September 2011 - Haskell

ANN: usb-1.0, bindings-libusb-1.4.4 and usb-iteratee-0.4
by Bas van Dijk 18 Sep '11

18 Sep '11

Fellow Haskellers, I would like to announce the 1.0 release of the usb library! This library lets you to communicate with USB devices from userspace. It is implemented as a high-level wrapper around bindings-libusb[1] which is a low-level binding to the portable C library: libusb-1.0 ( http://libusb.org ). I think a 1.0 release is warranted since I have been successfully using the library in an industrial application at Sensor Sense for some time now. This release also adds the last piece of functionality that was missing from previous releases: isochronous transfers. These let you communicate with USB video or audio devices for example. A second major change is that all I/O functions, while still having a synchronous interface (they block), are now implemented asynchronously. This makes them more efficient (no busy-loops) and interruptible (just throw an asynchronous exception to the thread executing a transfer and the transfer is automatically canceled). The implementation uses the GHC event manager for event handling. If the event manager is not available, because you're either: not using GHC, building your program without -threaded or you're on Windows the implementation degrades gracefully to the synchronous implementation. Other changes: * Added writeControlExact :: DeviceHandle -> ControlAction WriteExactAction. * All I/O functions which previously returned the boolean TimedOut now return a: data Status = Completed | TimedOut. * Added the timeout constant: noTimeout :: Timeout. * Added function: maxIsoPacketSize :: EndpointDesc -> Size Which calculates the maximum packet size which a specific endpoint is capable of sending or receiving in the duration of 1 microframe. This function is mainly useful for setting up isochronous transfers. * Added some specific IOExceptions: ioException :: USBException incompleteReadException :: USBException incompleteWriteException :: USBException * Renamed System.USB.IO.Synchronous to just System.USB.IO. * Renamed System.USB.Unsafe to System.USB.Internal and exported more functions from it which are primarily needed in the usb-iteratee package. * Fixed some bugs. * Switched from darcs to git and hosted the project on github: https://github.com/basvandijk/usb/ API Docs: http://hackage.haskell.org/package/usb-1.0 Installing: $ cabal update $ cabal install usb I would like to thank John Obbele for pushing me to write the asynchronous implementation and for testing the library. Also thanks to Joris Putcuyps for testing the library on Windows. Unfortunately the library doesn't yet work on that platform due to a weird segmentation fault: http://hackage.haskell.org/trac/ghc/ticket/5254. Hopefully we will solve it in the near future. bindings-libusb =============== The usb library is based on bindings-libusb which is a low-level binding to the libusb C library. I recently took over maintenance of this package from Maurício Antunes. Maurício, thanks for creating and maintaining this package! It greatly simplified the task of writing the high-level wrapper. API Docs: http://hackage.haskell.org/package/bindings-libusb-1.4.4 usb-iteratee ============ I also released a new library: usb-iteratee which provides iteratee enumerators for the usb package. Note that this package was previously called usb-enumerator. However I'm planning to rewrite the latter to offer enumerators for the enumerator package instead. API Docs: http://hackage.haskell.org/package/usb-iteratee-0.4 Regards, Bas

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Ann: splaytree-0.1
by John Lato 16 Sep '11

16 Sep '11

Dear all, I am very pleased to announce the first release of splaytree. Splaytree provides splay tree based implementations of Sets, Seqs, and RangeSets. A RangeSet is similar to an IntervalSet, however as new ranges are inserted, they are combined with any existing ranges. This guarantees that the RangeSet consists of only non-overlapping ranges, and can be used to easily generate a list of non-overlapping ranges (read more at http://johnlato.blogspot.com/2011/09/splaytree-package-released.html) Absolute performance isn't a goal of this package, however according to my benchmarks it seems to be competitive with unordered-containers for many operations, although the worst-case complexity of a splay tree is O(n). http://hackage.haskell.org/package/splaytree repo: http://www.tiresiaspress.us/haskell/splaytree/ The design owes much to Ralf Hinze and Ross Paterson's excellent work on finger trees. John L.

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Haskell Weekly News: Issue 199
by Daniel Santa Cruz 15 Sep '11

15 Sep '11

Welcome to issue 199 of the HWN, a newsletter covering developments in the Haskell community. This release covers the week of September 4 to 10, 2011. Announcements Johannes Waldmann open the invitation to the 6th Haskell in Leipzig workshop, on October 7, 2011. It "will present an absolutely thrilling mixture of tutorials and talks, with special enphasis on parallel programming." [1] http://goo.gl/u0PwF New and Updated Projects * Hs2lib (Phyx; v-0.5.5) A preprocesor and library which allow you to create dynamic libs from arbitrary annotated Haskell programs with one click. It also allows you to use the generated lib in C, C++, and C# just by including the generated header files. [2] http://goo.gl/xCSXc * Netwire (Ertugrul Soeylemez; 1.2.0) Lots of new features! [3] http://goo.gl/VCwb1 * network-address (Sebastian Nowicki; 0.2.0) Provides data structures and textual representation of network addresses (IPv4, IPv6, subnets). [4] http://goo.gl/DBRI6 * Webrexp (Vincent Berthoux; 1.1) A web scraping command line utility. [5] http://goo.gl/OlovQ * eddie (Mike Meyer; 0.5) Is a tool for applying haskell filters to text files via the unix command line. [6] http://goo.gl/NPc0b * cabal-ghci (Etienne Laurin; 0.1) Package to ease the development of projects using cabal. [7] http://goo.gl/fiDKZ Quotes of the Week * gosu: Type parameters are covariant. This is not sound, and that does not matter. * turtlesalltheway: if haskell is so great why cant it improve itself * mm_freak: bosses are generally quite strong, static and lazy * cmccann: newtype Natural = N { denature :: Integer } Top Reddit Stories * Constraint Kinds for GHC Domain: blog.omega-prime.co.uk, Score: 115, Comments: 12 On Reddit: [8] http://goo.gl/bCXgf Original: [9] http://goo.gl/7aWzn * Yesod :: The Limitations of Haskell Domain: yesodweb.com, Score: 108, Comments: 42 On Reddit: [10] http://goo.gl/5q7wW Original: [11] http://goo.gl/gisIh * Frege: haskell like language on JVM (tries to adhere to haskell 2010 where possible) Domain: code.google.com, Score: 58, Comments: 58 On Reddit: [12] http://goo.gl/6KWEg Original: [13] http://goo.gl/56AkX * Sharing in Haskell – How the let and lambda constructs give a precise way to control sharing Domain: neilmitchell.blogspot.com, Score: 34, Comments: 18 On Reddit: [14] http://goo.gl/Uf1vq Original: [15] http://goo.gl/4Hmfu * Let's play a game : How to implement functions from their type signatures Domain: blog.ezyang.com, Score: 24, Comments: 13 On Reddit: [16] http://goo.gl/T2FiD Original: [17] http://goo.gl/SmbYO * Impredicativity + injectivity + type case analysis = inconsistency (Russell paradox) :: Oleg Domain: okmij.org, Score: 23, Comments: 10 On Reddit: [18] http://goo.gl/zoThI Original: [19] http://goo.gl/jFr5U * Functional Pearls Domain: haskell.org, Score: 23, Comments: 1 On Reddit: [20] http://goo.gl/RVyng Original: [21] http://goo.gl/1A7t0 * An EventSource broker written in Haskell Domain: mathias-biilmann.net, Score: 22, Comments: 0 On Reddit: [22] http://goo.gl/7yywu Original: [23] http://goo.gl/Y5mGj * Haskell For Kids: Week 4 Domain: cdsmith.wordpress.com, Score: 22, Comments: 2 On Reddit: [24] http://goo.gl/KwlqD Original: [25] http://goo.gl/xlNh2 * apfelmus - Vault - a persistent store for values of arbitrary types Domain: apfelmus.nfshost.com, Score: 19, Comments: 2 On Reddit: [26] http://goo.gl/VAE4n Original: [27] http://goo.gl/vvQ7A * Tau is available in Haskell, you can safely avoid Pi Domain: hackage.haskell.org, Score: 19, Comments: 26 On Reddit: [28] http://goo.gl/u5GN8 Original: [29] http://goo.gl/VnrMh * Zipper from any Traversable :: Oleg Domain: okmij.org, Score: 18, Comments: 2 On Reddit: [30] http://goo.gl/xi4ZF Original: [31] http://goo.gl/nqZ3T Top StackOverflow Questions * More on generic Scala functions votes: 20, answers: 4 Read on SO: [32] http://goo.gl/DGH14 * Why is a “type class” called “type class”? votes: 20, answers: 2 Read on SO: [33] http://goo.gl/YbVXX * Is there a Haskell idiom for updating a nested data structure? votes: 14, answers: 2 Read on SO: [34] http://goo.gl/jKEjv * How to tell if a list is infinite? votes: 14, answers: 4 Read on SO: [35] http://goo.gl/fc3e6 * Select random element from a set, faster than linear time (Haskell) votes: 9, answers: 5 Read on SO: [36] http://goo.gl/IRJf3 * GHC not optimising modules other than the main module votes: 9, answers: 0 Read on SO: [37] http://goo.gl/8Ephm * A chess board representation in Haskell votes: 8, answers: 4 Read on SO: [38] http://goo.gl/iSM7d * How to cap memory usage of Haskell threads votes: 7, answers: 2 Read on SO: [39] http://goo.gl/dvLnE * Is this Haskell type inference in action, or something else? votes: 7, answers: 2 Read on SO: [40] http://goo.gl/hTaK7 * Assymmetry in the bind function votes: 6, answers: 7 Read on SO: [41] http://goo.gl/KqMTn About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstcruz(a)gmail.com. Until next time, Daniel Santa Cruz References 1. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92287 2. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92182 3. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92225 4. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18916 5. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18929 6. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18930 7. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92279 8. http://blog.omega-prime.co.uk/?p=127 9. http://www.reddit.com/r/haskell/comments/kbf14/constraint_kinds_for_ghc/ 10. http://www.yesodweb.com/blog/2011/09/limitations-of-haskell 11. http://www.reddit.com/r/haskell/comments/k4lc4/yesod_the_limitations_of_has… 12. http://code.google.com/p/frege/ 13. http://www.reddit.com/r/haskell/comments/kadx6/frege_haskell_like_language_… 14. http://neilmitchell.blogspot.com/2011/09/sharing-in-haskell.html 15. http://www.reddit.com/r/haskell/comments/k4bq9/sharing_in_haskell_how_the_l… 16. http://blog.ezyang.com/2011/09/lets-play-a-game/ 17. http://www.reddit.com/r/haskell/comments/k5okh/lets_play_a_game_how_to_impl… 18. http://okmij.org/ftp/Haskell/impredicativity-bites.html 19. http://www.reddit.com/r/haskell/comments/k5bdb/impredicativity_injectivity_… 20. http://www.haskell.org/haskellwiki/Research_papers/Functional_pearls 21. http://www.reddit.com/r/haskell/comments/kb3w5/functional_pearls/ 22. http://mathias-biilmann.net/posts/2011/9/a-haskell-eventsource-broker 23. http://www.reddit.com/r/haskell/comments/k6fva/an_eventsource_broker_writte… 24. http://cdsmith.wordpress.com/2011/09/10/haskell-for-kids-week-4/ 25. http://www.reddit.com/r/haskell/comments/kbqn0/haskell_for_kids_week_4/ 26. http://apfelmus.nfshost.com/blog/2011/09/04-vault.html 27. http://www.reddit.com/r/haskell/comments/k4l6c/apfelmus_vault_a_persistent_… 28. http://hackage.haskell.org/package/tau 29. http://www.reddit.com/r/haskell/comments/kazfn/tau_is_available_in_haskell_… 30. http://okmij.org/ftp/continuations/zipper.html#traversable 31. http://www.reddit.com/r/haskell/comments/k5bci/zipper_from_any_traversable_… 32. http://stackoverflow.com/questions/7337582/more-on-generic-scala-functions 33. http://stackoverflow.com/questions/7360024/why-is-a-type-class-called-type-… 34. http://stackoverflow.com/questions/7365425/is-there-a-haskell-idiom-for-upd… 35. http://stackoverflow.com/questions/7371730/how-to-tell-if-a-list-is-infinite 36. http://stackoverflow.com/questions/7349080/select-random-element-from-a-set… 37. http://stackoverflow.com/questions/7367070/ghc-not-optimising-modules-other… 38. http://stackoverflow.com/questions/7309554/a-chess-board-representation-in-… 39. http://stackoverflow.com/questions/7297654/how-to-cap-memory-usage-of-haske… 40. http://stackoverflow.com/questions/7342222/is-this-haskell-type-inference-i… 41. http://stackoverflow.com/questions/7319424/assymmetry-in-the-bind-function

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Final CFP: PEPM12 - Workshop on Partial Evaluation and Program Manipulation
by oleg＠okmij.org 14 Sep '11

14 Sep '11

Final Call For Papers Paper submission deadline: Mon, October 10, 2011, 23:59, GMT ACM SIGPLAN 2012 Workshop on Partial Evaluation and Program Manipulation January 23-24, 2012. Philadelphia, Pennsylvania, USA (co-located with POPL'12) http://www.program-transformation.org/PEPM12 The PEPM Symposium/Workshop series aims to bring together researchers and practitioners working in the broad area of program transformation, which spans from refactoring, partial evaluation, supercompilation, fusion and other metaprogramming to model-driven development, program analyses including termination, inductive programming, program generation and applications of machine learning and probabilistic search. PEPM focuses on techniques, supporting theory, tools, and applications of the analysis and manipulation of programs. Each technique or tool of program manipulation should have a clear, although perhaps informal, statement of desired properties, along with an argument how these properties could be achieved. Topics of interest for PEPM'12 include, but are not limited to: - Program and model manipulation techniques such as: supercompilation, partial evaluation, fusion, on-the-fly program adaptation, active libraries, program inversion, slicing, symbolic execution, refactoring, decompilation, and obfuscation. - Program analysis techniques that are used to drive program/model manipulation such as: abstract interpretation, termination checking, binding-time analysis, constraint solving, type systems, automated testing and test case generation. - Techniques that treat programs/models as data objects including metaprogramming, generative programming, embedded domain-specific languages, program synthesis by sketching and inductive programming, staged computation, and model-driven program generation and transformation. - Application of the above techniques including case studies of program manipulation in real-world (industrial, open-source) projects and software development processes, descriptions of robust tools capable of effectively handling realistic applications, benchmarking. Examples of application domains include legacy program understanding and transformation, DSL implementations, visual languages and end-user programming, scientific computing, middleware frameworks and infrastructure needed for distributed and web-based applications, resource-limited computation, and security. To maintain the dynamic and interactive nature of PEPM, we will continue the category of `short papers' for tool demonstrations and for presentations of exciting if not fully polished research, and of interesting academic, industrial and open-source applications that are new or unfamiliar. Student attendants with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses and other support. All accepted papers, short papers included, will appear in formal proceedings published by ACM Press and will be included in the ACM Digital Library. Selected papers may later on be invited for a journal special issue dedicated to PEPM'12. Submission Categories and Guidelines Authors are strongly encouraged to consult the advice for authoring research papers and tool papers before submitting. The PC Chairs welcome any inquiries about the authoring advice. Regular research papers must not exceed 10 pages in ACM Proceedings style. Short papers are up to 4 pages in ACM Proceedings style. Authors of tool demonstration proposals are expected to present a live demonstration of the described tool at the workshop (tool papers should include an additional appendix of up to 6 extra pages giving the outline, screenshots, examples, etc. to indicate the content of the proposed live demo at the workshop). Important Dates - Paper submission: Mon, October 10, 2011, 23:59, GMT - Author notification: Tue, November 8, 2011 - Workshop: Mon-Tue, January 23-24, 2012 Invited Speakers - Markus Pueschel (ETH Zurich, Switzerland) - Martin Berger (University of Sussex, UK) Program Chairs - Oleg Kiselyov (Monterey, CA, USA) - Simon Thompson (University of Kent, UK) Program Committee Members - Emilie Balland (INRIA, France) - Ewen Denney (NASA Ames Research Center, USA) - Martin Erwig (Oregon State University, USA) - Sebastian Fischer (National Institute of Informatics, Japan) - Lidia Fuentes (Universidad de Malaga, Spain) - John Gallagher (Roskilde University, Denmark and IMDEA Software, Spain) - Dave Herman (Mozilla Research, USA) - Stefan Holdermans (Vector Fabrics, the Netherlands) - Christian Kaestner (University of Marburg, Germany) - Emanuel Kitzelmann (International Computer Science Institute, USA) - Andrei Klimov (Keldysh Institute of Applied Mathematics, Russian Academy of Sciences) - Shin-Cheng Mu (Academia Sinica, Taiwan) - Alberto Pardo (Universidad de la Repu'blica, Uruguay) - Kostis Sagonas (Uppsala University, Sweden and National Technical University of Athens, Greece) - Anthony M. Sloane (Macquarie University, Australia) - Armando Solar-Lezama (MIT, USA) - Aaron Stump (The University of Iowa, USA) - Kohei Suenaga (University of Kyoto, Japan) - Eric Van Wyk (University of Minnesota, USA) - Kwangkeun Yi (Seoul National University, Korea)

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Leipzig (Germany) Haskell Workshop 7 October - Program and Registration
by Janis Voigtländer 12 Sep '11

12 Sep '11

Dear all, On Friday, 7th October, this year's "Haskell in Leipzig" meeting takes place with tutorials (for Haskell beginners, for Scala beginners, on parallel Haskell) and exciting talks. A special emphasis this year is on parallel programming, with a tutorial by Andres Löh (Well-Typed) and a talk by Kevin Hammond (University of St. Andrews, Scotland; talk in English). More information on the website (with program and registration form): http://portal.imn.htwk-leipzig.de/events/hal6-haskell-workshop Best, Janis. -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

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ANN: eddie 0.5
by Mike Meyer 10 Sep '11

10 Sep '11

Eddie 0.5 has been uploaded to hackage and it's googlecode repository ( http://eddie.googlecode.com/) Changes include adding a file processing mode to complement the line processing mode, and a list processing mode that works with both of those. Errors are now processed more in line with Unix conventions, with the messages going to standard error and the return code being set to indicate what went wrong. Finally, testing is now done with shelltestrunner so they can be run on Windows. Eddie is a tool for applying haskell filters to text files via the unix command line. While this can be done via ghc, eddie provides the framework for dealing with lines and files and in general fitting into the Unix command line environment. It allows the user to think about the filter they are working on, and not the mechanics of dealing file names, etc. <mike

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[ANNOUNCE] Webrexp-1.1
by Vincent Berthoux 08 Sep '11

08 Sep '11

Hi all, I'm pleased to announce the release of Webrexp 1.1 (first announced version), the web scraping command line utility. This utility is able to extract data from a corpus of HTML, XML & Json files and dump linked files on the hard disk. Here is a tiny RSS/ATOM title reader to help understand the use of this utility : webrexp '"http://someurl.com" >> (item | entry) title [.]' Hackage: http://hackage.haskell.org/package/Webrexp User documentation : https://github.com/Twinside/Webrexp/wiki/Webrexp GitHub: https://github.com/Twinside/Webrexp Regards, Vincent

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[ANNOUNCE] network-address-0.2.0
by Sebastian Nowicki 08 Sep '11

08 Sep '11

Hi All, I'm pleased to announce the release of network-address v0.2.0. The library provides data structures and textual representation of network addresses (IPv4, IPv6, subnets). Major changes in this release: * Revised Address type class (readAddress was moved out of the class, readsAddress :: String -> ReadS a was added for better error reporting) * Better support for IPv6 parsing (compressed zeroes). * Implementation of RFC5952 (a recommendation for IPv6 text representation). Most notably showAddress for IPv6 compresses zeroes. Example GHCi session: *Data.Network.Address> let ip = readAddress "2001:db8:0:0:0::1" :: IPv6 *Data.Network.Address> ip IPv6 2306139568115548160 1 *Data.Network.Address> showAddress ip "2001:db8::1" *Data.Network.Address> let subnet = readSubnet "2001:db8::1/56" :: IPSubnet IPv6 *Data.Network.Address> showSubnet subnet "2001:db8::/56" *Data.Network.Address> ip `member` subnet True Planned for the next release: * Support for parsing IPv4 notation embedded in IPv6 (e.g. "::192.168.1.1") * Performance optimisations - IPv6 parsing/pretty printing is quite slow due to zero compression (>2x speed decrease) The next release will likely be v1.0.0 as there isn't much to add. I'd like to keep the API stable in that version, I welcome any feedback regarding the API (or otherwise). Hackage: http://hackage.haskell.org/package/network-address GitHub: https://github.com/sebnow/haskell-network-address Regards, Sebastian

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Call for Papers - First International Workshop on Bidirectional Transformations
by Janis Voigtländer 08 Sep '11

08 Sep '11

=============================================================== CALL FOR PAPERS First International Workshop on Bidirectional Transformations (BX 2012) Tallinn, Estonia Sun, March 25, 2012 (co-located with ETAPS 2012) http://www.program-transformation.org/BX12 =============================================================== INVITED SPEAKERS: * Juan de Lara (Autonomous University of Madrid, Spain) * second invited speaker still to be decided IMPORTANT DATES: * Paper submission: Mon, December 19, 2011 * Author notification: Tue, January 24, 2012 * Camera-ready papers: Sun, February 5, 2012 To facilitate smooth organization of the review process, authors are asked to submit a short abstract by December 12, 2011. SUBMISSION CATEGORIES: * Regular submissions (max. 15 pages, formal proceedings) * Short papers (max. 8 pages, informal proceedings) * Lightning talks (extended abstract) Submissions can be in LNCS or EC-EASST style. More details can be found on the webpage. PROCEEDINGS: There will be formal proceedings containing all accepted regular papers, published as a volume of EC-EASST (Electronic Communications of the European Association of Software Science and Technology, http://journal.ub.tu-berlin.de/eceasst) Short papers will be included in informal proceedings distributed at the workshop, and their authors may be invited to extend their contribution to a full paper for inclusion in the formal proceedings. SCOPE: Bidirectional transformations (bx) are a mechanism for maintaining the consistency of two (or perhaps more) related sources of information. Such sources can be databases, software models, documents, or their abstract models like graphs or trees. The methodologies used for bx range from classical program transformation to graph transformation techniques, from ad-hoc techniques for data synchronization to the development of domain-specific languages and their integration. We also solicit papers on model/metamodel co-evolution, which is a different yet closely related subject. The aim of the workshop is to bring together researchers, from all relevant areas, interested in bidirectional transformations from different perspectives, such as: language-based approaches, software/model transformations, and data/schema co-evolution. Topics of interest for BX 2012 include, but are not limited to: * (coupled) software/model transformations * software-model synchronization * data-schema co-evolution and data synchronization * consistency analysis * language-based approaches * analysis/classification of requirements for bx technologies * case studies and tool support * comparison of bx technologies * efficiency of algorithms and benchmarks Regular submissions (11-15 pages) can be: * research papers providing new concepts and results * position papers and research perspectives * papers that apply bx in new domains * papers closing gaps between formal concepts and application scenarios For details about short papers and lightning talks, please consult the webpage. PROGRAM CO-CHAIRS: * Frank Hermann (Technical University of Berlin, Germany; University of Luxembourg, Luxembourg) * Janis Voigtländer (University of Bonn, Germany) PROGRAM COMMITTEE MEMBERS: * Paolo Atzeni (Roma Tre University, Italy) * Benjamin Braatz (University of Luxembourg, Luxembourg) * Anthony Cleve (University of Namur, Belgium) * Alcino Cunha (University of Minho, Portugal) * Carlo Curino (Massachusetts Institute of Technology, USA) * Davide Di Ruscio (University of L'Aquila, Italy) * Zinovy Diskin (University of Waterloo, Canada) * Ulrike Golas (Zuse Institute Berlin, Germany) * Ekkart Kindler (Technical University of Denmark, Denmark) * Kazutaka Matsuda (Tohoku University, Japan) * Fernando Orejas (Technical University of Catalonia, Spain) * Benjamin Pierce (University of Pennsylvania, USA) * Andy Schürr (Technical University of Darmstadt, Germany) * Perdita Stevens (University of Edinburgh, UK) * James Terwilliger (Microsoft, USA) * Antonio Vallecillo (University of Málaga, Spain) * Yingfei Xiong (University of Waterloo, Canada) -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

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Haskell Weekly News: Issue 198
by Daniel Santa Cruz 07 Sep '11

07 Sep '11

Welcome to issue 198 the HWN, a newsletter covering developments in the Haskell community. This release covers the week of August 28 to September 3, 2011. Announcements Eric Y. Know released the 5th edition of the Parallel Haskell Digest. [1] http://goo.gl/Jqx01 New and Updated Projects * swapper (New - Roman Smrz) Provides a wrapper for functors, which allows their data to be automatically and transparently swapped to disk and loaded back when necessary. [2] http://goo.gl/CwojE * GA (New - Kenneth Hoste) Provides support for working with genetic algorithms in Haskell. [3] http://goo.gl/XjvFA * hledger[-web] (Update - Simon Michael) Bugfix update. [4] http://goo.gl/98ApM * bindings-DSL (Update - Mauricio CA) Provides a language to describe foreign interfaces on top of hsc2hs. [5] http://goo.gl/fFL4Y * hspec (Update - Trystan Spangler) This latest release includes a command line runner that can search through directory trees for specs and support for nested specs. [6] http://goo.gl/rVbF0 * EclipseFP (Update - JP Moresmau) New features and bugfixes. [7] http://goo.gl/dXS6t Quotes of the Week * dankna: I do [gui on osx] by writing a polyglot ObjC/Haskell program * maurer: I'd do it kmc style * hpc: your next challenge: write a definition of fix in java that fits in a twitter post * kmc: i leave for 3 seconds and you're all metaprogramming and shit * acowley: Haskellers are so abstract they can't even spell primitive * edwardk: i was happy that i had the 4th entry on google for a topic... but then i realized it was only for me, not for everyone that searches for it * kmc: oh, my suggestion was to hand off the fd's directly through a UNIX socket ... but that's probably silly ... i just like the fact that fd's can be passed through a unix socket * monochrom: "linear types change the world!" says Wadler. "Record updates change the type!" says Haskell. :) * gosu: Type parameters are covariant. This is not sound, and that does not matter. * Yitzchak Gale: I certainly wouldn't dream of dragging in type-level olegery, unsafe coercion, implicit parameters and other experimental extensions. Simplicity just works. Top Reddit Stories * 8 ways to report errors in Haskell revisited : Inside 233 Domain: blog.ezyang.com, Score: 51, Comments: 33 On Reddit: [8] http://goo.gl/RBcIL Original: [9] http://goo.gl/A2m2Z * Yesod 0.9 Released! A Massive Changelog explained. Domain: yesodweb.com, Score: 43, Comments: 6 On Reddit: [10] http://goo.gl/go7Zo Original: [11] http://goo.gl/dGoMa * EclipseFP 2.1.0 released, with Hoogle and HLint integration, and much more! Domain: jpmoresmau.blogspot.com, Score: 40, Comments: 42 On Reddit: [12] http://goo.gl/6E1QV Original: [13] http://goo.gl/mkx7g * And they say complexity has no philosophical implications Domain: scottaaronson.com, Score: 36, Comments: 9 On Reddit: [14] http://goo.gl/g97k3 Original: [15] http://goo.gl/9OGU7 * data Maybe -- harmful? Domain: blog.dbpatterson.com, Score: 29, Comments: 26 On Reddit: [16] http://goo.gl/fd2QC Original: [17] http://goo.gl/x4ibO * haskell-TLS framework progress report Domain: tab.snarc.org, Score: 29, Comments: 14 On Reddit: [18] http://goo.gl/Mdc8x Original: [19] http://goo.gl/UpyZ6 * I made a simple image upload site using haskell, sqlite3 and lighttpd. Check it out. Domain: self.haskell, Score: 27, Comments: 15 On Reddit: [20] http://goo.gl/vuF8E Original: [21] http://goo.gl/vuF8E * Manuel Chakravarty on Data Parallel Haskell Domain: vimeo.com, Score: 26, Comments: 2 On Reddit: [22] http://goo.gl/CLXJU Original: [23] http://goo.gl/jCf9w * Functional Programming Day : Oct 14th, Cambridge, UK SPJ & D Syme - early book. bef. Aug 31st Domain: fpday.net, Score: 18, Comments: 11 On Reddit: [24] http://goo.gl/wbIWr Original: [25] http://goo.gl/8OPgK * How does AwesomePrelude transform non-strict code to efficient strict code? Domain: self.haskell, Score: 18, Comments: 12 On Reddit: [26] http://goo.gl/VgIQt Original: [27] http://goo.gl/VgIQt * Composable MVCs (or UIs), a google talk by Conal Elliot Domain: youtube.com, Score: 18, Comments: 14 On Reddit: [28] http://goo.gl/9ekmO Original: [29] http://goo.gl/GDEkN Top StackOverflow Questions * Good examples of Not a Functor/Functor/Applicative/Monad? votes: 17, answers: 3 Read on SO: [30] http://goo.gl/F2q5y * Haskell: What monad did I just reinvent? votes: 17, answers: 4 Read on SO: [31] http://goo.gl/HCko4 * Why is Scalas type inference not as powerful as Haskells? votes: 17, answers: 4 Read on SO: [32] http://goo.gl/gvCF1 * Hard to understand Haskell memory allocation behaviour votes: 11, answers: 1 Read on SO: [33] http://goo.gl/X7HtB * Haskell on JVM? votes: 11, answers: 1 Read on SO: [34] http://goo.gl/Ra4kA * Implementations of spatial indexes in Haskell? votes: 11, answers: 1 Read on SO: [35] http://goo.gl/ThqRA * Does Haskell have variadic functions/tuples? votes: 9, answers: 3 Read on SO: [36] http://goo.gl/NLYCE * couldn't match expected type (Int -> Int -> Int) with actual type `(t0, t1, t2)' votes: 9, answers: 2 Read on SO: [37] http://goo.gl/5EmAS * What is the advantage of using a parser generator like happy as opposed to using parser combinators? votes: 9, answers: 3 Read on SO: [38] http://goo.gl/04s9n * manually defining boolean conjunction votes: 8, answers: 1 Read on SO: [39] http://goo.gl/FGbAj About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstcruz(a)gmail.com. Until next time, Daniel Santa Cruz References 1. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92123 2. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18903 3. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18908 4. http://permalink.gmane.org/gmane.comp.finance.ledger.hledger/479 5. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18909 6. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18912 7. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/92150 8. http://blog.ezyang.com/2011/08/8-ways-to-report-errors-in-haskell-revisited/ 9. http://www.reddit.com/r/haskell/comments/jy34j/8_ways_to_report_errors_in_h… 10. http://www.yesodweb.com/blog/2011/08/announcing-yesod-0.9 11. http://www.reddit.com/r/haskell/comments/jy42c/yesod_09_released_a_massive_… 12. http://jpmoresmau.blogspot.com/2011/09/eclipsefp-210-released.html 13. http://www.reddit.com/r/haskell/comments/k2idm/eclipsefp_210_released_with_… 14. http://www.scottaaronson.com/blog/?p=103 15. http://www.reddit.com/r/haskell/comments/k2kuu/and_they_say_complexity_has_… 16. http://blog.dbpatterson.com/post/9528836599 17. http://www.reddit.com/r/haskell/comments/jxj8i/data_maybe_harmful/ 18. http://tab.snarc.org/post/2011/8/31/tls_progress/ 19. http://www.reddit.com/r/haskell/comments/k12g7/haskelltls_framework_progres… 20. http://www.reddit.com/r/haskell/comments/k2b10/i_made_a_simple_image_upload… 21. http://www.reddit.com/r/haskell/comments/k2b10/i_made_a_simple_image_upload… 22. http://vimeo.com/28477220 23. http://www.reddit.com/r/haskell/comments/k3x2l/manuel_chakravarty_on_data_p… 24. http://www.fpday.net/fpday2011/index.php 25. http://www.reddit.com/r/haskell/comments/jz592/functional_programming_day_o… 26. http://www.reddit.com/r/haskell/comments/k05fo/how_does_awesomeprelude_tran… 27. http://www.reddit.com/r/haskell/comments/k05fo/how_does_awesomeprelude_tran… 28. http://www.youtube.com/watch?v=faJ8N0giqzw 29. http://www.reddit.com/r/haskell/comments/k14k7/composable_mvcs_or_uis_a_goo… 30. http://stackoverflow.com/questions/7220436/good-examples-of-not-a-functor-f… 31. http://stackoverflow.com/questions/7223901/haskell-what-monad-did-i-just-re… 32. http://stackoverflow.com/questions/7234095/why-is-scalas-type-inference-not… 33. http://stackoverflow.com/questions/7247058/hard-to-understand-haskell-memor… 34. http://stackoverflow.com/questions/7261039/haskell-on-jvm 35. http://stackoverflow.com/questions/7270796/implementations-of-spatial-index… 36. http://stackoverflow.com/questions/7220953/does-haskell-have-variadic-funct… 37. http://stackoverflow.com/questions/7232375/couldnt-match-expected-type-int-… 38. http://stackoverflow.com/questions/7269025/what-is-the-advantage-of-using-a… 39. http://stackoverflow.com/questions/7220297/manually-defining-boolean-conjun…

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