August 2009 - Haskell

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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Call For Papers: APLAS 2009 (Korea, Dec 14-16, 2009)
by Zhenjiang Hu 09 Oct '09

09 Oct '09

=============================================================== FIRST CALL FOR PAPERS The Seventh Asian Symposium on Programming Languages and Systems (APLAS 2009) Seoul, December 14-16, 2009 http://ropas.snu.ac.kr/aplas09/ =============================================================== APLAS aims at stimulating programming language research by providing a forum for the presentation of recent results and the exchange of ideas and experience in topics concerned with programming languages and systems. APLAS is based in Asia, but is an international forum that serves the worldwide programming languages community. The APLAS series is sponsored by the Asian Association for Foundation of Software (AAFS), which has recently been founded by Asian researchers in cooperation with many researchers from Europe and the USA. The past formal APLAS symposiums were successfully held in Bangalore (2008, India), Singapore (2007), Sydney (2006, Australia), Tsukuba (2005, Japan), Taipei (2004, Taiwan) and Beijing (2003, China) after three informal workshops held in Shanghai (2002, China), Daejeon (2001, Korea) and Singapore (2000). Proceedings of the past symposiums were published in Springer-Verlag's LNCS 2895, 3302, 3780, 4279, and 5356. TOPICS: The symposium is devoted to both foundational and practical issues in programming languages and systems. Papers are solicited on, but not limited, to the following topics: * semantics, logics, foundational theory * type systems, language design * program analysis, optimization, transformation * software security, safety, verification * compiler systems, interpreters, abstract machines * domain-specific languages and systems * programming tools and environments INVITED SPEAKERS: TBA IMPORTANT DATES: Abstract Deadline: June 8 (Monday), 2009 Paper Submission Deadline: 24:00 AM (in Samoan Time), June 15 (Monday), 2009 Author Notification: August 17, 2009 Camera Ready: September 14, 2009 Conference: December 14-16, 2009 SUBMISSIONS INFORMATION: Papers should be submitted electronically online via the conference submission web page at URL <http://www.easychair.org/conferences/?conf=aplas2009>. Acceptable formats are PostScript or PDF, viewable by Ghostview or Adobe Reader. Submissions should not exceed 16 pages in LNCS format, including bibliography and figures. Submitted papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. They should clearly identify what has been accomplished and why it is significant. Submitted papers must be unpublished and not submitted for publication elsewhere. The proceedings of the symposium is planned to be published as a volume in Springer-Verlag's Lecture Notes in Computer Science series. Authors of selected papers will be invited after the symposium to submit a full version for publication in a special issue of New Generation Computing. GENERAL CHAIR Kwangkeun Yi (Seoul National University, Korea) PROGRAM CHAIR Zhenjiang Hu (National Institute of Inforamtics, Japan) PROGRAM COMMITTEE Manuel M. T. Chakravarty (University of New South Wales, Australia) Wei-Ngan Chin (National University of Singapore, Singapore) Nate Foster (University of Pennsylvania, USA) Ralf Hinze (Oxford University, United Kingdom) Zhenjiang Hu (National Institute of Informatics, Japan), Chair Ik-Soon Kim (Electronics and Telecommunications Research Institute, Korea) Julia Lawall (DIKU, Denmark) Sebastian Maneth (NICTA and University of New South Wales, Australia) Sungwoo Park (Pohang University of Science and Technology, Korea) G. Ramalingam (Microsoft Research, India) Peter Thiemann (University of Freiburg, Germany) Kazushige Terui (Kyoto University, Japan) Janis Voigtländer (Technical University of Dresden, Germany) Chung-chieh Shan (Rutgers University, USA) Kazunori Ueda (Waseda University, Japan) Bow-Yaw Wang (Academia Sinica, Taiwan) Jianjun Zhao (Shanghai Jiaotong University, China) POSTER CHAIR Kiminori Matsuzaki (University of Tokyo, Japan)

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ANNOUNCE: jhc 0.7.1
by John Meacham 27 Aug '09

27 Aug '09

Hi, I am happy to announce the jhc optimizing haskell compiler version 0.7.1. Information on installing jhc is here: http://repetae.net/computer/jhc/building.shtml And the Main page is here: http://repetae.net/computer/jhc There have been a lot of changes since the last public release, Some notable ones are: * The use of a general compiler cache by default rather than object files. This means work done by jhc is shared between projects, jhc uses cryptographic hashes internally to never compile the same piece of code more than once. This has numerous benefits, a notable one being speed. * Reworked library support. Jhc libraries are now much more general, when linking only the bits needed are loaded from the hl file, libraries are allowed to re-export modules from other libraries, making versioning or providing multiple interfaces to the same functionality a lot simpler. Library conflicts are 'lazy', like ambiguity errors now. * Updated Manual, clearer build instructions * Support for writing pure C libraries in Haskell. * numerous library updates, filled out many IO routines that were stubs before * Smart progress meters when compiler for a better user experience * performs all typechecking before compilation, for a faster edit-compile loop when writing code with jhc. * various bug fixes * Cross Compilation improvements, for instance you can compile for windows transparently on a linux box. Or for an embedded target that is independent of the host. * Better Mac OSX Support, as both a host and target. If you are wondering about the large version number bump since the last release, It is because several versions were released only internally to the jhc list for testing. If you are interested in jhc, join the list at: http://www.haskell.org/mailman/listinfo/jhc John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/

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SLE 2009 Denver Colorado - Call for participation
by Serebrenik, A. 27 Aug '09

27 Aug '09

___________________________________________________________ Call for Participation - SLE 2009 2nd International Conference on Software Language Engineering http://planet-sl.org/sle2009 Denver, Colorado, October 5-6, 2009 ____________________________________________________________ Co-located with 12th International Conference on Model-Driven Engineering Languages and Systems (MODELS 2009) and 8th International Conference on Generative Programming and Component Engineering (GPCE 2009) Highlights: - Research Program: 15 research papers, 6 short papers and 2 tool demos (program listed below) - Keynote Speakers: Jean Bezivin and James Cordy - Early Registration: Open until Sept 14, 2008 Conference ---------- The 2nd International Conference on Software Language Engineering (SLE) is devoted to topics related to artificial languages in software engineering. SLE's foremost mission is to encourage and organize communication between communities that have traditionally looked at software languages from different, more specialized, and yet complementary perspectives. SLE emphasizes the fundamental notion of languages as opposed to any realization in specific "technical spaces". SLE 2009 will be co-located with the 12th IEEE/ACM International Conference on Model-Driven Engineering Languages and Systems (MODELS 2009) and 8th International Conference on Generative Programming and Component Engineering (GPCE 2009). Scope ----- The term 'software language' comprises all sorts of artificial languages used in software development, including general-purpose programming languages, domain-specific languages, modeling and meta-modeling languages, data models, and ontologies. Used in its broadest sense, examples include modeling languages such as UML-based and domain-specific modeling languages, business process modeling languages, and web application modeling languages. The term 'software language' also comprises APIs and collections of design patterns that are implicitly defined languages. Software language engineering is the application of a systematic, disciplined, quantifiable approach to the development, use, and maintenance of these languages. Thus, the SLE conference is concerned with all phases of the life cycle of software languages; these include the design, implementation, documentation, testing, deployment, evolution, recovery, and retirement of languages. Of special interest are tools, techniques, methods and formalisms that support these activities. In particular, tools are often based on or even automatically generated from a formal description of the language. Hence, of special interest is the treatment of language descriptions as software artifacts, akin to programs - while paying attention to the special status of language descriptions, subject to tailored engineering principles and methods for modularization, refactoring, refinement, composition, versioning, co-evolution, and analysis. Accepted Papers --------------- Research Papers * August Schwerdfeger and Eric Van Wyk. Verifiable Parse Table Composition for Deterministic Parsing * Frédéric Mallet, Francois Lagarde, Charles André, Sebastien Gerard and Francois Terrier. An Automated Process for implementing Multi-level domain models * Krzysztof Czarnecki, Thiago Tonelli Bartolomei, Ralf Laemmel and Tijs van der Storm. Transcript of an API migration for two XML APIs * Lukas Renggli, Marcus Denker and Oscar Nierstrasz. Language Boxes: Bending the Host Language with Modular Language Changes * Maartje de Jonge, Emma Nilsson-Nyman, Lennart C. L. Kats and Eelco Visser. Natural and Flexible Error Recovery for Generated Parsers * Markus Herrmannsdoerfer, Daniel Ratiu and Guido Wachsmuth. Language Evolution in Practice: The History of GMF * Mathieu Acher, Philippe Collet, Philippe Lahire and Robert France. Composing Feature Models * Mauricio Alferez, João Santos, Ana Moreira, Alessandro Garcia, Uirá Kulesza, João Araújo and Vasco Amaral. Multi-View Composition Language for Software Product Line Requirements * Nils Thieme, Christian Wende and Steffen Zschaler. A Role-based Approach Towards Modular Language Engineering * Steffen Zschaler, Dimitrios Kolovos, Nicholas Drivalos, Richard Paige and Awais Rashid. Domain-Specific Metamodelling Languages for Software Language Engineering * Steffen Zschaler, Pablo Sanchez, Joao Santos, Mauricio Alferez, Awais Rashid, Lidia Fuentes, Ana Moreira, Joao Araujo and Uira Kulesza. VML* -- A Family of Languages for Variability Management in Software Product Lines * Tihamer Levendovszky, Anantha Narayanan, Daniel Balasubramanian and Gabor Karsai. A Novel Approach to Semi-Automated Evolution of DSML Model Transformation * Tim Bauer and Martin Erwig. Declarative Scripting in Haskell * Uwe Jugel. Generating Smart Wrapper Libraries for Arbitrary APIs * Zef Hemel and Eelco Visser. PIL: A Platform Independent Language for Retargetable DSLs Short papers * Anya Helene Bagge. Yet Another Language Extension Scheme * Daniel Spiewak and Tian Zhao. ScalaQL: Language-Integrated Database Queries for Scala * Danny M. Groenewegen and Eelco Visser. Integration of Data Validation and User Interface Concerns in a DSL for Web Applications * Ivan Kurtev and Alfons Laarman. Ontological Metamodeling with Explicit Instantiation * Jerónimo Irazábal and Claudia Pons. Model transformation languages relying on models as ADTs * Paul Laird and Stephen Barrett. Towards the Dynamic Evolution of Domain Specific Languages Tools * Elina Kalnina, Audris Kalnins, Edgars Celms and Agris Sostaks. Graphical template language for transformation synthesis * Florian Heidenreich, Jendrik Johannes, Mirko Seifert and Christian Wende. Closing the Gap between Modelling and Java Registration ------------ Registration is open now. Early bird registration is open until Sept 14. Regitration is available at: https://register.cce.umn.edu/Course.pl?sect_key=183427 Keynote Speakers ---------------- * James Cordy, Queens University, Canada * Jean Bezivin, INRIA & Ecole des Mines de Nantes, France Organization ------------ Steering Committee * Mark van den Brand, TU Eindhoven, The Netherlands * James Cordy, Queen's University, Canada * Jean-Marie Favre, University of Grenoble, France * Dragan Gasevic, Athabasca University, Canada * Gorel Hedin, Lund University, Sweden * Ralf Laemmel, Universitat Koblenz-Landau, Germany * Eric Van Wyk, University of Minnesota, USA * Andreas Winter, Johannes Gutenberg-Universitat Mainz, Germany General Chair * Dragan Gasevic, Athabasca University, Canada Program Committee Co-Chairs * Mark van den Brand, TU Eindhoven, The Netherlands * Jeff Gray, University of Alabama at Birmingham, USA Program Committee * Colin Atkinson, Universität Mannheim, Germany * Don Batory, University of Texas at Austin, USA * Paulo Borba, Universidade Federal de Pernambuco, Brazil * John Boyland, University of Wisconsin, Milwaukee, USA * Marco Brambilla, Politecnico di Milano, Italy * Shigeru Chiba, Tokyo Institute of Technology, Japan * Charles Consel, LaBRI / INRIA, France * Gregor Engels, Universität Paderborn, Germany * Stephen A. Edwards, Columbia University, USA * Robert Fuhrer, IBM T.J. Watson Research, USA * Martin Gogolla, University of Bremen, Germany * Giancarlo Guizzardi, Federal University of Espírito Santo, Brazil * Reiko Heckel, University of Leicester, UK * Frédéric Jouault, INRIA & Ecole des Mines de Nantes, France * Nicholas Kraft, University of Alabama, USA * Thomas Kühne, Victoria University of Wellington, New Zealand * Julia Lawall, University of Copenhagen, Denmark * Timothy Lethbridge, University Ottawa, Canada * Brian Malloy, Clemson University, USA * Kim Mens, Université catholique de Louvain, Belgium * Marjan Mernik, University of Maribor, Slovenia * Todd Millstein, University of California, Los Angeles, USA * Pierre-Etienne Moreau, INRIA Nancy - Grand Est, France * Pierre-Alain Muller, University of Haute-Alsace, France * Daniel Oberle, SAP Research, Germany * Richard Paige, University of York, UK * James Power, National University of Ireland, Ireland * João Saraiva, Universidade do Minho, Portugal * Mary Lou Soffa, University of Virginia, USA * Juha-Pekka Tolvanen, MetaCase, Finland * Alexander Serebrenik, Eindhoven University of Technology, Netherlands * Tony Sloane, Macquarie University, Australia * Steffen Staab, Universität Koblenz-Landau, Germany * Jun Suzuki, University of Massachusetts, Boston, USA * Walid Taha, Rice University, USA * Eli Tilevich, Virginia Tech, USA * Jurgen Vinju, CWI, Netherlands * Eelco Visser, Delft University of Technology, Netherlands * René Witte, Concordia University, Canada Organization Committee * Bardia Mohabbati, Simon Fraser University, Canada (Web Chair) * James Hill, Vanderbilt University, USA (Publicity co-Chair) * Alexander Serebrenik, TU Eindhoven, The Netherlands (Publicity co-Chair) * Eric Van Wyk, University of Minnesota (Finance Chair)

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Haskell Weekly News: Issue 128 - August 26, 2009
by Brent Yorgey 26 Aug '09

26 Aug '09

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20090826 Issue 128 - August 26, 2009 --------------------------------------------------------------------------- Welcome to issue 128 of HWN, a newsletter covering developments in the [1]Haskell community. New releases of haddock, gitit, jhc, formlets, and lots of other libraries and tools; Edinburgh Hack Day, ICFP, and HacPDX coming up; exciting times! The Google Summer of Code has also wrapped up. See below for final progress reports from this summer's Haskell participants. PS: Just as this was going to press, Thomas Ten Cate released the Scion library from his Google Summer of Code project; hence it isn't listed below but you should check it out anyway! Announcements GLUT 2.2.1.0. Sven Panne [2]announced a new version of the [3]GLUT package. The package is now autoconf-free, with API entries are resolved dynamically at runtime; support for sRGB framebuffers has been added; and support for context profiles has been added. Potential Network SIG. Thomas DuBuisson [4]announced the formation of a SIG to hammer out a design for a new Network API, seeing as the current API, a straight-forward Berkeley binding, doesn't seem to please anyone in a Haskell context. epoll bindings 0.1.1. Toralf Wittner [5]announced the release of [6]epoll bindings 0.1.1. Epoll is an I/O event notification facility for Linux similar to poll but with good scaling characteristics. Currently the bindings are fairly low level and close to the C API, but there are plans to add some buffer or stream abstraction on top. Eventually, when GHC can make use of epoll/kqueue in addition to select, this library will not be needed anymore. Until then it might be useful for applications which monitor large numbers of file descriptors. gitit 0.6.1. John MacFarlane [7]announced the release of [8]gitit 0.6.1, a wiki program that runs on happstack, the Haskell web application server stack, and stores pages and other content in a git or darcs filestore. The whole code base has been overhauled since the last release: gitit is now faster, more memory efficient, more modular, and more secure. It also has many new features, including page metadata and categories, atom feeds (sitewide and per-page), support for literate Haskell, a better configuration system, an improved caching system, a Haskell library exporting happstack wiki handlers, and a plugin system. jhc 0.7.1. John Meacham [9]announced the 0.7.1 release of the [10]jhc optimizing Haskell compiler. There have been a lot of changes since the last public release. Some notable ones include the use of a general compiler cache by default rather than object files; reworked library support; an updated manual, with clearer build instructions; support for writing pure C libraries in Haskell; numerous library updates; smart progress meters; typechecking before compilation; and various bug fixes and cross compilation improvements. rss2irc 0.3 released. Simon Michael [11]announced the release of [12]rss2irc version 0.3, an irc bot created by Don Stewart to watch rss feeds and announce new items on irc, now maintained by Simon. This version includes reliable http networking, irc flood protection, better error handling & reporting, extensive debugging output, Atom support, more useful defaults, precise control of irc output, and is now installable on OSX. Feedback and patches welcome. formlets 0.6. Chris Eidhof [13]announced that the formlets team has released a new version of [14]formlets, a library to build type-safe, composable web forms. Most notably, Mightybyte and Chris worked on the [15]massInput functionality, which is now ready for use! graphtype -- A simple tool to illustrate dependencies between Haskell types. Max Desyatov [16]announced the release of [17]graphtype, a tool for visualising type declarations in Haskell source files. It produces [18].dot-files for subsequent processing with graphviz. OAuth library in haskell. Diego Souza [19]announced the release of [20]hoauth, a library which helps you to deal with the [21]oauth protocol. Currently it supports only consumer side applications, but there are plans to add service providers support in near future. ByteString Nums. Jason Dusek [22]announced [23]bytestring-nums, a simple package for relatively careless parsing of numbers from ByteStrings. It works to parse out integer strings, floating point strings and hex strings. haskell-src-exts-1.1.3. Niklas Broberg [24]announced the release of [25]haskell-src-exts-1.1.3, a package for Haskell source code manipulation. It handles (almost) all syntactic extensions to the Haskell 98 standard implemented by GHC, and the parsing can be parametrised on what extensions to recognise. haskell-src-exts-1.1.3 is a highly experimental release, which does not change the current stable part of haskell-src-exts. But it includes a whole new set of modules implementing a new and more accurate syntax tree where all nodes are adorned with annotations. Together with this comes a parser that retains exact source information, stored in the aforementioned annotations. Help in testing and bug reporting is welcome and appreciated! ministg-0.2, an interpreter for STG operational semantics. Bernie Pope [26]announced the first public release of [27]Ministg, an interpreter for a high-level, small-step, operational semantics for the STG machine, the abstract machine at the core of GHC. One of the main features of Ministg is the ability to record a trace of the execution steps as a sequence of HTML files; here is an [28]example trace. OpenCLRaw 1.0.1000. Jeff Heard [29]announced the release of [30]OpenCLRaw, a raw binding to the OpenCL, a platform for single-host heterogeneous, data-parallel computing. He has future plans to create higher-level bindings on top of these raw ones. compose-trans-0.0. Miguel Mitrofanov [31]announced [32]compose-trans, a small library intended to make monad transformers composable. Haddock version 2.5.0. David Waern [33]announced the release of [34]Haddock 2.5.0. This version reverts to the old multi-page index for large packages, shows GADT records in the generated documentation, adds a --use-unicode flag for displaying prettier versions of common symbols, and many other changes. Edinburgh Meetup (Sat 29 Aug) and Hack Day (Sun 30 Aug). Eric Kow [35]sent a reminder that we will be having a [36]Hack Day in Edinburgh on Sunday 30 August at the ICFP venue. There will also be a meetup the day before, 09:30 Saturday 29 August just outside the ICFP venue; we'll have a quick wander and hopefully find some nice places to sit and chat, whip out the occasional laptop and fling a lambda or not being careful not to injure the passers-by. Cleaner networking API - network-fancy. Taru Karttunen [37]announced [38]network-fancy, which offers a cleaner API to networking facilities in Haskell. It supports high-level operations on tcp, udp and unix sockets. Feedback on the API is welcome! GLFW-0.4.1. Paul L [39]announced a new version of [40]GLFW, 0.4.1. Notable changes include a workaround for a FFI bug that affects GHC < 6.10 on 64-bit machines, a fix for the compilation problem on OS X for GHC > 6.10.1, a compatibility fix to work with both OpenGL 2.3.0.0 and older versions, choice of a "dynamic" flag to link with dynamic GLFW C library instead, and a number of other fixes, cleanups and improvements. HacPDX, A Hackathon in Portland. Thomas DuBuisson [41]announced [42]HacPDX, an opportunity for Portland Haskell hackers to join together in building and improving libraries and tools. If you've never been, hackathons are typically not only a good opportunity for experienced devs to work together but also a great way for newcomers to get involved in the community. HacPDX will take place Friday September 25 to Sunday September 27 at Portland State University; see the email for more specific details. Hack on the Delve core, with Delve and Haskell. spoon [43]announced [44]Delve, a new programming language intended to bring the benefits of static type checking and functional programming to object-oriented design and development, currently being implemented in Haskell. Contributors welcome! cabal-query 0.1. Max Desyatov [45]announced the release of [46]cabal-query, a package to assist in finding a set of Cabal packages which satisfy your needs. EnumMap-0.0.1. John Van Enk [47]announced the first version of [48]EnumMap, a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. Google Summer of Code Progress updates from participants in the 2008 [49]Google Summer of Code. Haddock improvements! Isaac Dupree has [50]wrapped up his project, with patches waiting to be merged back into both Haddock and GHC. His final post contains a detailed description of the work he did; looks like we'll have much better cross-package documentation support in Haddock soon! EclipseFP. Thomas Ten Cate began adding a notion of [51]build targets to EclipseFP, so that projects can be created without .cabal files. He has [52]wrapped up the project for now, and although he isn't fully happy with the results that he achieved, he was able to make useful contributions which hopefully others can continue to build on. Improving the Haskell space profiling experience. Gergely Patai's project is done: he [53]uploaded hp2any, a set of realtime space profiling tools, to Hackage. He also [54]created a [55]haskellwiki page describing it and its use. haskell-src-exts -> haskell-src. Niklas Broberg has been [56]working on a complete revamp of the AST, lexer and parser to allow for exact source info to be kept in the tree, which in turn will allow exact printing of the code as it was read. darcs. Petr Rockai posted a [57]final report where he described his accomplishments: the hashed-storage library for reading and writing filesystem trees in hash-based formats; darcs whatsnew integration with hashed-storage; progress on a new and improved version of hashed-storage, and a branch of darcs depending on it; and darcs-benchmark, a standalone package for benchmarking darcs. Discussion Unification and matching in Abelian groups. John D. Ramsdell [58]shared some code implementing unification and matching in Abelian groups. Grouping and SIMD in parallel Haskell (using Nested Data Parallel Haskell ideas in legacy code). Zefirov Sergey [59]posted some code showing how to translate Parallel Haskell programs (expressed with par and pseq) into Nested Data Parallel Haskell. Request for Comments - hscurrency 0.0.1. Max Cantor [60]requested feedback on some simple tools to do safe calculations on different currencies. DDC compiler and effects; better than Haskell? (was Re: unsafeDestructiveAssign?). Peter Verswyvelen began a long [61]discussion about the DDC compiler and its effect system, and the relationship to Haskell and monads. Jobs Credit Suisse is hiring. Ganesh Sittampalam [62]announced that the Global Modelling and Analytics Group (GMAG) at Credit Suisse is once again looking to hire functional programmers; see his email for more information. Jane Street is Hiring (as if you didn't already know). Yaron Minsky sent out a [63]reminder that [64]Jane Street is looking to hire functional programmers; see his email for more details. He also mentioned that he will be at parts of ICFP, CUFP and DEFUN this year, so if you're interested, come and talk to him there. Galois is Hiring. Don Stewart [65]announced that Galois is continuing to hire, with multiple positions for talented functional programmers (with both junior and senior positions). They will be at ICFP and related events; see Don or Lee Pike. Blog noise [66]Haskell news from the [67]blogosphere. Blog posts from people new to the Haskell community are marked with >>>, be sure to welcome them! * Isaac Dupree: [68]Summer of Code Wrap-Up.. * Thomas ten Cate: [69]Endgame. * Jeff Heard: [70]Followup to my earlier post on Hilbert curve timeseries plots. * Jeff Heard: [71]Plotting timeseries in space filling curves. * Magnus Therning: [72]Making a choice from a list in Haskell, Vty (part 5, the last one). * Magnus Therning: [73]Fork/exec in Haskell. * Edward Kmett: [74]Iteratees, Parsec and Monoids (Slides). * Chris Smith: [75]Flow Equivalence Code in Haskell. * Thomas Ten Cate: [76]Build targets. * Chris Smith: [77]Catching a Mathematical Error Using Haskell's Type System. * Well-Typed: [78]Industrial Haskell Group meeting at CUFP. * London HUG: [79]Next meeting: Alex McLean, Live coding music with Haskell. * David Amos: [80]Finite fields, part 1. * Greg Bacon: [81]Simple analogy for lazy evaluation . * Magnus Therning: [82]JSON in Haskell. * Notes on the LHC: [83]Status update: New Integer implementation.. * Edward Kmett: [84]Clearer Reflections. * Petr Rockai: [85]soc final report. * Gergely Patai: [86]hp2any overview online. * Brent Yorgey: [87]New 2D text layout library. * Manuel Chakravarty: [88]World's first formal machine-checked proof of a general-purpose operating system kernel.. * Bryan O'Sullivan: [89]Haskell Platform support for Fedora: we're almost there. * Gergely Patai: [90]hp2any on Hackage. * Doug Beardsley: [91]Dynamic List Formlets in Haskell . * Niklas Broberg: [92]Quick update. * Christopher Lane Hinson: [93]FactoryArrow. * Michael Feathers: [94]Imposing the Edges Later . * Brent Yorgey: [95]Species operations: differentiation. * >>> Ron Leisti: [96]A prime number sieve in Haskell. Quotes of the Week * bos: You don't get accurate answers from Perl. It just lies to you to keep you happy. * ray: haskell' will come out in 2020 and be h98 with hierarchical modules * ray: enlarge your kleisli arrow, please the category ladies * quicksilver: making the compiler writer's job painful is one of the main duties of a language designer. * gwern: as a plugin, yes, but that's like being so out of shape that a guy in a wheelchair can outrace you - yes, he needs a tool, but you should still be ashamed of yourself * Cale's Lemma: Any sufficiently long string of operator symbols looks like a fish. * randomwords: How "complete" does an application before it's OK to upload to hackage? <ray> there are no standards <randomwords> lawless wasteland. Got it. * ndm: I was browsing through the Yhc standard libraries, as one does on the weekend, and was drawn to Yhc's sort function. * michaelfeathers: I did a parody post to Haskell Cafe last year where I had some code that was calling (nub . nub) zip12 and asked if there was a zip13 and no one called it out as a joke. About the Haskell Weekly News New editions are posted to [97]the Haskell mailing list as well as to [98]the Haskell Sequence and [99]Planet Haskell. [100]RSS is also available, and headlines appear on [101]haskell.org. To help create new editions of this newsletter, please see the information on [102]how to contribute. Send stories to byorgey at cis dot upenn dot edu. The darcs repository is available at darcs get [103]http://code.haskell.org/~byorgey/code/hwn/ . References 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.general/17442 3. http://hackage.haskell.org/package/GLUT 4. http://article.gmane.org/gmane.comp.lang.haskell.libraries/11813 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62782 6. http://hackage.haskell.org/package/epoll 7. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62776 8. http://gitit.johnmacfarlane.net/ 9. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62759 10. http://repetae.net/computer/jhc 11. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62743 12. http://hackage.haskell.org/package/rss2irc 13. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62738 14. http://hackage.haskell.org/package/formlets 15. http://softwaresimply.blogspot.com/2009/08/dynamic-list-formlets-in-haskell… 16. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62736 17. http://hackage.haskell.org/package/graphtype 18. http://i.piccy.info/i4/00/90/bfa07290012c2d3b455696bdaa86.png 19. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62735 20. http://hackage.haskell.org/package/hoauth 21. http://oauth.net/ 22. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62695 23. http://hackage.haskell.org/package/bytestring-nums 24. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62682 25. http://hackage.haskell.org/package/haskell-src-exts 26. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62559 27. http://www.haskell.org/haskellwiki/Ministg 28. http://www.cs.mu.oz.au/~bjpop/trace/step0.html 29. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62414 30. http://hackage.haskell.org/package/OpenCLRaw 31. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62390 32. http://hackage.haskell.org/package/compose%2Dtrans 33. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62341 34. http://www.haskell.org/haddock 35. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62324 36. http://www.haskell.org/haskellwiki/Hac7 37. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62277 38. http://hackage.haskell.org/package/network%2Dfancy 39. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62259 40. http://hackage.haskell.org/package/GLFW 41. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62195 42. http://haskell.org/haskellwiki/HacPDX 43. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62173 44. http://killersmurf.blogspot.com/ 45. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62139 46. http://hackage.haskell.org/package/cabal%2Dquery 47. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62119 48. http://hackage.haskell.org/package/EnumMap 49. http://hackage.haskell.org/trac/summer-of-code/wiki/SoC2008 50. http://haddock2009.wordpress.com/2009/08/26/summer-of-code-wrap-up/ 51. http://eclipsefp.wordpress.com/2009/08/20/build-targets/ 52. http://eclipsefp.wordpress.com/2009/08/25/endgame/ 53. http://just-bottom.blogspot.com/2009/08/hp2any-on-hackage.html 54. http://just-bottom.blogspot.com/2009/08/hp2any-overview-online.html 55. http://www.haskell.org/haskellwiki/Hp2any 56. http://nibrofun.blogspot.com/2009/08/just-quick-note-since-i-realise-i.html 57. http://web.mornfall.net/blog/soc_final_report.html 58. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/62486 59. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/62403 60. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/62342 61. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/62205 62. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62406 63. http://article.gmane.org/gmane.comp.lang.haskell.general/17436 64. http://www.janestreet.com/ 65. http://article.gmane.org/gmane.comp.lang.haskell.cafe/62191 66. http://planet.haskell.org/ 67. http://haskell.org/haskellwiki/Blog_articles 68. http://haddock2009.wordpress.com/2009/08/26/summer-of-code-wrap-up/ 69. http://eclipsefp.wordpress.com/ 70. http://vis.renci.org/jeff/2009/08/24/followup-to-my-earlier-post-on-hilbert… 71. http://vis.renci.org/jeff/2009/08/24/plotting-timeseries-in-space-filling-c… 72. http://therning.org/magnus/archives/732 73. http://therning.org/magnus/archives/727 74. http://comonad.com/reader/2009/iteratees-parsec-and-monoid/ 75. http://cdsmith.wordpress.com/2009/08/20/flow-equivalence-code-in-haskell/ 76. http://eclipsefp.wordpress.com/2009/08/20/build-targets/ 77. http://cdsmith.wordpress.com/2009/08/19/catching-a-mathematical-error-using… 78. http://blog.well-typed.com/2009/08/industrial-haskell-group-meeting-at-cufp/ 79. http://www.londonhug.net/2009/08/18/next-meeting-alex-mclean-live-coding-mu… 80. http://haskellformaths.blogspot.com/2009/08/finite-fields-part-1.html 81. http://gbacon.blogspot.com/2009/08/simple-analogy-for-lazy-evaluation.html 82. http://therning.org/magnus/archives/719 83. http://lhc-compiler.blogspot.com/2009/08/status-update-new-integer.html 84. http://comonad.com/reader/2009/clearer-reflection/ 85. http://web.mornfall.net/blog/soc_final_report.html 86. http://just-bottom.blogspot.com/2009/08/hp2any-overview-online.html 87. http://byorgey.wordpress.com/2009/08/14/new-2d-text-layout-library/ 88. http://justtesting.org/post/162408446/worlds-first-formal-machine-checked-p… 89. http://www.serpentine.com/blog/2009/08/12/haskell-platform-support-for-fedo… 90. http://just-bottom.blogspot.com/2009/08/hp2any-on-hackage.html 91. http://softwaresimply.blogspot.com/2009/08/dynamic-list-formlets-in-haskell… 92. http://nibrofun.blogspot.com/2009/08/just-quick-note-since-i-realise-i.html 93. http://blog.downstairspeople.org/2009/08/09/factoryarrow/ 94. http://blog.objectmentor.com/articles/2009/08/08/imposing-the-edges-later 95. http://byorgey.wordpress.com/2009/08/05/species-operations-differentiation/ 96. http://www.ronleisti.com/wp/2009/07/26/a-prime-number-sieve-in-haskell/ 97. http://www.haskell.org/mailman/listinfo/haskell 98. http://sequence.complete.org/ 99. http://planet.haskell.org/ 100. http://sequence.complete.org/node/feed 101. http://haskell.org/ 102. http://haskell.org/haskellwiki/HWN 103. http://code.haskell.org/~byorgey/code/hwn/

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Re: [Haskell] ANNOUNCE: jhc 0.7.1
by John Meacham 26 Aug '09

26 Aug '09

On Tue, Aug 25, 2009 at 02:15:14PM +0100, Duncan Coutts wrote: > 1. Would it be possible to have a machine-readable form of: > jhc --list-libraries > > It's possible to parse the output of course but the worry is always that > the format will change again. Good Idea, I'll modify the output to be a proper YAML file with a few guarenteed fields, that will leave room for expansion later and backwards compatability. > 2. In older jhc versions it was possible to specify .hl libraries by > name and version, eg jhc -p filepath-1.0.1.1. In the latest release it > is only possible by name. Is this intentional? I know jhc uses hashes to > uniquely identify installed packages, perhaps it should be possible to > specify packages by hash for the case that one has several instances of > the same package (possibly different versions, or built against > different versions of various dependencies). Ah, this is an unintentional regression. I intended to keep the behavior of being able to specify a library name/version or file name. Being able to specify a hash is also a good idea. > like when there are several packages of the same version but with a > different hash? Maybe a machine readable --list-libraries should list > the hash too. > > > 4. Is there a way to get back the library/package description that jhc > bakes into the .hl files? There's a --show-ho. Perhaps we want a > --show-hl that dumps the library description? I guess that should also > tell us the package hash. --show-ho will also work on hl files, which probably isn't mentioned anywhere in the manual. I think I will add a verbose mode to --list-libraries that will also spit out much of this meta-info (in the aforementioned YAML format) > 5. The ./configure doesn't check for the Haskell readline package. Yeah, I am currently only checking for the purpose of ghc 6.8/6.10 compatibility, but adding checks for all dependencies is a good idea. As an aside, here are the principles that guided the design of the new library system and ho cache. The main motivations were ameliorating two notable shortcomings of jhc, its speed and compatibility with other compilers: * Ho files will only affect speed of compilation, never results. No matter what. This allows the shared ho cache and decoupling the unit of caching from module granularity. * Only the interface of libraries explicitly mentioned on the command line shall affect code compiled by jhc. For instance, a libraries implementation can use an alternate prelude without hurting its compatibility with haskell 98 code. * From the users perspective, a library defines an interface, which is not necessarily coupled to the implementation. I have thought long and hard on the problem of being able to maintain some level of compatibility with ghc and hackage without sacrificing jhc's ability to innovate, or tying its development to the ghc libraries. Making libraries logical 'interfaces' rather than 'implementations' decouples compatibility issues from the compiler itself, anyone can write a library that emulates a particular interface. For instance, a compat-ghc-base3 library might have things like 'Reexport: Compat.Haskell98.Prelude as Prelude, Compat.Ghc.Base3.Monad as Control.Monad, ... '. Or more interestingly, you might create your own library that does a 'Reexport: MyApplicativePrelude as Prelude' to get your own prelude. (this is not fully realized yet in 0.7.1, but will be in a point release soon. The mechanism and framework is there though.) * Stateless. There is no such thing as hidden libraries, libraries mentioned on the command line are available, libraries not mentioned are not. Since libraries can re-export modules this won't cause a command line explosion. For instance, a -phaskell-platform could pull in and make available all the libraries in the haskell platform. * Adding libraries, even incompatible ones, won't break working builds unless said libraries are explicitly mentioned by the build in a non-precise way. This is necessary so a theoretical 'jhc-pkg' tool need only worry about adding required libraries, not cleaning up or worrying about finding consistent sets of libraries. A simple recursive download on dependencies suffices as a rudimentary cabal-install style tool. John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/

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ANN: rss2irc 0.3 released
by Simon Michael 24 Aug '09

24 Aug '09

rss2irc is an irc bot created by Don Stewart to watch rss feeds and announce new items on irc. I have been tweaking and testing it for a while, and have taken up the maintainer reins. I'm happy to announce release 0.3, with: - reliable http networking - irc flood protection - better error handling & reporting - extensive debugging output - Atom support - more useful defaults (enter channel silently, hide email addresses etc.) - precise control of irc output, including regexp rewrites - installable on mac osx Feedback and patches welcome. I am currently using it to run a number of announce-bots on freenode, including hackagebot and darcscommitbot. (A tip: if you experiment, avoid joining the irc server too frequently; once per minute may be ok.) home: http://hackage.haskell.org/package/rss2irc darcs repo: http://joyful.com/darcsweb/darcsweb.cgi?r=rss2irc -Simon

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ANNOUNCE: graphtype — A simple tool to illustrate dependencies between Haskell types
by Max Desyatov 24 Aug '09

24 Aug '09

While developing applications which deal with complex data it is crucial to know how exactly you manipulate this data. Haskell provides excellent tools for expressing a data scheme you work with: ADTs, `type` and `newtype` declarations, type classes and much more is hidden in rich Haskell's type system. Obviously, when types of data in your domain you work with grow — all declarations grow, and it becomes hard to grasp all dependencies, to change them and to remove them deliberately. graphtype was developed to visualise type declarations in you Haskell source files. It produces .dot-file for subsequent processing with graphviz. Results for example file bundled with graphtype: http://i.piccy.info/i4/00/90/bfa07290012c2d3b455696bdaa86.png To play with it, you can use hackage: http://hackage.haskell.org/package/graphtype or hack some code: http://github.com/explicitcall/graphtype Visualisation of dependencies in complex type class hierarchies is still on the way. It isn't obvious how do to this nicely, as in most cases type class declarations are imported from other libraries, and you don't always have source files for them. Anyway, graphtype is fairly usable. Leave here your questions, suggestions and have fun looking at type dependencies in your code. WBR, Max

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ANNOUNCE: OAuth library in haskell
by Diego Souza 24 Aug '09

24 Aug '09

Dear Haskellers, hoauth is a library which helps you to deal with oauth protocol. Currently it supports only consumer side applications, but there are plans to add service providers support in near future. The source code can be found at [darcs]: http://projects.bitforest.org/hoauth/ and now in hackage: http://hackage.haskell.org/package/hoauth If you have any questions, comments or criticism, please get in touch with me. I'll appreciate it very much, specially because there are so many things yet to learn. Thanks, PS: This is the first piece of code I produce in Haskell since I've start learning it few months ago. I must say it has been a joy since then. -- ~dsouza yahoo!im: paravinicius gpg key fingerprint: 71B8 CE21 3A6E F894 5B1B 9ECE F88E 067F E891 651E

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ANN: haskell-src-exts-1.1.3
by Niklas Broberg 23 Aug '09

23 Aug '09

Fellow Haskelleers, I'm pleased to announce the release of haskell-src-exts-1.1.3. * On hackage: http://hackage.haskell.org/package/haskell-src-exts * Via darcs: darcs get http://code.haskell.org/haskell-src-exts * Report bugs: http://trac.haskell.org/haskell-src-exts haskell-src-exts is a package for Haskell source code manipulation. In particular it defines an abstract syntax tree representation, and a parser and pretty-printer to convert between this representation and String. It handles (almost) all syntactic extensions to the Haskell 98 standard implemented by GHC, and the parsing can be parametrised on what extensions to recognise. haskell-src-exts-1.1.3 is a highly experimental release, which (apart from a small bug fix, see below) doesn't do anything at all to the current stable part of haskell-src-exts. But the release is far from as boring as all that may sound, as it includes a whole new set of modules implementing a new and more accurate syntax tree where all nodes are adorned with annotations. Together with this comes a parser that retains exact source information, stored in the aforementioned annotations. There is also support for various precision for source information, including SrcSpans. The new modules mirror the ones in the stable part of haskell-src-exts but instead live in Language.Haskell.Exts.Annotated{.Syntax,.Parser,...} (except that SrcLoc and friends now have their own module). The point of this release is that those of you that for one reason or other are waiting for these features can help me look, feel, test and comment these things in isolation, and hopefully report a lot of bugs, before I integrate this stuff with the main haskell-src-exts body of code. Note that that coming integration is intended to be backwards-compatible, but a lot of the behind-the-scenes will be switched over to the new and more general machinery. Feature-wise, with this accurate source tree in hand, the next step is to write a printer that uses the full location information to allow full and exact round-tripping, i.e. (print . parse == id). == haskell-src-exts-1.1.3 == * Adds support for more accurate, and fully annotated, abstract syntax, see above. * Fixes a bug that forced 'rec' statement groups to end with a qualifier (like 'do'). Cheers and Happy Haskelling, /Niklas

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