March 2011 - Haskell - Haskell.org

LOPSTR 2011 - Submission deadline extended: April 17 (both full papers and extended abstracts)
by German Vidal 28 Mar '11

28 Mar '11

News: - Due to multiple requests, the submission deadlines for both full papers and extended abstracts have been extended: * Paper submission: April 17, 2011 * Extended abstract submission: April 17, 2011 ============================================================ Call for papers 21th International Symposium on Logic-Based Program Synthesis and Transformation LOPSTR 2011 http://users.dsic.upv.es/~lopstr11/ Odense, Denmark, July 18-20, 2011 (co-located with PPDP 2011, AAIP 2011 and WFLP 2011) ============================================================ Objectives: The aim of the LOPSTR series is to stimulate and promote international research and collaboration on logic-based program development. LOPSTR is open to contributions in logic-based program development in any language paradigm. LOPSTR has a reputation for being a lively, friendly forum for presenting and discussing work in progress. Formal proceedings are produced only after the symposium so that authors can incorporate this feedback in the published papers. The 21st International Symposium on Logic-based Program Synthesis and Transformation (LOPSTR 2011) will be held in Odense, Denmark; previous symposia were held in Hagenberg, Coimbra, Valencia, Lyngby, Venice, London, Verona, Uppsala, Madrid, Paphos, London, Venice, Manchester, Leuven, Stockholm, Arnhem, Pisa, Louvain-la-Neuve, and Manchester (you might have a look at the contents of past LOPSTR symposia). LOPSTR 2011 will be co-located with PPDP 2011 (International ACM SIGPLAN Symposium on Principles and Practice of Declarative Programming). Topics: Topics of interest cover all aspects of logic-based program development, all stages of the software life cycle, and issues of both programming- in-the-small and programming-in-the-large. Papers describing applications in these areas are especially welcome. Contributions are welcome on all aspects of logic-based program development, including, but not limited to: - specification - synthesis - verification - transformation - analysis - optimisation - specialization - partial evaluation - inversion - composition - program/model manipulation - certification - security - transformational techniques in SE - applications and tools Survey papers, that present some aspect of the above topics from a new perspective, and application papers, that describe experience with industrial applications, are also welcome. Papers must describe original work, be written and presented in English, and must not substantially overlap with papers that have been published or that are simultaneously submitted to a journal or a conference with refereed proceedings. Work that already appeared in unpublished or informally published workshops proceedings may be submitted. Following past editions, the formal post-conference proceedings will be published by Springer in the Lecture Notes in Computer Science (LNCS) series. IMPORTANT DATES AND SUBMISSION GUIDELINES: - Paper submission: April 17, 2011 - Extended abstract submission: April 17, 2011 - Notification (for pre-proceedings): May 26, 2011 - Camera-ready (for pre-proceedings): June 19, 2011 - Symposium: July 18-20, 2011 Submissions can either be (short) extended abstracts or (full) papers whose length should not exceed 9 and 15 pages (including references), respectively. Submissions must be formatted in the Lecture Notes in Computer Science style (excluding well-marked appendices not intended for publication). Referees are not required to read the appendices, and thus papers should be intelligible without them. Short papers may describe work-in-progress or tool demonstrations. Both short and full papers can be accepted for presentation at the symposium and will then appear in the LOPSTR 2011 pre-proceedings. Full papers can also be immediately accepted for publication in the formal proceedings to be published by Springer in the LNCS series. In addition, after the symposium, the programme committee will select further short or full papers presented in LOPSTR 2011 to be considered for formal publication. These authors will be invited to revise and/or extend their submissions in the light of the feedback solicited at the symposium. Then after another round of reviewing, these revised papers can also be published in the formal proceedings. Invited speakers: - John Gallagher, Roskilde University, Denmark - Fritz Henglein, University of Copenhagen, Denmark (shared with PPDP) - Vitaly Lagoon, Cadence Design Systems, Boston, USA (shared with PPDP) Program Committee: Elvira Albert (Complutense University of Madrid, Spain) Malgorzata Biernacka (University of Wroclaw , Poland) Manuel Carro (Technical University of Madrid, Spain) Michael Codish (Ben-Gurion University of the Negev, Israel) Danny De Schreye (K.U.Leuven, Belgium) Maribel Fernandez (King's College London, UK) Raul Gutierrez (University of Illinois at Urbana-Champaign, USA) Mark Harman (University College London, UK) Frank Huch (C.A.U. Kiel, Germany) Michael Leuschel (University of Dusseldorf, Germany) Yanhong Annie Liu (State University of New York at Stony Brook, USA) Kazutaka Matsuda (Tohoku University, Japan) Fred Mesnard (Universite de La Reunion, France) Ulrich Neumerkel (Technical University of Wien, Austria) Alberto Pettorossi (Universita' di Roma Tor Vergata, Italy) Carla Piazza (University of Udine, Italy) Peter Schneider-Kamp (University of Southern Denmark, Denmark) Hirohisa Seki (Nagoya Institute of Technology, Japan) Josep Silva (Technical University of Valencia, Spain) German Vidal (Technical University of Valencia, Spain) Jurgen Vinju (Centrum Wiskunde & Informatica, The Netherlands) Jianjun Zhao (Shanghai Jiao Tong University, Shanghai) Contacts Program Chair (contact him for additional information about papers and submissions): German Vidal Department of Computer Science (DSIC) Universitat Politecnica de Valencia Valencia, Spain Email: lopstr11(a)dsic.upv.es General Chair Peter Schneider-Kamp Dept. of Mathematics and Computer Science University of Southern Denmark Campusvej 55 DK-5230 Odense M, Denmark Email: petersk(a)imada.sdu.dk

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ANNOUNCE: GHC version 7.0.3
by Ian Lynagh 27 Mar '11

27 Mar '11

============================================================= The (Interactive) Glasgow Haskell Compiler -- version 7.0.3 ============================================================= The GHC Team is pleased to announce a new patchlevel release of GHC. This release contains a handful of bugfixes relative to 7.0.2, so we recommend upgrading. The release notes are here: http://www.haskell.org/ghc/docs/7.0.3/html/users_guide/release-7-0-3.html How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: http://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://hackage.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: http://hackage.haskell.org/trac/ghc/wiki/Contributors Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: http://hackage.haskell.org/trac/ghc/wiki/Building Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: http://hackage.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: http://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: http://www.haskell.org/ghc/reportabug

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Call for Papers: Conference on Domain-Specific Languages (DSL 2011)
by Emilie Balland 26 Mar '11

26 Mar '11

============================ Call for Papers ============================ DSL 2011: Conference on Domain-Specific Languages (IFIP sponsorship pending approval) 6-8 September 2011, Bordeaux, France http://dsl2011.bordeaux.inria.fr/ CALL FOR PAPERS Domain-specific languages have long been a popular way to shorten the distance from ideas to products in software engineering. On one hand, the interface of a DSL lets domain experts express high-level concepts succinctly in familiar notation, such as grammars for text or scripts for animation, and often provides guarantees and tools that take advantage of the specifics of the domain to help write and maintain these particular programs. On the other hand, the implementation of a DSL can automate many tasks traditionally performed by a few experts to turn a specification into an executable, thus making this expertise available widely. Overall, a DSL thus mediates a collaboration between its users and implementers that results in software that is more usable, more portable, more reliable, and more understandable. These benefits of DSLs have been delivered in domains old and new, such as signal processing, data mining, and Web scripting. Widely known examples of DSLs include Matlab, Verilog, SQL, LINQ, HTML, OpenGL, Macromedia Director, Mathematica, Maple, AutoLisp/AutoCAD, XSLT, RPM, Make, lex/yacc, LaTeX, PostScript, and Excel. Despite these successes, the adoption of DSLs have been stunted by the lack of general tools and principles for developing, compiling, and verifying domain-specific programs. General support for building and using DSLs is thus urgently needed. Languages that straddle the line between the domain-specific and the general-purpose, such as Perl, Tcl/Tk, and JavaScript, suggest that such support be based on modern notions of language design and software engineering. The goal of this conference, following the last one in 2009, is to explore how present and future DSLs can fruitfully draw from and potentially enrich these notions. We seek research papers on the theory and practice of DSLs, including but not limited to the following topics. * Foundations, including semantics, formal methods, type theory, and complexity theory * Language design, including concrete syntax, semantics, and types * Software engineering, including domain analysis, software design, and round-trip engineering * Modularity and composability of DSLs * Software processes, including metrics for software and language evaluation * Implementation, including parsing, compiling, program generation, program analysis, transformation, optimization, and parallelization * Reverse engineering, re-engineering, design discovery, automated refactoring * Hardware/software codesign * Programming environments and tools, including visual languages, debuggers, testing, and verification * Teaching DSLs and the use of DSLs in teaching * Case studies in any domain, especially the general lessons they provide for DSL design and implementation The conference will include a visit to the city of Bordeaux, a tour and tasting at the wine museum and cellar, and a banquet at La Belle Époque. INSTRUCTIONS FOR AUTHORS Papers will be judged on the depth of their insight and the extent to which they translate specific experience into general lessons for software engineers and DSL designers and implementers. Where appropriate, papers should refer to actual languages, tools, and techniques, provide pointers to full definitions, proofs, and implementations, and include empirical results. Proceedings will be published in Electronic Proceedings in Theoretical Computer Science (http://info.eptcs.org/) Submissions and final manuscripts should be at most 25 pages in EPTCS format. IMPORTANT DATES * 2011-04-18: Abstracts due * 2011-04-25: Submissions due * 2011-06-10: Authors notified of decisions * 2011-07-11: Final manuscripts due * 2011-09-05: Distilled tutorials * 2011-09-06/2011-09-08: Main conference PROGRAM COMMITTEE * Emilie Balland (INRIA) * Olaf Chitil (University of Kent) * Zoé Drey (IRIT) * Nate Foster (Cornell University) * Mayer Goldberg (Ben-Gurion University) * Shan Shan Huang (LogicBlox) * Sam Kamin (University of Illinois at Urbana-Champaign) * Jerzy Karczmarczuk (University of Caen) * Jan Midtgaard (Aarhus University) * Keiko Nakata (Tallinn University of Technology) * Klaus Ostermann (University of Marburg) * Jeremy Siek (University of Colorado at Boulder) * Tony Sloane (Macquarie University) * Josef Svenningsson (Chalmers University of Technology) * Paul Tarau (University of North Texas) * Dana N. Xu (INRIA) ORGANIZERS Local chair: Emilie Balland (INRIA) Program chairs: Olivier Danvy (Aarhus University), Chung-chieh Shan (Rutgers University) ------------------------------------------------------------------------

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Last CFP: 4th Workshop on Approaches and Applications of Inductive Programming (AAIP 2011)
by Emanuel Kitzelmann 25 Mar '11

25 Mar '11

LAST CALL FOR PAPERS 4th International Workshop on Approaches and Applications of Inductive Programming AAIP 2011 July 19, 2011, Odense, Denmark http://www.cogsys.wiai.uni-bamberg.de/aaip11/ NEWS * Due date for paper submission approaching: April 3, 2011 * Invited speaker announced: Rastislav Bodik, UC Berkeley, USA AAIP 2011 is co-located with the * the International ACM SIGPLAN Symposium on Principles and Practice of Declarative Programming (PPDP 2011), * the International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2011), and * the Workshop on Functional and (Constraint) Logic Programming (WFLP 2011) AIMS AND SCOPE Inductive program synthesis or inductive programming (IP) is concerned with the automated generation of (parts of) computer programs from incomplete specifications such as input/output examples. IP particularly includes the synthesis of programs that contain loops or recursive calls. This inductive type of automated program synthesis is addressed by researchers in different fields such as artificial intelligence, evolutionary computation, inductive inference, formal methods, functional programming, and inductive logic programming. The aim of the AAIP workshop is to have a common place to present and discuss research on all aspects of inductive programming - including, but not limited to: Inductive programming algorithms, techniques, and systems, heuristics, inductive biases, analysis of the learnability of particular program classes, and the integration of different techniques. We especially encourage submissions on relevant challenge problems and on real-world applications of inductive programming in, e.g., computer-assisted software development, end-user programming, and intelligent agents. This is the fourth workshop on "Approaches and Applications of Inductive Programming" and takes place for the first time in conjunction with PPDP and LOPSTR. We invite authors to submit papers reporting on original work in either of two categories: full technical papers and short papers. Full papers should present mature work. Short papers may be work in progress reports, descriptions of system demonstrations, or position statements. INVITED SPEAKER Rastislav Bodik, University of California, Berkeley, USA PRESENTATION AND PUBLICATION INFORMATION All accepted papers will be presented orally. Workshop (pre-)proceedings will be published online and as a technical report. Furthermore, we plan to publish selected and revised papers as a formal post-proceedings volume, most likely in the Springer LNCS series. SUBMISSION GUIDELINES Submitted papers must describe original work, be written in English and should be formatted in the Springer Lecture Notes in Computer Science style: http://www.springer.de/comp/lncs/authors.html Submissions can either be full papers describing mature work or short papers describing work in progress, a system demonstration, or make a position statement. Full and short papers should not exceed 16 and 8 pages, respectively, including bibliography and appendices. Papers should be submitted as PDF via the AAIP 2011 submission webpage: http://www.easychair.org/conferences/?conf=aaip2011 IMPORTANT DATES April 3, 2011 Paper submission May 16, 2011 Author notification June 12, 2011 Camera-ready July 19, 2011 Workshop ORGANIZATION COMMITTEE * Emanuel Kitzelmann, International Computer Science Institute, Berkeley, USA * Ute Schmid, University of Bamberg, Germany PROGRAM COMMITTEE * Ricardo Aler Mur, Universidad Carlos III de Madrid, Spain * Pierre Flener, Uppsala University, Sweden * Lutz Hamel, University of Rhode Island, Kingston, USA * Jose Hernandez-Orallo, Technical University of Valencia, Spain * Martin Hofmann, SAP Research & Development, Germany * Johan Jeuring, University of Utrecht, The Netherlands * Susumu Katayama, University of Miyazaki, Japan * Pieter Koopman, Radboud University Nijmegen, The Netherlands * Maria Jose Ramirez Quintana, Technical University of Valencia, Spain CONTACT aaip2011(a)easychair.org -- Dr. Emanuel Kitzelmann International Computer Science Institute (ICSI) 1947 Center Street, Suite 600 Berkeley, CA 94704, USA e-mail: emanuel(a)icsi.berkeley.edu phone: +1 510 666 2883

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ANNOUNCE: c2hs 0.16.3
by Duncan Coutts 24 Mar '11

24 Mar '11

All, c2hs version 0.16.3 is out and is available from hackage http://hackage.haskell.org/package/c2hs What is c2hs ============ c2hs is an FFI preprocessor tool, a bit like hsc2hs, that helps with the development of Haskell bindings to C libraries. The major advantages of using c2hs compared to writing foreign imports by hand (or using hsc2hs) are: * Cross-language type safety: C functions are imported with the correct Haskell types. * Saves time: boilerplate marshaling code is generated. It works by extracting interface information from C header files and it generates Haskell code with foreign imports and marshalling. Changes in this release ======================= * In and out marshallers may now have arguments, rather than just being single function names. * Foreign function imports will now use stdcall if the C headers specify this calling convention. This will help with bindings to some C libraries on Windows. * New {# alignof #} hook, like the existing {# sizeof #} hook. This is useful for the alignment in Storable instances. * Fewer marshalling functions are needed from the bundled C2HS module. The trend is towards eliminating the need for any axillary marshalling module. Credits ======= Thanks to Jonathan Rockway, ron(a)gamr7.com and Dmitry Astapov for contributions to this release. Links ===== Home page: http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ Bug tracker: http://hackage.haskell.org/trac/c2hs/ Duncan

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Haskell Weekly News: Issue 174
by Daniel Santa Cruz 24 Mar '11

24 Mar '11

Welcome to issue 174 of the HWN, a newsletter covering developments in the [1]Haskell community. This release covers the week of March 13-19. You can find the HTML version at: http://bit.ly/hLu36R Announcements JP Moresmau [2]announced a new release of EclipseFP with support for ghc 7! S. Doaitse Swierstra [3]announced the release of version 2.7.0 to the uu-parsinglib library to hackage. Vincent Gerard [4]informed us that he has taken over maintainership of hsmagick, which is "a FFI bindings library to ImageMagick." He is pleased to announce the 0.5 release of the library. Malte Harder [5]announce the first release of the Craftwerk graphics library for 2d vector graphics. Corey O'Connor [6]annouced a new release of his VTY library. Brent Yorgey [7]announced the release of the special Poetry and Fiction Edition of The Monad.Reader. Thanks for putting this together Brent! Gregory D. Weber [8]announced version 1.2.4 of his Sifflet and sifflet-lib. "This is a compatibility release for HXT >= 9.1." Edward Kmett [9]remminded us that the Google Summer of Code is upon us. Follow the link to see the sign up information. Quotes of the Week * ddarius: *ddarius is more of a glass SUM_n (-1)^n full person. * monochrom: some kind of lazy evaluation is already known to highschool kids. teachers tell you that in a*(b+c), "evaluate b+c first", right? well, I challenge you to take 0*(389238493+97283748) and find one single student who faithfully evaluate 389238493+97283748 first. * hpc: in soviet russia, yoda speaks flawless english * lambdabot: trololololo * hpc: jokes are subject to an incompleteness theorem; if you can prove they are funny, they were never good jokes to begin with * hpc: when all you have is Haskell, everything looks like a research paper * Edward Kmett:Clearly we need some sort of xbox live-like achievement system for these. Achievement Unlocked: Stumped Oleg! Top Reddit Stories * Haskell.org has been accepted for the 2011 Google Summer of Code From (twitter.com) scored 48 with 1 comments. Read on [10]reddit. Read the [11]original post. * Haskell's Niche: Hard Problems From (cdsmith.wordpress.com) scored 47 with 17 comments. Read on [12]reddit. Read the [13]original post. * A little care and feeding can go a long way From (serpentine.com) scored 39 with 6 comments. Read on [14]reddit. Read the [15]original post. * The reception of monads circa 1995... From (self.haskell), scored 35 with 1 comments. Read on [16]reddit. * BlazeHtml: a blazingly fast HTML combinator library From (skillsmatter.com) scored 29 with 18 comments. Read on [17]reddit. Read the [18]original post. * Simon Peyton Jones: Managing parallelism: embrace diversity, but control side effects From (skillsmatter.com) scored 28 with 12 comments. Read on [19]reddit. Read the [20]original post. * EZYang: Mutation is frequently not what people expect ; mutation is not modular, and mutation is complicated. From (blog.ezyang.com) scored 26 with 0 comments. Read on [21]reddit. Read the [22]original post. * Functor is to Lens as Applicative is to Biplate: Introducing Multiplate From (front.math.ucdavis.edu) scored 25 with 19 comments. Read on [23]reddit. Read the [24]original post. * Monad.Reader special poetry and fiction edition From (themonadreader.wordpress.com) scored 23 with 1 comments. Read on [25]reddit. Read the [26]original post. * Functional flocks : modelling and visualizing flocking behavior in Haskell From (syntacticsalt.com) scored 22 with 0 comments. Read on [27]reddit. Read the [28]original post. Top StackOverflow Answers * [29]Why does application of `sequence` on List of Lists lead to computation of its Cartesian Product? votes: 12 This works because using lists as monads in Haskell makes them model indeterminism. Consider: sequence [[1,2],[3,4]] By definition this is the same as: do x <- [1,2] y <- [3,4] return [x,y] Just read it as "First a choice between 1 and 2, then a choice between 3 and 4". The list monad will now accumulate all possible outcomes - hence the ... * [30]In GHCi, why does the kind of the function arrow `:kind (->)` include question marks `(->) :: ?? -&ht; ? -> *`? votes: 11 The ? and ?? kinds refer to GHC extensions, specifically unboxed types. http://hackage.haskell.org/trac/ghc/wiki/IntermediateTypes has a diagram showing relationships between the extended kinds ? (all possible types), # (unboxed types), ?? (boxed or normal unboxed types â "least upper bound of # and *"), (#) (unboxed tuples, which can only be used in a ... * [31]How to use (->) instances of Monad and confusion about (->) votes: 11 For a given type r, the function of type r -> a can be thought of as a computation delivering an a using an environment typed r. Given two functions r -> a and a -> (r -> b), it's easy to imagine that one can compose these when given an environment (again, of type r). But wait! That's exactly what monads are about! So we can create an instance ... * [32]How and why is ap defined as liftM2 id in Haskell votes: 10 The type variable a from id can be instantiated at any type, and in this case that type is a -> b. So we are instantiating id at (a -> b) -> (a -> b). Now the type variable a1 from liftM2 is being instantiated at (a -> b), a2 is being instantiated at a, and r is being instantiated at b. Putting it all together, liftM2 is instantiated at ... * [33]What "reify" and "reification" means in the context of (functional?) programming? votes: 8 So I read up on this, and it is pretty much what it means: taking an abstract concept and making it concrete. Or, there is a proxy that represents the abstract concept. For example, in Lisp, the concept of procedure abstraction and application is reified when you use lambdas. Reification by itself is a broad concept and not just applicable to functional ... Top StackOverflow Questions * [34]What "reify" and "reification" means in the context of (functional?) programming? votes: 17, answers: 6 * [35]How to use (->) instances of Monad and confusion about (->) votes: 12, answers: 2 * [36]In GHCi, why does the kind of the function arrow `:kind (->)` include question marks `(->) :: ?? -> ? -> *`? votes: 12, answers: 1 * [37]Haskell-like type system in C votes: 11, answers: 2 * [38]Write a Maximum Monoid using Maybe in Haskell votes: 9, answers: 1 About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstcruz(a)gmail.com. I'm in dire need of finding good "quotes of the week". If you happen to come across any, please don't hesitate to send it along. Until next time, Daniel Santa Cruz References 1. http://haskell.org/ 2. http://jpmoresmau.blogspot.com/2011/03/eclipsefp-204-released-supports-ghc-… 3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/87205 4. http://article.gmane.org/gmane.comp.lang.haskell.general/18564 5. http://article.gmane.org/gmane.comp.lang.haskell.general/18568 6. http://article.gmane.org/gmane.comp.lang.haskell.general/18574 7. http://article.gmane.org/gmane.comp.lang.haskell.general/18572 8. http://article.gmane.org/gmane.comp.lang.haskell.general/18584 9. http://article.gmane.org/gmane.comp.lang.haskell.cafe/87399 10. http://www.reddit.com/r/haskell/comments/g6nwe/haskellorg_has_been_accepted… 11. http://twitter.com/haskellorg/status/48838580029755392 12. http://www.reddit.com/r/haskell/comments/g382d/haskells_niche_hard_problems/ 13. http://cdsmith.wordpress.com/2011/03/13/haskells-niche-hard-problems/ 14. http://www.reddit.com/r/haskell/comments/g6a01/a_little_care_and_feeding_ca… 15. http://www.serpentine.com/blog/2011/03/18/a-little-care-and-feeding-can-go-… 16. http://www.reddit.com/r/haskell/comments/g4f1m/the_reception_of_monads_circ… 17. http://www.reddit.com/r/haskell/comments/g7akc/blazehtml_a_blazingly_fast_h… 18. http://skillsmatter.com/podcast/scala/blazehtml-a-blazingly-fast-html-combi… 19. http://www.reddit.com/r/haskell/comments/g7ajj/simon_peyton_jones_managing_… 20. http://skillsmatter.com/podcast/scala/talk-by-haskell-expert-simon-peyton-j… 21. http://www.reddit.com/r/haskell/comments/g3dsw/ezyang_mutation_is_frequentl… 22. http://blog.ezyang.com/2011/03/killer-mutants-attack-mutation-gone-wrong/ 23. http://www.reddit.com/r/haskell/comments/g56xw/functor_is_to_lens_as_applic… 24. http://front.math.ucdavis.edu/1103.2841 25. http://www.reddit.com/r/haskell/comments/g4r6e/monadreader_special_poetry_a… 26. http://themonadreader.wordpress.com/2011/03/15/special-poetry-and-fiction-e… 27. http://www.reddit.com/r/haskell/comments/g2v75/functional_flocks_modelling_… 28. http://syntacticsalt.com/2011/03/10/functional-flocks/ 29. http://stackoverflow.com/questions/5299295/why-does-application-of-sequence… 30. http://stackoverflow.com/questions/5359707/in-ghci-why-does-the-kind-of-the… 31. http://stackoverflow.com/questions/5310203/how-to-use-instances-of-monad-an… 32. http://stackoverflow.com/questions/5358868/how-and-why-is-ap-defined-as-lif… 33. http://stackoverflow.com/questions/5314884/what-reify-and-reification-means… 34. http://stackoverflow.com/questions/5314884/what-reify-and-reification-means… 35. http://stackoverflow.com/questions/5310203/how-to-use-instances-of-monad-an… 36. http://stackoverflow.com/questions/5359707/in-ghci-why-does-the-kind-of-the… 37. http://stackoverflow.com/questions/5290408/haskell-like-type-system-in-c 38. http://stackoverflow.com/questions/5344164/write-a-maximum-monoid-using-may…

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ANN: clash-0.1.3.0 (Functional Hardware Descriptions)
by Christiaan Baaij 23 Mar '11

23 Mar '11

Hello, I am pleased to announce an incremental update to CLaSH, version 0.1.3.0. CLaSH can translate a (semantic) subset of Haskell to RTL-style VHDL. Instead of being an embedded DSL like Lava or ForSyDe, CLaSH takes are more 'traditional' approach to synthesis/compilation. It uses the GHC API as a front-end for parsing, type-checking and desugaring the Haskell source. It then exhaustively applies a list of meaning-preserving transformations to the intermediate GHC Core representation until it is in the desired normal form. The normalized Core/System Fc is then 'trivially' translated to RTL-style VHDL. The new version of CLaSH has the following updates: - Support for simulation and synthesis of multi-clock hardware [6] - Significant synthesis speed-up (4x to 10x) CLaSH already supported synthesis of: - User-defined Higher-Order functions [1] - User-defined ADTs (GADTs are not tested, but *might* work) - All of Haskell's choice constructs (Guards, Pattern Matching, etc.) - Lambda-abstraction / Anonymous Functions You can use CLaSH as a library, but the use of the adapted GHC interpreter (added the :vhdl command) is recommended. The interpreter can be found on the CLaSH website [2], where you will also find examples, papers, tutorials, etc. The library can be downloaded from Hackage [3]. I recently gave a demo of CLaSH at the DATE'11 conference in grenoble, this demo already made use of the multi-clock feature (and is actually the only reference if you want to experiment with multi-clock hardware yourself). The source for the demo (audio spectrum analyzer programmed on an Altera Cyclone II FPGA board) can be downloaded from my github page [4]. Do note that CLaSH only works when you have the 6.12.* branch of GHC installed! I am currently analyzing the impact of the GHC API changes made in the 7.0.* brach, and hope to make the transition to the new API within the next month. Although the compiler is already used by 2 other phd's in our group [5], it is not a thoroughly tested product, so your coding style might not be anticipated by the current version of CLaSH ;-) -- Christiaan Baaij [1] There is hard-coded support for a set of recursively defined higher-order functions such as map, fold, zipWith, etc. [2] http://clash.ewi.utwente.nl [3] http://hackage.haskell.org/package/clash-0.1.3.0 [4] http://github.com/christiaanb/DE1-Cyclone-II-FPGA-Board-Support-Package [5] http://caes.ewi.utwente.nl [6] Simulation does not show meta-stability, you will have to take care of synchronization (dual flipflop) yourself

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Re: [Haskell] ANNOUNCE: incremental-parser library package
by Mario Blažević 22 Mar '11

22 Mar '11

2011/3/22 Philippa Cowderoy <postmaster(a)flippac.org> > This is what newtypes are for, no? > I did not think of that approach. I'm not sure how well it would work out, but it would solve another problem I have, which is the duplication of combinators many, some, and optional. Each of these could exist in two forms, the lazy one and the greedy one, and the only difference is the underlying choice combinator, (<|>) vs. (<<|>). I'm not aware of any other parsing library taking this road, though, and there must be a good reason. I'll try and see. > 2011/3/22 Mario Blažević <mblazevic(a)stilo.com> > >> >> This seems very interesting. One question: >>> >>> > The MonadPlus and the Alternative instance differ: the former's mplus >>> > combinator equals the asymmetric <<|> choice. >>> >>> Why? >>> >> >> >> Good question. Basically, I see MonadPlus as a union of Monad and >> Alternative. The class should not exist at all. But as long as it does, I >> figured I should provide an instance, and I made it different from the >> Monoid+Alternative combination because otherwise it would be useless. My >> second choice would be to remove the instance completely. >> > > I have to admit I really do not like having Applicative and MonadPlus with > different behavior. Yes, one is redundant, but that is more an artifact of > language evolution, than an intentional opportunity for diverging behavior. > > Every library I am aware of to date, save of course this one, has > maintained their compatibility. > > If the instance for Alternative satisfies the underspecified MonadPlus > laws, I'd just as soon have the 'useless redundant' instance. The power of > MonadPlus is in the combinators that are built on top of it. Not in the > primitives themselves. > > If the Alternative instance would not be a legal MonadPlus instance, then > I'd feel much less queasy with your second scenario, and it simply removed. > > -Edward >

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ANNOUNCE: incremental-parser library package
by Mario Blažević 22 Mar '11

22 Mar '11

The first version of incremental-parser has been released on Hackage [1]. It's yet another parser combinator library, providing the usual set of Applicative and Monad combinators. Apart from this, it has three twists that make it unique. First, the parser is incremental. That means it can be fed its input in chunks, and in proper circumstances it can also provide the parsed output in chunks. For this to be possible the result type must be a Monoid. The complete parsing result is then a concatenation of the partial results. In order to make the incremental parsing easier, the combinator set is optimized for monoidal results. The usual combinator many1, for example, assumes the result type is a monoid and concatenates its components instead of constructing a list. In Parsec: > many1 :: Stream s m t => ParsecT s u m a -> ParsecT s u m [a] In incremental-parser: > many1 :: (Monoid s, Monoid r) => Parser s r -> Parser s r The second weirdness is that the the parser is generic in its input stream type, but this type is parameterized in a holistic way. There is no separate token type. Primitive parsers that need to peek into the input require its type to be an instance of a monoid subclass. In Parsec: > string :: Stream s m Char => String -> ParsecT s u m String > char :: Stream s m Char => Char -> ParsecT s u m Char > anyToken :: (Stream s m t, Show t) => ParsecT s u m t In Attoparsec: > string :: ByteString -> Parser ByteString > word8 :: Word8 -> Parser Word8 > anyWord8 :: Parser Word8 In incremental-parser: > string :: (LeftCancellativeMonoid s, MonoidNull s) => s -> Parser s s > token :: (Eq s, FactorialMonoid s) => s -> Parser s s > anyToken :: FactorialMonoid s => Parser s s The monoid subclasses referenced above provide methods for analyzing and subdividing the input stream. The classes are not particularly demanding, and any reasonable input stream should be able to accommodate them easily. The library comes with instances for lists, ByteString, and Text. > class Monoid m => MonoidNull m where > mnull :: m -> Bool > class Monoid m => LeftCancellativeMonoid m where > mstripPrefix :: m -> m -> Maybe m > class Monoid m => FactorialMonoid m where > factors :: m -> [m] > primePrefix :: m -> m > ... Finally, the library being implemented on the basis of Brzozowski derivatives, it can provide both the symmetric and the left-biased choice, <|> and <<|>. This is the same design choice made by Text.ParserCombinators.ReadP and uu-parsinglib. Parsec and its progeny on the other hand provide only the faster left-biased choice, at some cost to the expressiveness of the combinator language. [1] http://hackage.haskell.org/package/incremental-parser-0.1

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ANN: ListLike-3.1.0
by John Lato 22 Mar '11

22 Mar '11

Hello, I am pleased to announce an incremental update to the ListLike package, version 3.1.0. This version adds newtype wrappers for strict and lazy ByteStrings, CharString and CharStringLazy, as well as instances of the form: instance ListLike CharString Char where ... These instances allow access to Data.ByteString.Char8 functions via the ListLike interface. Most importantly, you can now use uu-parsinglib to parse ASCII-based bytestrings via the newtype wrapper, as in: parseByteString bytestring charParser = parse charParser $ createStr (LineColPos 0 0 0) (CS bs) Thanks to S Doaitse Swierstra for making this possible via the excellent uu-parsinglib library. John L.

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