljubljana, Slovenia * Venanzio Capretta (co-chair), University of Nottingham, UK * James Chapman (co-chair), Institute of Cybernetics, Tallinn, Estonia * Adam Chlipala, Harvard University, Cambridge, MA, USA * Catarina Coquand, Chalmers University of Technology, Gothenburg, Sweden * Karl Crary, Carnegie Mellon University, Pittsburgh, USA * Manuel Alcino Cunha, Universidade do Minho, Braga, Portugal * Andy Gill, University of Kansas, USA * Mauro Jaskelioff, Universidad Nacional de Rosario, Argentina * Oleg Kiselyov, FNMOC, Monterey, California, USA * Lionel Elie Mamane, Radboud University Nijmegen, The Netherlands * Conor McBride, University of Strathclyde, Glasgow, UK * Greg Morrisett, Harvard University, Cambridge, MA, USA * Russell O'Connor, McMaster University, Hamilton, Ontario, Canada * Benoit Razet, TIFR (Tata Institute of Fundamental research), India * Carsten Schrmann, IT University of Copenhagen, Denmark * Wouter Swierstra, Chalmers University of Technology, Gothenburg, Sweden * Tarmo Uustalu, Institute of Cybernetics, Tallinn, Estonia * Varmo Vene, University of Tartu, Estonia

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ANNOUNCE: darcs 2.4
by Reinier Lamers 27 Feb '10

27 Feb '10

Hi all, The darcs team is proud to announce the immediate availability of darcs 2.4. darcs 2.4 contains many improvements and bugfixes compared to darcs 2.3.1. Highlights are the faster operation of record, revert and related commands, and the experimental interactive hunk editing. This makes darcs 2.4 the latest and greatest in easy version control. The easiest way to install darcs is using the Haskell Platform [1]. If you have installed the Haskell Platform or cabal-install, you can install this beta release by doing: $ cabal update $ cabal install --reinstall darcs Alternatively, you can download the tarball from http://darcs.net/releases/darcs-2.4.tar.gz , and build it by hand as explained in the README file. Interactive hunk editing ------------------------ To try out interactive hunk editing, press 'e' when you are prompted with a hunk patch by 'darcs record'. You will then be shown an editor screen in which you can edit the state you want to record between the last two ruler lines. You can find more information about the hunk editing feature on http://wiki.darcs.net/HunkEditor . What's New ---------- A list of important changes since 2.3.1 is as follows: * Use fast index-based diffing everywhere (Petr) * Interactive patch splitting (Ganesh) * An 'optimize --upgrade' option to convert to hashed format in-place (Eric) * Hunk matching (Kamil Dworakowski, tat.wright) * Progress reporting is no longer deceptive (Roman) * A 'remove --recursive' option to remove a directory tree from revision control (Roman) * 'show files' accepts arguments to show a subset of tracked files (Luca) * A '--remote-darcs' flag for pushing to a host where darcs isn't called darcs * Many miscellaneous Windows improvements (Salvatore, Petr and others) * 'darcs send' now mentions the repository name in the email body (Joachim) * Handle files with boring names in the repository correctly (Petr) * Fix parsing of .authorspellings file (Tomáš) * Various sane new command-line option names (Florent) * Remove the '--checkpoint' option (Petr) * Use external libraries for all UTF-8 handling (Eric, Reinier) * Use the Haskell zlib package exclusively for compression (Petr) A list of issues resolved since 2.3.1: * 183: do not sort changes --summary output * 223: add --remote-darcs flag to specify name of remote darcs executable * 291: provide (basic) interactive patch splitting * 540: darcs remove --recursive * 835: 'show files' with arguments * 1122: get --complete should not offer to create a lazy repository * 1216: list Match section in ToC * 1224: refuse to convert a repo that's already in darcs-2 format * 1300: logfile deleted on unsucessful record * 1308: push should warn about unpulled patches before patch-selection * 1336: sane error message on --last "" (empty string to numbers parser) * 1362: mention repo name in mail send body * 1377: getProgname for local darcs instances * 1392: use parsec to parse .authorspelling * 1424: darcs get wrongly reports "using lazy repository" if you ctrl-c old-fashioned get * 1447: different online help for send/apply --cc * 1488: fix crash in whatsnew when invoked in non-tracked directory * 1548: show contents requires at least one argument * 1554: allow opt-out of -threaded (fix ARM builds) * 1563: official thank-you page * 1578: don't put newlines in the Haskeline prompts * 1583: on darcs get, suggest upgrading source repo to hashed * 1584: provide optimize --upgrade command * 1588: add --skip-conflicts option * 1594: define PREPROCHTML in makefile * 1620: make amend leave a log file when it should * 1636: hunk matching * 1643: optimize --upgrade should do optimize * 1652: suggest cabal update before cabal install * 1659: make restrictBoring take recorded state into account * 1677: create correct hashes for empty directories in index * 1681: preserve log on amend failure * 1709: fix short version of progress reporting * 1712: correctly report number of patches to pull * 1720: fix cabal haddock problem * 1731: fix performance regression in check and repair * 1741: fix --list-options when option has multiple names * 1749: refuse to remove non-empty directories Performance ----------- darcs in its current form does not perform very well on huge repositories. In order to systematically address this issue, and to catch performance regressions, we have started a darcs benchmarking project. You can find benchmarks of darcs performance in many different situations on http://wiki.darcs.net/Benchmarks . On http://wiki.darcs.net/Benchmarks/Quasar you will find graphs of the benchmark results on a Windows Vista machine. On that page, you will also find instructions on how to run your own darcs benchmarks. Reporting bugs -------------- If you have an issue with darcs 2.4, you can report it via the web on http://bugs.darcs.net/ . You can also report bugs by email to bugs(a)darcs.net. Kind Regards, the darcs release manager, Reinier Lamers [1]: You can download the Haskell platform from http://hackage.haskell.org/platform/

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MSFP: Call for Papers
by Venanzio Capretta 26 Feb '10

26 Feb '10

Third Workshop on MATHEMATICALLY STRUCTURED FUNCTIONAL PROGRAMMING 25 September 2010, Baltimore, USA A satellite workshop of ICFP 2010 PRESENTATION The workshop on Mathematically Structured Functional Programming is devoted to the derivation of functionality from structure. It is a celebration of the direct impact of Theoretical Computer Science on programs as we write them today. Modern programming languages, and in particular functional languages, support the direct expression of mathematical structures, equipping programmers with tools of remarkable power and abstraction. Monadic programming in Haskell is the paradigmatic example, but there are many more mathematical insights manifest in programs and in programming language design: Freyd-categories in reactive programming, symbolic differentiation yielding context structures, and comonadic presentations of dataflow, to name but three. This workshop is a forum for researchers who seek to reflect mathematical phenomena in data and control. The first MSFP workshop was held in Kuressaare, Estonia, in July 2006. Selected papers were published as a special issue of the Journal of Functional Programming (volume 19, issue 3-4). The second MSFP workshop was held in Reykjavik, Iceland as part of ICALP 2008. SUBMISSIONS Papers must report previously unpublished work and not be submitted concurrently to another conference with refereed proceedings. Programme Committee members, barring the co-chairs, may (and indeed are encouraged to) contribute. Accepted papers must be presented at the workshop by one of the authors. There is no specific page limit, but authors should strive for brevity. We are using the EasyChair software to manage submissions. To submit a paper, please log in at: http://www.easychair.org/conferences/?conf=msfp2010 The workshop proceedings will be published by ACM. TIMELINE: Submission of abstracts: 9 April Submission of papers: 16 April Notification: 28 May Final versions due: 25 June Workshop: 25 September For more information about the workshop, go to: http://cs.ioc.ee/msfp/msfp2010/ Programme Committee * Andreas Abel, LMU Munich, Germany * Ana Bove, Chalmers University of Technology, Gothenburg, Sweden * Andrej Bauer, University of Ljubljana, Slovenia * Venanzio Capretta (co-chair), University of Nottingham, UK * James Chapman (co-chair), Institute of Cybernetics, Tallinn, Estonia * Adam Chlipala, Harvard University, Cambridge, MA, USA * Catarina Coquand, Chalmers University of Technology, Gothenburg, Sweden * Karl Crary, Carnegie Mellon University, Pittsburgh, USA * Manuel Alcino Cunha, Universidade do Minho, Braga, Portugal * Andy Gill, University of Kansas, USA * Mauro Jaskelioff, Universidad Nacional de Rosario, Argentina * Oleg Kiselyov, FNMOC, Monterey, California, USA * Lionel Elie Mamane, Radboud University Nijmegen, The Netherlands * Conor McBride, University of Strathclyde, Glasgow, UK * Greg Morrisett, Harvard University, Cambridge, MA, USA * Russell O'Connor, McMaster University, Hamilton, Ontario, Canada * Benoit Razet, TIFR (Tata Institute of Fundamental research), India * Carsten Schrmann, IT University of Copenhagen, Denmark * Wouter Swierstra, Chalmers University of Technology, Gothenburg, Sweden * Tarmo Uustalu, Institute of Cybernetics, Tallinn, Estonia * Varmo Vene, University of Tartu, Estonia

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Interested in the Dutch HUG Day (24 April 2010)?
by Sean Leather 25 Feb '10

25 Feb '10

In honor of the first anniversary of the Dutch Haskell Users Group (formed at Hac5 in Utrecht), we are planning a mini symposium to bring together Haskell and functional programming enthusiasts in the Netherlands and surrounding area. *The Dutch HUG Day will be held on Saturday, 24 April.* Please mark that date in your calendar. The remaining details are being worked out. In order to help us with this process, we have created a short survey. If you are even remotely considering attending, please take a moment to fill out a form with your name and the activities that interest you. * http://spreadsheets.google.com/viewform?formkey=dGVuVTdnZEl0ZDE3MEVweUtRdml… Note that this does not commit you to anything. We will only use this information to help plan the event (e.g. determine the number of seats at the location and the types of activities). For more information about the Dutch HUG, visit the wiki page and sign up for the mailing list. * http://www.haskell.org/haskellwiki/Dutch_HUG * http://groups.google.com/group/dutch-hug Thanks for your time! Sincerely, The Dutch HUG Day planning team

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ANN: concurrent-extra-0.2
by Roel van Dijk 24 Feb '10

24 Feb '10

Hello, We would like to announce an update of concurrent-extra [1]. Bug fixes: - A bug in RLock.acquire (thanks to Felipe Lessa). New features: - Broadcast: Wake multiple threads by broadcasting a value. This is a generalisation of Event. - Thread: Threads extended with the ability to wait for their termination. - delay: Arbitrarily long thread delays. - timeout: Wait arbitrarily long for an IO computation to finish. The lightweight thread wrapper was inspired by the threadmanager package [2]. The main advantage of our implementation is that we don't maintain an internal mapping from ThreadId to ThreadStatus. Instead we rely on the forked thread to broadcast its status to interested listeners. This should result in better performance (no lookup required). Every exported symbol is now documented. Regards, Roel & Bas van Dijk [1] http://hackage.haskell.org/package/concurrent-extra-0.2 [2] http://hackage.haskell.org/package/threadmanager-0.1.3

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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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Haskell Weekly News: Issue 150 - February 22, 2010
by jfredett＠gmail.com 24 Feb '10

24 Feb '10

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20100222 Issue 150 - February 22, 2010 --------------------------------------------------------------------------- Welcome to issue 150 of HWN, a newsletter covering developments in the [1]Haskell community. From the very pits of Harddrive failure I return... The Haskell Weekly News Reborn! Last week, on friday, my HWN machine suffered what can only be appropriately named a unbelievably poorly timed hard drive failure, hence the lack of an HWN. I trumphently return this week with a megaedition. Tons and tons of awesome stuff happened in the last two weeks. So I won't make you wait any longer, haskellers, your Haskell Weekly News! Announcements vty-ui 0.3. Jonathan Daugherty [2]announced a new version of vty-ui, featuring a richer rendering engine, generalized text transformations, and a more functional style. darcs 2.4 release candidate 2. Reinier Lamers [3]announced a new release candidate for darcs 2.4. iteratee-parsec 0.0.1. Maciej Piechotka [4]announced the release of iteratee-parsec, a library whih provides support for parsec parsers in an Iteratee monad. concurrent-extra-0.1. Roel van Dijk [5]announced the release of concurrent-extra, which provides a few new synchronization primitives. wyvern, a Dragon Go Server 'client'. wagnerdm [6]announced wyvern, a Dragon Go Server 'client', which plays moves for you on the [7]Dragon Go Server. atom-1.0.0. Tom Hawkins [8]announced a new major release of the atom library. Call for Copy: Monad.Reader Issue 16. Brent Yorgey [9]announced the call for copy for Monad.Reader issue 16. hmatrix 0.8.3. Alberto Ruiz [10]announced a new version of hmatrix. First Atlanta Function Programming Users Group Meeting. David Vollbracht [11]announced the first Atlanta FP Group meetup. TFP 2010 - Call for Papers and Participation. Simon Marlow [12]announced a call for papers and particpation in TFP 2010, the 11th Symposium on Trends in Functional Programming. CMCS 2010: Call for Short Submissions & Call for Participation. Alexandra Silva [13]announced a call for short submissions and participation in the 10th International Workshop on Coalgebraic Methods in Computer Science. WGP 2010 Call for Papers. Bruno Oliveira [14]announced a call for papers for Workshop on Generic Programming. ICE 2010: First call for papers. Alexandra Silva [15]announced the first call for papers for ICE2010, the 3rd Interation and Concurrency Experience workshop. Call for Papers: Haskell Symposium 2010. Jeremy.Gibbons [16]announced a call for papers for the 2010 Haskell Symposium. Dungeons of Wor - a largish FRP example and a fun game, all in one! Patai Gergely [17]announced Dungeons of Wor, a Game written in Haskell using the Elerea library and Functional Reactive Techniques. Discussion The Related monad and constant values in type classes. Jonas Almstroem Duregard [18]talked about a common pattern which occurs when associating data with a type (as opposed to a value). Heterogeneous Data Structures - Nested Pairs and functional references. Guenther Schmidt [19]asked about different ways to implement heterogeonous datastructures. Blog noise [20]Haskell news from the [21]blogosphere. Blog posts from people new to the Haskell community are marked with >>>, be sure to welcome them! * Michael Snoyman: [22]Four HTTP Request Body Interfaces (repost). * Brent Yorgey: [23]Math.Combinatorics.Multiset. * Darcs: [24]darcs weekly news #55. * Galois, Inc: [25]Tech Talk: Modern Benchmarking in Haskell. * Ketil Malde: [26]Tools for pyrosequencing analysis. * Arch Haskell News: [27]Arch Haskell News: February 2010. * Don Stewart (dons): [28]Migrating from uvector to vector. * GHC / OpenSPARC Project: [29]Memory Barriers and GHC 6.12.1. * Darcs: [30]darcs weekly news #54. * Gergely Patai: [31]Behind the dungeons. * David Amos: [32]How to find a strong generating set. Quotes of the Week * fasta: And by cool, I mean 'that is not supposed to happen'. * uncyclopedia: Calculations which are undefined are denoted by the _|_ symbol, pronounced Bottom, which the documentation explains as the compiler giving you the finger. * Draconx|Laptop: mathematics is the art of finding different ways to write "therefore". * medfly: Cale, #haskell wants to know all your personal preferences so we can all copy you * Cale: Gentoo is a massive waste of electricity. * hobophobe: So, I can only conclude that Haskell is a memetic virus, and monads are the eggs it lays out in innocent programming forums to entice others to become infected. * benmachine: unsafeCoerce is just a generalisation of id * jmcarthur: what good is a state monad if your state is basically 'i have no idea what the hell my state is'? About the Haskell Weekly News New editions are posted to [33]the Haskell mailing list as well as to [34]the Haskell Sequence and [35]Planet Haskell. [36]RSS is also available, and headlines appear on [37]haskell.org. To help create new editions of this newsletter, please see the information on [38]how to contribute. Send stories to jfredett . at . gmail . dot . com. The darcs repository is available at darcs get [39]http://patch-tag.com/r/jfredett/HWN2/pullrepo HWN2 . References 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70589 3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70563 4. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70533 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70485 6. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70344 7. http://www.dragongoserver.net/ 8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70328 9. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70314 10. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70290 11. http://article.gmane.org/gmane.comp.lang.haskell.general/17802 12. http://article.gmane.org/gmane.comp.lang.haskell.general/17799 13. http://article.gmane.org/gmane.comp.lang.haskell.general/17791 14. http://article.gmane.org/gmane.comp.lang.haskell.general/17783 15. http://article.gmane.org/gmane.comp.lang.haskell.general/17779 16. http://article.gmane.org/gmane.comp.lang.haskell.general/17778 17. http://article.gmane.org/gmane.comp.lang.haskell.cafe/70188 18. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/70492 19. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/70450 20. http://planet.haskell.org/ 21. http://haskell.org/haskellwiki/Blog_articles 22. http://snoyberg.wordpress.com/2010/02/21/four-http-request-body-interfaces-… 23. http://byorgey.wordpress.com/2010/02/20/math-combinatorics-multiset/ 24. http://blog.darcs.net/2010/02/darcs-weekly-news-55.html 25. http://www.galois.com/blog/2010/02/19/tech-talk-modern-benchmarking-in-hask… 26. http://blog.malde.org/index.php/2010/02/19/tools-for-pyrosequencing-analysi… 27. http://archhaskell.wordpress.com/2010/02/19/arch-haskell-news-february-2010/ 28. http://donsbot.wordpress.com/2010/02/15/migrating-from-uvector-to-vector/ 29. http://ghcsparc.blogspot.com/2010/02/memory-barriers-and-ghc-6121.html 30. http://blog.darcs.net/2010/02/darcs-weekly-news-54.html 31. http://just-bottom.blogspot.com/2010/02/behind-dungeons.html 32. http://haskellformaths.blogspot.com/2010/02/how-to-find-strong-generating-s… 33. http://www.haskell.org/mailman/listinfo/haskell 34. http://sequence.complete.org/ 35. http://planet.haskell.org/ 36. http://sequence.complete.org/node/feed 37. http://haskell.org/ 38. http://haskell.org/haskellwiki/HWN 39. http://patch-tag.com/r/jfredett/HWN2/pullrepo%20HWN2

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