February 2009 - Haskell

Haskell Weekly News: Issue 106 - February 21, 2009
by Brent Yorgey 21 Feb '09

21 Feb '09

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20090221 Issue 106 - February 21, 2009 --------------------------------------------------------------------------- Welcome to issue 106 of HWN, a newsletter covering developments in the [1]Haskell community. Announcements HWEB. Eric Macaulay, following a little [2]prodding by Neil Mitchell, has released version 0 of [3]HWEB, a small tool for producing literate Haskell programs. Cabal-1.6.0.2 and cabal-install-0.6.2. Duncan Coutts [4]announced point-releases of the Cabal library and the cabal-install command line tool. These releases include a number of fixes and minor improvements, and are expected to be included with ghc-6.10.2. Barrie 0.3.1. Fraser Wilson [5]announced a hackage release of [6]Barrie, an implementation of an idea for supporting state based, user-driven GUIs. Yogurt-0.3. Martijn van Steenbergen [7]announced the release of [8]Yogurt-0.3, a MUD client library for Haskell. This version improves over 0.2 in several ways, including support for GHC 6.10, no more unsafeCoerce needed, new support for forking threads, and various refactorings. wxFruit-0.1.2. Henk-Jan van Tuyl [9]announced an [10]update of [11]wxFruit, a graphical user interface that combines some of the power and versatility of wxHaskell with the elegance and simplicity of Fruit. The new version works with GHC 6.10, and also includes a demo game, PaddleBall. Interested parties, take note: the position of developer/maintainer for this library is currently open. Paper draft: "Denotational design with type class morphisms". Conal Elliott [12]announced a [13]draft of a new paper, "Denotational design with type class morphisms". Feedback is appreciated, especially if in time for the March 2 ICFP deadline. Crypto 4.2.0 & Related News. Creighton Hogg [14]announced the release of version 4.2.0 of the [15]Crypto library. Creighton will also betaking over maintenance of the library from Dominic Steinitz. The Typeclassopedia, and request for feedback. Brent Yorgey [16]announced a [17]first draft of an article entitled 'The Typeclassopedia', a "starting point for the student of Haskell wishing to gain a firm grasp of its standard type classes." Comments and feedback are encouraged! hslibsvm-2.88.0.1 - A FFI binding to LibSVM. S. Guenther [18]announced the [19]hlibsvm package, a set of Haskell bindings to the C++ [20]libsvm library. spacepart-0.1.0.0 (was called data-spacepart). Corey O'Connor [21]announced a new release of the [22]spacepart package, supporting space-partitioning data structures. The new release includes many bug fixes and some code cleanup. pqueue-mtl, stateful-mtl. Louis Wasserman [23]announced two new packages, [24]stateful-mtl and [25]pqueue-mtl. stateful-mtl provides an ST monad transformer, several useful operations on generic monad transformers, and a monad transformer intended to cleanly externally wrap operations on a mutable array (including resizing operations). pqueue-mtl provides implementations of several structures supporting a generic 'single-in, single-out' paradigm (encapsulated in a typeclass named Queuelike), including stacks, queues, and several implementations of priority queues. haha-0.1 - Animated ascii lambda. Sebastiaan Visser [26]announced [27]haha, a very minimal vector based ascii art library written just for fun. If you've always wanted to have a full-color rotating vector based ascii art lambda on your terminal, now is your chance! Discussion Darcs and Google Summer of Code. Eric Kow [28]floated the idea of having darcs apply to the Google Summer of Code as a separate mentoring organization, and discussed several ideas for student projects. Jobs Postdoctoral Research Position at Yale University. Paul Hudak [29]announced the availability of a postdoctoral research position at Yale University. The successful candidate will apply modern, high-level programming language ideas (such as embodied in Haskell) to help design and implement a language for the control of BGP-based network routers, with the goal of realizing high-level networking protocols for traffic engineering, security, and related networking concerns. Blog noise [30]Haskell news from the [31]blogosphere. * GHC / OpenSPARC Project: [32]Triage. * Manuel M T Chakravarty: [33]Mark your Haskell tweets with #haskell. * Gregg Reynolds: [34]Performance Economics. * Alex Mason: [35]AVar released (three times). * Sean Leather: [36]The strict danger of switching from pure to monadic Template Haskell. * Mads Lindstrom: [37]Using Mutable Arrays for Faster Sorting. * Conal Elliott: [38]Denotational design with type class morphisms. A draft of Conal's new paper. * Jesse Andrews: [39]Getting Tiled with XMonad. * happstack.com: [40]SOCALFP Presentation Slides: "Happstack is better than X". * Luke Palmer: [41]Dependent types are ridiculously easy. * GHC / OpenSPARC Project: [42]Thunderbirds are go. * Brent Yorgey: [43]Typeclassopedia---a generic response. * Alex Mason: [44]ASTM updates. * London Haskell Users Group: [45]Lemmih: LHC - past, present and future. * Eric Kow (kowey): [46]announcing: burrito tutorial support group. Laden with burrito tutorial guilt? The burrito tutorial support group can help. * Alex Mason: [47]ASTM: redundant STMish fun. * happstack.com: [48]Announcing the launch of the Patch-Tag blog. * Colin Ross: [49]XML parsing with Haskell. * Brent Yorgey: [50]The Typeclassopedia---request for feedback. * Sean Leather: [51]Incremental fold, a design pattern. * Manuel M T Chakravarty: [52]Comparison of type families with functional dependencies.. A nice summary comparison of these two Haskell language features. * Random permutations and sorting: [53]Heinrich Apfelmus. * A day with xmonad: [54]Colin Adams. * Antoine Latter: [55]MaybeT - The CPS Version. * Gregg Reynolds: [56]Intergalactic Telefunctors and Quantum Entanglement. * Gregg Reynolds: [57]In Praise of Elitism. * Dan Piponi (sigfpe): [58]Beyond Monads. A generalization of monads to parameterized monads. * Well-Typed.Com: [59]Cabal ticket #500. Quotes of the Week * KetilMalde: No, those are quite outdated by now. The new horsemen of the programming apocalypse are, of course, IO, MutableState, LazyMemoryLeak, and Bottom. * skorpan: i love the layout of lyah. makes me feel like having some chunky bacon. * lilac: * lilac looks forward to Cale explaining category theory by analogy to Call of Duty * byorgey: _|_ ... is a party pooper * idnar: enlarge your context in just seven days with all-natural herbal supplements! * mmorrow: gah, i'm so used to haskell i forgot a return stmt in C and was trying to figure out where the segfault was happening for 20 minutes About the Haskell Weekly News New editions are posted to [60]the Haskell mailing list as well as to [61]the Haskell Sequence and [62]Planet Haskell. [63]RSS is also available, and headlines appear on [64]haskell.org. To help create new editions of this newsletter, please see the information on [65]how to contribute. Send stories to byorgey at cis dot upenn dot edu. The darcs repository is available at darcs get [66]http://code.haskell.org/~byorgey/code/hwn/ . References 1. http://haskell.org/ 2. http://neilmitchell.blogspot.com/2009/01/small-scripts-with-haskell.html 3. http://mathmeth.com/eem/hweb/quickstart.shtml 4. http://www.haskell.org//pipermail/haskell-cafe/2009-February/056153.html 5. http://article.gmane.org/gmane.comp.lang.haskell.general/16882 6. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/barrie 7. http://article.gmane.org/gmane.comp.lang.haskell.general/16869 8. http://code.google.com/p/yogurt-mud/ 9. http://article.gmane.org/gmane.comp.lang.haskell.cafe/53341 10. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/wxFruit 11. http://www.haskell.org/haskellwiki/WxFruit 12. http://article.gmane.org/gmane.comp.lang.haskell.cafe/53166 13. http://conal.net/papers/type-class-morphisms/ 14. http://article.gmane.org/gmane.comp.lang.haskell.cafe/53029 15. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Crypto 16. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52964 17. http://www.cis.upenn.edu/~byorgey/papers/typeclassopedia-draft-090216.pdf 18. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52961 19. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hslibsvm 20. http://www.csie.ntu.edu.tw/~cjlin/libsvm/ 21. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52951 22. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/spacepart 23. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52920 24. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/stateful%2Dmtl 25. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pqueue%2Dmtl 26. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52865 27. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haha 28. http://www.haskell.org//pipermail/haskell-cafe/2009-February/056057.html 29. http://article.gmane.org/gmane.comp.lang.haskell.cafe/53103 30. http://planet.haskell.org/ 31. http://haskell.org/haskellwiki/Blog_articles 32. http://ghcsparc.blogspot.com/2009/02/triage.html 33. http://justtesting.org/post/80211621 34. http://syntax.wikidot.com/blog:10 35. http://axman6.homeip.net/blog/2009/02/avar-released.html 36. http://feedproxy.google.com/~r/splonderzoek/~3/sD_bp8yKBxc/strict-danger-of… 37. http://lindstroem.wordpress.com/2009/02/19/using-mutable-arrays-for-faster-… 38. http://conal.net/blog/posts/denotational-design-with-type-class-morphisms/ 39. http://overstimulate.com/articles/why-xmonad 40. http://blog.happstack.com/2009/02/18/socalfp-presentation-slides-happstack-… 41. http://lukepalmer.wordpress.com/2009/02/18/dependent-types-are-ridiculously… 42. http://ghcsparc.blogspot.com/2009/02/thunderbirds-are-go.html 43. http://byorgey.wordpress.com/2009/02/17/typeclassopedia-a-generic-response/ 44. http://axman6.homeip.net/blog/2009/02/astm-updates.html 45. http://www.londonhug.net/2009/02/17/lemmih-lhc-past-present-and-future/ 46. http://koweycode.blogspot.com/2009/02/announcing-burrito-tutorial-support.h… 47. http://axman6.homeip.net/blog/2009/02/astm-redundant-stmish-fun.html 48. http://blog.happstack.com/2009/02/16/announcing-the-launch-of-the-patch-tag… 49. http://vcolin.com/2009/02/16/xml-parsing-haskell/ 50. http://byorgey.wordpress.com/2009/02/16/the-typeclassopedia-request-for-fee… 51. http://feedproxy.google.com/~r/splonderzoek/~3/tj_MkKqIlkQ/incremental-fold… 52. http://justtesting.org/post/78667708 53. http://apfelmus.nfshost.com/random-permutations.html 54. http://colina.demon.co.uk/?q=node/534 55. http://panicsonic.blogspot.com/2009/02/maybet-cps-version.html 56. http://syntax.wikidot.com/blog:9 57. http://syntax.wikidot.com/blog:8 58. http://blog.sigfpe.com/2009/02/beyond-monads.html 59. http://blog.well-typed.com/2009/02/cabal-ticket-500/ 60. http://www.haskell.org/mailman/listinfo/haskell 61. http://sequence.complete.org/ 62. http://planet.haskell.org/ 63. http://sequence.complete.org/node/feed 64. http://haskell.org/ 65. http://haskell.org/haskellwiki/HWN 66. http://code.haskell.org/~byorgey/code/hwn/

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(CfP) UML&AADL'2009 CfP : EXTENDED DEADLINE
by Isabelle Perseil 21 Feb '09

21 Feb '09

********************************************************************** CALL FOR PAPERS: UML&AADL2009 http://www.artist-embedded.org/artist/UML-AADL-2009.html Workshop held in conjunction with ICECCS 2009 The fourteenth IEEE International Conference on Engineering of Complex Computer Systems http://www.iceccs.org/ June 02, 2009 Potsdam, Germany ************************************************************************ Submission deadline: March 1st, 2009 -------------------------------------- Topics ====== New real-time systems have increasingly complex architectures because of the intricacy of the multiple interdependent features they have to manage. They must meet new requirements of reusability, interoperability, flexibility and portability. These new dimensions favor the use of an architecture description language that offers a global vision of the system, and which is particularly suitable for handling real-time characteristics. Due to the even more increased complexity of distributed, real-time and embedded systems (DRE), the need for a model-driven approach is more obvious in this domain than in monolithic RT systems. The purpose of this workshop is to provide an opportunity to gather researchers and industrial practitioners to survey existing efforts related to behavior modeling and model-based analysis of DRE systems. This workshop seeks contributions from researchers and practitioners interested in all aspects of the representation, analysis, and implementation of DRE system behavior and/or architecture models. To this end, we solicit papers (no more than 6 pages long) related to, but not limited to, the following principal topics: - Multi-domain specific modeling languages - Model transformation and generative approaches - Model-based Methodologies - Integration of different formalisms (e.g., Simulink/StateFlow, StateMate and Scade-drive) - Model Checking of architecture specifications - ADLs behavioral models simulation, Scheduling analysis and Worst-case execution time prediction Workshop Format =============== This full-day workshop will consist of an introduction of the topic by the workshop organizers, presentations of accepted papers, and in depth discussion of previously identified subjects emerging from the submissions. A summary of the discussions will be made available. Submission and Publication ========================== To contribute, please send a position paper or a technical paper to agusti[dot]canals[at]c-s[dot]fr with ICECCS09 UML&AADL Workshop in the title. Papers should not exceed 6 pages. Submitted manuscripts should be in English and formatted in the style of the IEEE Computer Society Proceedings Format. Preferably, submissions should be in PDF format. All selected papers will be published in the IEEE Computer Society Press Proceedings. IMPORTANT DATES =============== Submission deadline: March 01, 2009 All Notification of acceptance: March 05, 2009 Workshop date: June 02, 2009 Organizational sponsors ======================= ARTIST NoE OMG Organizers and Programme Steering Committee =========================================== Jean-Michel Bruel (IRIT, France) Agusti Canals (CS, France) Robert de Simone (INRIA, France) Sébastien Gérard (CEA-LIST, France) Isabelle Perseil (TELECOM ParisTech, France) Publicity Chair =============== Sun Meg (CWI, The Netherlands) IEEE CS TCCX Coordinator ======================== Mike Hinchey (NASA GSFC and Loyola College in Maryland, USA) Programme Committee =================== Yamine Ait Ameur (LISI / ENSMA, France) Keijiro Araki (Kyushu University, Japan) Grady Booch (IBM Fellow, USA) Agusti Canals (CS, France) Juan Antonio de la Puente (Universidad Politécnica de Madrid, Spain) Sebastien Demathieu (THALES, France) Dionisio De Niz Villasenor (SEI, Carnegie Mellon, USA) Vincent Englebert (University of Namur, Belgium) Madeleine Faugère (THALES, France) Mamoun Filali (IRIT, France) Robert France (Colorado State University, USA) Sébastien Gérard (CEA-LIST, France) Patrick Heymans (University of Namur, Belgium) Irfan Hamid (Microsoft Corp, Canada) J.J.M. Hooman (Embedded Systems Institute, The Netherlands) Bruce Lewis (US Army AMCOM) Johan Lilius (Åbo Akademi University, Finland) Ricardo J. Machado (University of Minho, Portugal) Sun Meg (CWI, The Netherlands) Dominique Mery (LORIA, France) Nenad Medvidovic (University of Southern California, USA) Thierry Millan (IRIT, France) Richard Paige (University of York, United Kingdom) Marc Reynolds (University of Western Australia, Australia) José Raúl Romero Salguero (Universidad de Córdoba, Spain) Bernhard Rumpe (Braunschweig University of Technology, Germany) Douglas C. Schmidt (Vanderbild University, USA) Françoise Simonot Lion (LORIA, France) Oleg Sokolsky (University of Pennsylvania, USA) Roy Sterritt (University of Ulster, United Kingdom) Jörn Guy Süß ( University of Queensland, Australia) Jing Sun (University of Auckland, New Zealand) Bedir Tekinerdogan (Bilkent University, Turkey) Martin Törngren (KTH - Royal Institute of Technology, Sweden) Laurence Tratt (Bournemouth University, United Kingdom) Tullio Vardanega (University of Padua, Italy) François Vernadat (CNRS-LAAS, France) Thomas Vergnaud (THALES, France) Eugenio Villar (Universidad de Cantabria, Spain) Sergio Yovine (CNRS-Verimag, France) Roberto V. Zicari (Goethe University Frankfurt, Germany)

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ANNOUNCE: wxFruit-0.1.2
by Henk-Jan van Tuyl 20 Feb '09

20 Feb '09

L.S., I have updated wxFruit to work with GHC 6.10; it can be downloaded from Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/wxFruit wxFruit is a graphical user interface that combines some of the power and versatility of wxHaskell with the elegance and simplicity of Fruit. The interface of wxFruit has a functional style, using arrows, whereas wxHaskell has an object oriented style. The package includes a demo game, PaddleBall: try to keep the ball in the game, using the mouse to move the paddle. The position of developer/maintainer is currently open. See also http://www.haskell.org/haskellwiki/WxFruit -- Regards, Henk-Jan van Tuyl -- http://functor.bamikanarie.com http://Van.Tuyl.eu/ --

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ANNOUNCE: Cabal-1.6.0.2 and cabal-install-0.6.2
by Duncan Coutts 19 Feb '09

19 Feb '09

I'm pleased to announce point-releases of the Cabal library and the cabal-install command line tool. If you are already using cabal-install then you can upgrade both using: $ cabal update $ cabal install Cabal cabal-install New users you can get it from: http://haskell.org/cabal/download.html For users on unix systems there is a source tarball with a bootstrap script. For users on Windows systems there is a pre-compiled cabal.exe. Release notes ============= Cabal-1.6.0.2 ------------- This is a point-release in the stable 1.6.x series. It is expected that this release will be included with ghc-6.10.2. It has a number of fixes and minor improvements. The most noticeable change is that Cabal now checks at configure time that C libraries and header files are available. This is known to break a small number of packages. The maintainers of these packages have been notified. Changes since 1.6.0.1: * New configure-time check for C headers and libraries * Added language extensions present in ghc-6.10 * Added support for NamedFieldPuns extension in ghc-6.8 * Fix in configure step for ghc-6.6 on Windows * Fix warnings in Path_pkgname.hs module on Windows * Fix for exotic flags in ld-options field * Fix for using pkg-config in a package with a lib and an executable * Fix for building haddock docs for exes that use the Paths module * Fix for installing header files in subdirectories * Fix for the case of building profiling libs but not ordinary libs * Fix read-only attribute of installed files on Windows * Ignore ghc -threaded flag when profiling in ghc-6.8 and older cabal-install-0.6.2 ------------------- This release contains a number of incremental improvements, including some new features. We expect to do another 0.6.x release in the not too distant future focusing on improvements in the way package dependencies are selected. Changes since 0.6.0: * The upgrade command has been disabled in this release * The configure and install commands now have consistent behaviour * Reduce the tendency to re-install already existing packages * The --constraint= flag now works for the install command * New --preference= flag for soft constraints / version preferences * Improved bootstrap.sh script, smarter and better error checking * New cabal info command to display detailed info on packages * New cabal unpack command to download and untar a package * HTTP-4000 package required, should fix bugs with http proxies * Now works with authenticated proxies. * On Windows can now override the proxy setting using an env var * Fix compatibility with config files generated by older versions * Warn if the hackage package list is very old * More helpful --help output, mention config file and examples * Better documentation in ~/.cabal/config file * Improved command line interface for logging and build reporting * Minor improvements to some messages Changes since 0.5.2: * Constraint solver can now cope with base 3 and base 4 * Allow use of package version preferences from hackage index * More detailed output from cabal install --dry-run -v * Improved bootstrap.sh Bugs and feature requests ========================= This is an excellent opportunity to make sure your favourite bug or feature request is properly described in our bug tracker: http://hackage.haskell.org/trac/hackage/ To help us guide development priorities please add yourself to the ticket's cc list and describe why that bug or feature is important to you. Credits ======= On behalf of the Cabal hackers and the community generally I'd like to thank the people who have contributed patches for these releases: * Gleb Alexeyev * Samuel Bronson * Thomas Schilling * Ganesh Sittampalam * Andrea Vezzosi Get involved ============ There's still a lot to do! We have big plans for Cabal-2.0, cabal-install and the Hackage website. So if you're interested in helping out with this core infrastructure project then: * subscribe to the cabal-devel mailing list: http://www.haskell.org/mailman/listinfo/cabal-devel * grab the source: http://haskell.org/cabal/code.html * read the guide to the source code: http://hackage.haskell.org/trac/hackage/wiki/SourceGuide * take a look at our list of bugs and feature requests: http://hackage.haskell.org/trac/hackage/report/12 especially the easy tickets: http://hackage.haskell.org/trac/hackage/report/13 Duncan

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ANN: Barrie 0.3.1
by Fraser Wilson 17 Feb '09

17 Feb '09

This is the hackaged version of an earlier release of Barrie. This release is not backward compatible (but it took me about five minutes to update everything). >From the package description: Implementation of an idea for supporting certain kinds of GUI: that is state based, user-driven ones. The GUI is intended to manipulate a state, and it is responsive rather than active. Configuration is an example. The idea is that you already have a state-manipulation bit of code lying around, and you want to slap a GUI on the front. Barrie does not help you write beautiful code, but it sure puts something functional on the screen quickly. It's currently being used for an interface to a Bridge application, and for something else which is too nerdy to describe here, but which follows the general pattern of the intended purpose. To install: $ cabal update $ cabal install barrie Barrie now requires gtk2hs 0.10.0. <http://hackage.haskell.org/cgi-bin/hackage-scripts/package/barrie>Changes: - Dropped the generic value type. It was 1. not type safe 2. not interesting 3. not exactly everything I ever wanted from a type-agnostic storage mechanism. Instead, Barrie operates internally with Strings. This should be type safe because of the way they are wrapped, and it seems like a good place to park the problem until I work out what I really want. - Gadget constructors are now much more regular. For example, to create a gadget that displays things, you have a choice of displayG, which displays any instance of show, displayG', which lets you provide your own conversions to and from String, and textDisplayG, which displays plain old Strings. Similarly, the chooserG gadget is created by chooserG, chooserG' and textChooserG, but there's also enumChooserG, which automatically creates a chooser for the elements of any Enum that is an instance of Show. Choosers can currently be rendered by a list or a combo box. - Quite a bit of documentation, which, because of the regularity imposed by Haddock, is making me question the decision to use Literate Haskell. Hey ho, live and learn. - Text boxes now apply their changes after they lose focus. The darcs repository with demos can still be found at http://thewhitelion.org/darcs/barrie, and I think I've sorted out the recent problems there. cheers, Fraser. -- http://thewhitelion.org/mysister

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Haskell Weekly News: Issue 105 - February 17, 2009
by Brent Yorgey 17 Feb '09

17 Feb '09

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20090217 Issue 105 - February 17, 2009 --------------------------------------------------------------------------- Welcome to issue 105 of HWN, a newsletter covering developments in the [1]Haskell community. And here's the Belated Valentine's Day HWN! Motto: "Remembering that you love someone three days after you were supposed to is better than not remembering at all." Of course, it's late because I spent the weekend working on the Typeclassopedia (although you won't find a link to it in this HWN because I've only included things through Saturday). Much Haskell love to all! Announcements Plans for GHC 6.10.2. Ian Lynagh [2]announced a quick summary of the plans for GHC 6.10.2. If there is a bug not on the [3]high-priority list that is causing you major problems, please let the developers know. A release candidate is expected to be ready by the end of the week. Bug fix to regex-tdfa, new version 0.97.3. ChrisK [4]announced a [5]new release of regex-tdfa which fixes some additional bugs. Three Cheers For QuickCheck! Google Summer of Code 2009. Malcolm Wallace [6]announced that haskell.org will once again be applying to be a Google Summer of Code mentor organization. Now is the time to begin discussing ideas for student projects. Also, if you wish to help publicize GSoC amongst students, there are [7]official posters/fliers available. A long discussion of various project ideas followed, including some analysis of the factors which contribute to project success. happs-tutorial 0.7. Creighton Hogg [8]announced the release of [9]happs-tutorial 0.7, the first release of happs-tutorial built against the new [10]Happstack project. Creighton has now taken over development of the tutorial from Thomas Hartman. first Grapefruit release. Wolfgang Jeltsch [11]announced the first official release of [12]Grapefruit, a library for Functional Reactive Programming (FRP) with a focus on user interfaces. With Grapefruit, you can implement reactive and interactive systems in a declarative style. User interfaces are described as networks of communicating widgets and windows. Communication is done via different kinds of signals which describe temporal behavior. CFP: 5th Haskell Hackathon, April 17-19, Utrecht. Sean Leather [13]issued a call for participation in the [14]5th Haskell Hackathon, which will be held in Utrecht, The Netherlands, from 17-19 April. The Haskell Hackathon is a collaborative coding festival with a simple focus: build and improve Haskell libraries, tools, and infrastructure. All are welcome! See the website for more information, or join the IRC channel (#haskell-hac5). Please register if you plan to attend! Take a break: write an essay for Onward! Essays. Simon Peyton-Jones [15]announced a call for submissions to [16]Onward! Essays. An Onward! essay is a thoughtful reflection upon software-related technology. Its goal is to help the reader to share a new insight, engage with an argument, or wrestle with a dilemma. The deadline is 20 April. Data.Stream 0.3. Wouter Swierstra [17]announced a new version of the [18]Data.Stream package, a modest library for manipulating infinite lists. Changes include support for lazy SmallCheck, an improved Show instance, stricter scans, various documentation fixes, and several new functions from Data.List. X Haskell Bindings 0.1. Antoine Latter [19]announced a new release of the [20]X Haskell Bindings (XHB) library. The goal of XHB is to provide a Haskell implementation of the X11 wire protocol, similar in spirit to the X protocol C-language Binding (XCB). Gtk2HS 0.10.0 released. Peter Gavin [21]announced a [22]new release of [23]Gtk2HS, the Haskell GTK bindings. Notable changes include support for GHC 6.10, bindings to GIO and GtkSourceView-2.0, a full switch to the new model-view implementation using a Haskell model, and many others. Discussion Haskell.org GSoC. Daniel Kraft began a [24]discussion about good topics for a Haskell GSoC project. Painting logs to get a coloured tree. Joachim Breitner asked about elegant ways to annotate trees, leading to an interesting [25]discussion. Blog noise [26]Haskell news from the [27]blogosphere. * Conor McBride: [28]FP Lunch: Djinn, monotonic. * Gregg Reynolds: [29]"Computation" considered harmful. "Value" not so hot either.. * Darcs: [30]darcs weekly news #17. * Antoine Latter: [31]Dependencies in Hackage, revisited. * GHC / OpenSPARC Project: [32]Allocate!. * Chris Done: [33]Updates: RSS and highlighting. * Chris Done: [34]Simple SMTP library with plain/login authentication. * The GHC Team: [35]Ever wondered how big a closure is?. * Luke Palmer: [36]Dana update: Core execution language, dependent combinators. * John Van Enk: [37]Distraction: Fun with diagrams!. * Magnus Therning: [38]New backend for epilicious pushed.. * Alex Mason: [39]Shootout PiDigits program kinda sucks (and possibly so does GHC). * Gtk2HS: [40]Gtk2Hs version 0.10.0 released. * Ketil Malde: [41]Notes from PADL. * Alson Kemp: [42]Kudos to Bodo. * xmonad: [43]New layout: XMonad.Layout.Cross. * Gregg Reynolds: [44]Programming Language Semiotics. * Gregg Reynolds: [45]Formal semantics for side effects. * xmonad: [46]contribs review: CycleWindows, multimedia keys, runOrCopy. * Conal Elliott: [47]From the chain rule to automatic differentiation. * Arnar Birgisson: [48]The Non-Determinism Monad. * Matthew Jones: [49]XMonad: A tiling window manager written in Haskell. * Gregg Reynolds: [50]Moggi :: CT -> Hask. * Lennart Augustsson: [51]More BASIC. Quotes of the Week * chrisdone: zipWith3 ($) (cycle [const,flip const]) "hai! haha!" "yarlysotense!" * quicksilver: I'm very unlikely to give the time of day to anything which doesn't let me continue to use emacs. * roconnor: don't let Float do your finance homework for you. * quicksilver: @go is made of STRING and FAIL. * drhodes: We're sorry Mr. Thunk, but this program is on a need to run basis, and you don't need to run. Now go away before I call the garbage collector. About the Haskell Weekly News New editions are posted to [52]the Haskell mailing list as well as to [53]the Haskell Sequence and [54]Planet Haskell. [55]RSS is also available, and headlines appear on [56]haskell.org. To help create new editions of this newsletter, please see the information on [57]how to contribute. Send stories to byorgey at cis dot upenn dot edu. The darcs repository is available at darcs get [58]http://code.haskell.org/~byorgey/code/hwn/ . References 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.glasgow.user/16304 3. http://hackage.haskell.org/trac/ghc/query?status=new&status=assigned&status… 4. http://article.gmane.org/gmane.comp.lang.haskell.general/16859 5. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-tdfa 6. http://article.gmane.org/gmane.comp.lang.haskell.general/16857 7. http://code.google.com/p/google-summer-of-code/wiki/GsocFlyers 8. http://article.gmane.org/gmane.comp.lang.haskell.general/16848 9. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/happs-tutorial 10. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/happs-tutorial 11. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52847 12. http://haskell.org/haskellwiki/Grapefruit 13. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52689 14. http://haskell.org/haskellwiki/Hac5 15. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52660 16. http://onward-conference.org/calls/foressays 17. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52558 18. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Stream/ 19. http://article.gmane.org/gmane.comp.lang.haskell.cafe/52364 20. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xhb 21. http://www.haskell.org//pipermail/haskell-cafe/2009-February/055490.html 22. https://sourceforge.net/project/showfiles.php?group_id=49207package_id=4244… 23. http://www.haskell.org/gtk2hs/ 24. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/52553 25. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/52461 26. http://planet.haskell.org/ 27. http://haskell.org/haskellwiki/Blog_articles 28. http://sneezy.cs.nott.ac.uk/fplunch/weblog/?p=187 29. http://syntax.wikidot.com/blog:5 30. http://blog.darcs.net/2009/02/news-and-discussions-1_13.html 31. http://panicsonic.blogspot.com/2009/02/dependencies-in-hackage-revisited.ht… 32. http://ghcsparc.blogspot.com/2009/02/allocate.html 33. http://chrisdone.com/blog/html/2009-02-13-lang-spec-tag-rss.html 34. http://chrisdone.com/blog/html/2009-02-13-smtp.html 35. http://ghcmutterings.wordpress.com/2009/02/12/53/ 36. http://lukepalmer.wordpress.com/2009/02/12/dana-update-core-execution-langu… 37. http://blog.sw17ch.com/wordpress/?p=18 38. http://therning.org/magnus/archives/499 39. http://axman6.homeip.net/blog/2009/02/shootout-pidigits-program-kinda-sucks… 40. http://haskell.org/gtk2hs/archives/2009/02/11/gtk2hs-version-0100-released/ 41. http://blog.malde.org/index.php/2009/02/11/notes-from-padl/ 42. http://www.alsonkemp.com/haskell/kudos-to-bodo/ 43. http://xmonad.wordpress.com/2009/02/10/new-layout-xmonadlayoutcross/ 44. http://syntax.wikidot.com/blog:4 45. http://syntax.wikidot.com/blog:3 46. http://xmonad.wordpress.com/2009/02/08/contribs-review-cyclewindows-multime… 47. http://conal.net/blog/posts/from-the-chain-rule-to-automatic-differentiatio… 48. http://www.hvergi.net/2009/02/the-non-determinism-monad/ 49. http://matburt.net/?p=36 50. http://syntax.wikidot.com/blog:1 51. http://augustss.blogspot.com/2009/02/more-basic-not-that-anybody-should-car… 52. http://www.haskell.org/mailman/listinfo/haskell 53. http://sequence.complete.org/ 54. http://planet.haskell.org/ 55. http://sequence.complete.org/node/feed 56. http://haskell.org/ 57. http://haskell.org/haskellwiki/HWN 58. http://code.haskell.org/~byorgey/code/hwn/

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ANN: The Typeclassopedia, and request for feedback
by Brent Yorgey 17 Feb '09

17 Feb '09

Hi all, If you've noticed the lack of a HWN this week, that's because I've been doggedly finishing my article entitled 'The Typeclassopedia', which I have just submitted for publication in the Monad.Reader. Here's the abstract: The standard Haskell libraries feature a number of type classes with algebraic or categorical underpinnings. Becoming a fluent Haskell hacker requires intimate familiarity with them all, yet acquiring this familiarity often involves combing through a mountain of tutorials, blog posts, mailing list archives, and IRC logs. The goal of this article is to serve as a starting point for the student of Haskell wishing to gain a firm grasp of its standard type classes. The essentials of each type class are introduced, with examples, commentary, and extensive references for further reading. My hope is that this will be a valuable resource to the Haskell community, especially those who are learning. Any feedback would be greatly appreciated, especially if it helps improve the article before publication. A draft can be found here: http://www.cis.upenn.edu/~byorgey/papers/typeclassopedia-draft-090216.pdf Also see my blog post for a bit more info: http://byorgey.wordpress.com/2009/02/16/the-typeclassopedia-request-for-fee… happy haskelling! -Brent

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ANN : Crypto 4.2.0 & Related News
by Creighton Hogg 17 Feb '09

17 Feb '09

Hello Haskellers, I'm pleased to announce version 4.2.0 of Crypto has been uploaded to Hackage & that I am taking over maintenance of the library from Dominic Steinitz. As of this release it should be cabal install'able on GHC 6.10.1. I'm also pleased to announce that the darcs repo will be moving from code.haskell.org to being hosted on Patch-Tag at http://patch-tag.com/repo/crypto/home. You don't need to sign up for Patch-Tag to use the read only repos, but you will need an account if you want to be given write access to the crypto repository. Please feel free to e-mail me with any issues or questions. Cheers, Creighton

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Ann: Yogurt-0.3
by Martijn van Steenbergen 16 Feb '09

16 Feb '09

Dear Haskellers, I'm pleased to announce the release of Yogurt-0.3! This version improves over 0.2 in several ways: * It compiles and runs with GHC 6.10. * The Mud monad is now built on top of IO. * Vars are expressed as IORefs. No more unsafeCoerce needed. * Forking of threads is supported, with callback into the Mud monad: > type RunMud = forall a. Mud a -> IO a > forkWithCallback :: (RunMud -> IO ()) -> Mud ThreadId * Timers are no longer a primitive: they can be expressed as function of forkWithCallback. * Refactorings in the architecture: the features are a strict superset of the previous version while the number of lines of code has decreased by 10%. All feedback is appreciated! Thanks to Saizan on #haskell for helping me work around the predicative types. :-) The code is available at Google: http://code.google.com/p/yogurt-mud/ Kind regards, Martijn.

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ANNOUNCE: first Grapefruit release
by Wolfgang Jeltsch 14 Feb '09

14 Feb '09

Dear friends of Haskell and Functional Reactive Programming, its my pleasure to announce the first official release of Grapefruit, a library for Functional Reactive Programming (FRP) with a focus on user interfaces. With Grapefruit, you can implement reactive and interactive systems in a declarative style. User interfaces are described as networks of communicating widgets and windows. Communication is done via different kinds of signals which describe temporal behavior. Grapefruit consists of five packages with several interesting features: grapefruit-frp: Functional Reactive Programming core * The FRP implementation uses a hybrid push/pull-based approach. * Signals can be memoized by binding them to variables – like ordinary data structures. * Merging of event streams combines simultaneous events properly. * Signals cannot behave differently by starting them at different times. The type system is used to enforce proper aging of signals. grapefruit-records: A record system for Functional Reactive Programming * Input records can specify fields as being required or optional. * Uninteresting output fields can be ignored. The set of interesting fields is specified by pattern matching. grapefruit-ui: Declarative user interface programming * The interface for UI programming is platform-independent and can be implemented on top of different UI toolkits. * A concrete implementation can be selected at compile time or runtime. grapefruit-ui-gtk: GTK+-based implementation of the general UI interface * Gtk2Hs is used internally. grapefruit-examples: examples demonstrating features of Grapefruit * Circular communication and switching are demonstrated. Support for the following is planned for the future: * signals with incremental updates * user interfaces with changing structure * more kinds of UI components * graphical animations Further information about Grapefruit is available on its wiki page at <http://haskell.org/haskellwiki/Grapefruit>. If you have questions, applause or criticism, please get in touch with me. Wolfgang Jeltsch Principal Grapefruit developer

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