April 2013 - Haskell - Haskell.org

Call for Contributions - Haskell Communities and Activities Report, May 2013 edition
by Janis Voigtländer 08 Apr '13

08 Apr '13

Dear all, I would like to collect contributions for the 24th edition of the ================================================================ Haskell Communities & Activities Report http://www.haskell.org/haskellwiki/Haskell_Communities_and_Activities_Report Submission deadline: 1 May 2013 (please send your contributions to hcar at haskell.org, in plain text or LaTeX format) ================================================================ This is the short story: * If you are working on any project that is in some way related to Haskell, please write a short entry and submit it. Even if the project is very small or unfinished or you think it is not important enough --- please reconsider and submit an entry anyway! * If you are interested in an existing project related to Haskell that has not previously been mentioned in the HCAR, please tell me, so that I can contact the project leaders and ask them to submit an entry. * Feel free to pass on this call for contributions to others that might be interested. More detailed information: The Haskell Communities & Activities Report is a bi-annual overview of the state of Haskell as well as Haskell-related projects over the last, and possibly the upcoming six months. If you have only recently been exposed to Haskell, it might be a good idea to browse the previous edition --- you will find interesting projects described as well as several starting points and links that may provide answers to many questions. Contributions will be collected until the submission deadline. They will then be compiled into a coherent report that is published online as soon as it is ready. As always, this is a great opportunity to update your webpages, make new releases, announce or even start new projects, or to talk about developments you want every Haskeller to know about! Looking forward to your contributions, Janis (current editor) FAQ: Q: What format should I write in? A: The required format is a LaTeX source file, adhering to the template that is available at: http://haskell.org/communities/05-2013/template.tex There is also a LaTeX style file at http://haskell.org/communities/05-2013/hcar.sty that you can use to preview your entry. If you do not know LaTeX, then use plain text. If you modify an old entry that you have written for an earlier edition of the report, you should already have received your old entry as a template (provided I have your valid email address). Please modify that template, rather than using your own version of the old entry as a template. Q: Can I include Haskell code? A: Yes. Please use lhs2tex syntax (http://people.cs.uu.nl/andres/lhs2tex/) The report is compiled in mode polycode.fmt. Q: Can I include images? A: Yes, you are even encouraged to do so. Please use .jpg format, then. Q: Should I send files in .zip archives or similar? A: No, plain file attachements are the way. Q: How much should I write? A: Authors are asked to limit entries to about one column of text. A general introduction is helpful. Apart from that, you should focus on recent or upcoming developments. Pointers to online content can be given for more comprehensive or "historic" overviews of a project. Images do not count towards the length limit, so you may want to use this opportunity to pep up entries. There is no minimum length of an entry! The report aims for being as complete as possible, so please consider writing an entry, even if it is only a few lines long. Q: Which topics are relevant? A: All topics which are related to Haskell in some way are relevant. We usually had reports from users of Haskell (private, academic, or commercial), from authors or contributors to projects related to Haskell, from people working on the Haskell language, libraries, on language extensions or variants. We also like reports about distributions of Haskell software, Haskell infrastructure, books and tutorials on Haskell. Reports on past and upcoming events related to Haskell are also relevant. Finally, there might be new topics we do not even think about. As a rule of thumb: if in doubt, then it probably is relevant and has a place in the HCAR. You can also ask the editor. Q: Is unfinished work relevant? Are ideas for projects relevant? A: Yes! You can use the HCAR to talk about projects you are currently working on. You can use it to look for other developers that might help you. Q: If I do not update my entry, but want to keep it in the report, what should I do? A: Tell the editor that there are no changes. The old entry will typically be reused in this case, but it might be dropped if it is older than a year, to give more room and more attention to projects that change a lot. Do not resend complete entries if you have not changed them. Q: Will I get confirmation if I send an entry? How do I know whether my email has even reached the editor, and not ended up in a spam folder? A: Prior to publication of the final report, the editor will send a draft to all contributors, for possible corrections. So if you do not hear from the editor within two weeks after the deadline, it is safer to send another mail and check whether your first one was received.

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Third CfP for the International Workshop on Trends in Functional Programming In Education (TFPIE)
by p.k.f.holzenspies＠utwente.nl 08 Apr '13

08 Apr '13

L.S., Apologies for any duplicates you may receive. EasyChair now open! [3] Please find below the Third Call for Papers for the Second International Workshop on Trends in Functional Programming In Education (TFPIE). As an addendum to previous CfPs for this event, I would like you to consider the following: May FP researchers also teach FP or use an FP language to teach something else. Even though many of these teachers are very enthusiastic about what they do, they typically don't consider it something to write up. I believe that having a serious forum specifically for the education of or with FP will help promote the use of FP as a teaching tool and will benefit the field of computer science as a whole. Previous CfPs for the event were sent out in PDF form. Many mailing-lists reject this. Therefore, below, is the plain textual form of the CfP. For more information, refer to the website [1]. For inspiration, see last year's proceedings (like this year, published in the Electronic Proceedings in Theoretical Computer Science) [2]. Submissions are welcome via EasyChair [3]. Please forward this CfP to whatever forum you consider appropriate. Regards, Philip K.F. Hölzenspies Programme Committee Chair TFPIE 2013 [1] http://wwwhome.ewi.utwente.nl/~holzenspiespkf/TFPIE2013.html [2] http://rvg.web.cse.unsw.edu.au/eptcs/content.cgi?TFPIE2012 [3] https://www.easychair.org/conferences/?conf=tfpie2013 Third Call for Papers the Second International Workshop on Trends in Functional Programming in Education TFPIE ----- The second International Workshop on Trends in Functional Programming in Education, TFPIE 2013, is co-located with Trends in Functional Programming (TFP 2013) at Brigham Young University in Utah. The goal of TFPIE is to gather researchers, teachers and all professionals that use, or are interested in the use of, functional programming in education. TFPIE aims to be a venue were novel ideas, classroom-tested ideas and work-in-progress on the use of functional programming in education are discussed. The one-day workshop will foster a spirit of open discussion by having a review process for publication after the workshop. The program chair of TFPIE 2013 will screen submissions to ensure that all presentations are within scope and are of interest to participants. Potential presenters are invited to submit an extended abstract (4-6 pages) or an article (up to 16 pages) in EPTCS style. The authors of all accepted presentations will have their preprints and their slides made available on the workshop's website/wiki. Any visitors to the TFPIE 2013 website/wiki will be able to add comments. This includes presenters who may respond to comments and questions as well as provide pointers to improvements and follow-up work. After the workshop, the presenters will be invited to submit (a revised version of) their article for review. The PC will select the best articles for publication in the Electronic Proceedings in Theoretical Computer Science journal (EPTCS). Articles rejected for presentation and all extended abstracts will not be formally reviewed by the PC. TFPIE 2013 welcomes submissions describing practical techniques used in the classroom, tools used in and/or developed for the classroom and any creative use of functional programming (FP) to aid education in or outside Computer Science. Topics of interest include, but are not limited to: - Teaching FP to highschool, beginning CS, and graduate students - FP as a teaching tool for other (CS) topics - FP and Robotics, Music and Philosophy - Advanced FP for undergraduates - Engaging students in research using FP - FP in Programming Languages - FP as a stepping stone to other CS topics Important dates & Submission ---------------------------- Submission for presentation: Apr 20 Notification of acceptance: Apr 25 Submission formal paper: Jun 9 Notification of acceptance: Aug 16 Camera-ready version: Sep 8 Submission (pre-conference) through EasyChair: https://www.easychair.org/conferences/?conf=tfpie2013 Submission and review for publication occur after the meeting in Utah. This allows authors to revise their articles, to include comments received at the meeting. After submission, we aim to provide four reviews per paper. Contact ------- You can direct any questions you might have to the program chair, through tfpie2013(a)easychair.org. Discussion, both of the workshop itself and of the work presented there, is hosted on the TFPIE-wiki. Venue ----- Brigham Young University (BYU) is the third-largest private university and the largest explicitly religious university in the United States of America. Although BYU is owned and operated by the LDS church, the workshop is independent of this affiliation. By BYU's own pen: "Brigham Young University seeks to develop students of faith, intellect and character who have the skills and the desire to continue learning and to serve others throughout their lives. Established in 1875, the university provides an outstanding education in an atmosphere consistent with the ideals and principles of its sponsor, The Church of Jesus Christ of Latter-day Saints. Known for its academically minded and internationally experienced student body, its world-class teaching and its beautiful mountain location, BYU is also recognized for its extensive language programs, talented performing arts ensembles, outstanding sports programs and devotion to combining solid scholarship with the principles of the restored gospel of Jesus Christ." It should be noted that BYU's "Honor Code" applies only to students & staff. It does *not* apply to visitors. Programme Committee ------------------- Peter Achten (General co-chair), Radboud Universiteit Nijmegen, The Netherlands Edwin Brady, University of St. Andrews, Scotland Marc Feeley, Université de Montréal, Canada Matthew Flatt, University of Utah, USA Philip K.F. Hölzenspies (PC chair), Universiteit Twente, The Netherlands Gabriele Keller, University of New South Wales, Australia Jan Kuper, Universiteit Twente, The Netherlands Marco T. Morazán (General co-chair), Seton Hall University, USA Stephanie Weirich, University of Pennsylvania, USA Viktória Zsók, Eötvös Loránd Tudományegyetem, Hungary See the website for updated information: http://wwwhome.ewi.utwente.nl/~holzenspiespkf/TFPIE2013.html

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CfP: Workshop Haskell and Rewriting Techniques HART 2013
by Johannes Waldmann 07 Apr '13

07 Apr '13

Rewriting is the science of replacing equals by equals and thus a very powerful method for dealing with equations. There are strong connections between Haskell programming and rewriting. Therefore, we announce a new workshop, International Workshop on Haskell And Rewriting Techniques (HART 2013) http://www.imn.htwk-leipzig.de/HART2013/ to be held on June 27, in conjunction with RDP 2013, in Eindhoven. (RDP contains RTA, the main rewriting conference.) We plan a half day of discussions, in an informal setting, on how Haskell and rewriting techniques and theories can cross-fertilize each other. Topics of interest are, for example, equational reasoning and other rewriting techniques for program verification and analysis; lambda calculi and type systems for functional programs and higher order rewriting systems; rewriting of type expressions in the type checker; rewriting of programs by refactoring tools, optimizers, code generators; execution of programs as a form of graph rewriting; template Haskell, introducing a rewriting-like macro language into the compilation process. This list of topics is non-exclusive. If you have a contribution that connects Haskell and rewriting, then submit. When in doubt, contact a member of the PC. Program committee: Alcino Cunha (U Minho) Jürgen Giesl (RWTH Aachen) Andy Gill (U of Kansas) Johan Jeuring (U Utrecht) Keisuke Nakano (UEC Tokyo) Kristoffer H Rose (IBM Watson) (co-chair) Christian Sternagel (JAIST) Janis Voigtländer (U Bonn) Johannes Waldmann (HTWK Leipzig) (co-chair) Dates: May 6: deadline for submissions May 20: notification of acceptance June 27: workshop Submission and Proceedings: Two categories of submissions are invited: Extended abstracts. Presenting original research, and also preliminary reports of work in progress. Will be included in the proceedings. Presentation-only papers. Describing work recently published or submitted. Will not be included in the proceedings. Papers should be at most 5 pages in length, and should use the easychair.cls style. Submission is handled through the EasyChair HART2013 page, https://www.easychair.org/conferences/?conf=hart2013 In line with the informal style of the workshop, the reviewing of submissions will be light. When accepting and scheduling presentations, preference will be given to original research. Proceedings will be made available electronically at the workshop.

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ANN: psqueue-benchmarks - benchmarks of priority queue implementations
by Niklas Hambüchen 07 Apr '13

07 Apr '13

(This is a slightly detailed email. If you are the maintainer of one of the packages benchmarked here, you might want to read it though.) Today I was looking for a Priority Queue that also allows a delete operation (some call this a "Priority Search Queue"). I found http://stackoverflow.com/questions/6976559/comparison-of-priority-queue-imp… and after looking at the 10 queue alternatives, I got to the following conclusions: * Only 3 of them allow to delete entries (are p*s*queues) * Most of them are outdated or at least unmaintained for the last 3-5 years * There was an effort to get a priority queue into containers (see the stackoverflow link), but it was not agreed on * Those efforts were driven by Louis Wasserman, who wrote one of the 3 psqueues (queuelike), but now only maintains a non-ps-queue (pqueue) that seems to be the most popular priority queue implementation PSQueue implementations ----------------------- The three packages that are psqueues are: - PSQueue (http://hackage.haskell.org/package/PSQueue-1.1) * original implementation from paper of Ralf Hinze * last upload 2008 * no test suite (but small commented out QC properties), no benchmarks * no code repository - fingertree-psqueue (http://hackage.haskell.org/package/fingertree-psqueue-0.3) * last upload 2011 * no tests, no benchmarks * no code repository - queuelike (http://hackage.haskell.org/package/queuelike-1.0.9) * last upload 2009 * no tests, no benchmarks * no code repository Benchmarks ---------- Unfortunately, none of them had tests, code in repositories or any indication about their real-world performance, so I made some criterion benchmarks. You can find them here: https://github.com/nh2/psqueue-benchmarks Graphs: http://htmlpreview.github.com/?https://raw.github.com/nh2/psqueue-benchmark… Benchmark results ----------------- * PSQueue throws a stack space overflow if you try to put in 100000 Ints * PSQueue suffers from some significant worst case in terms of queue creation, sometimes creating a queue from random numbers just takes 5 times longer (1st graph). This only happens sometimes (despite Criterion) * queuelike creation is instant - it seems to work around my benchmark somehow * converting a queuelike queue to a list surprisingly takes 10 times longer than with the other packages * in terms of average performance, the three are quite close to each other (apart from the point above). queuelike seems fastest, fingertree-psqueue is second and PSQueue slowest, with a difference of +30% to the next one My questions to the maintainers ------------------------------- @Scott: Do you have an idea why PSQueue stack overflows? @Louis: Why did you switch from queuelike to pqueue? Could you put the code up somewhere manageable (repo)? Is it possible to make pqueue a full pSqueue implementation? Niklas

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DTP 2013 Call for Papers
by Stephanie Weirich 05 Apr '13

05 Apr '13

======================================================================== DTP 2013 ACM SIGPLAN Workshop on Dependently-Typed Programming SEPTEMBER 2013 Boston, Massachusetts, USA (co-located with ICFP 2013) CALL FOR PAPERS http://www.seas.upenn.edu/~sweirich/dtp13 ======================================================================== The ACM SIGPLAN Workshop on Dependently-Typed Programming 2013 will be co-located with the [2013 International Conference on Functional Programming (ICFP), in Boston, Massachusetts, USA](http://icfpconference.org/icfp2013/). The purpose of DTP is to discuss experiences with dependent types in programming and future developments for dependently-typed languages. Recent years have seen increasing overlap between the dependent type theory and functional programming languages communities. Co-locating this workshop with ICFP will promote that cross fertilization. Topics of interest include, but are not limited to: * Language Design, both in the context of possible extensions and modifications of existing languages and the development of new languages with dependent types; * Theory, such as formal treatments of semantics and type systems; * Compilation, including implementations and optimization of dependently-typed languages; * Tools, in the form of IDEs, profilers, tracers, debuggers, and testing tools; * Functional Pearls, being elegant, instructive examples of using dependent types; * Experience Reports, general practice and experience with dependently-typed languages, e.g., in an education or industry context. Workshop Format --------------- The workshop program will be composed of regular papers (formally reviewed and published by ACM, see below) and informal presentations. A separate call for informal presentations will be issued during Summer 2013. Regular papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work. Functional Pearls and Experience reports need not necessarily report original research results; they may instead, for example, report practical experience that will be useful to others, reusable programming idioms, or elegant new ways of approaching a problem. The key criterion for such a paper is that it makes a contribution from which other programmers can benefit. It is not enough simply to describe a (dependently-typed) program! Proceedings ----------- Regular papers will appear in a formal proceedings published by ACM Press. In addition to printed proceedings, accepted papers will be included in the ACM Digital Library. Authors must abide by the [ACM policy](http://www.acm.org/news/featured/author-rights-management) for rights and permissions. Authors are encouraged to publish auxiliary material with their paper (source code, test data, etc.); they always retain copyright of auxiliary material. Submission Details ------------------ * Paper Submission : Thursday, 14th June 2013 anywhere on Earth * Author Notification: Thursday, 11th July 2013 * Final Papers Due : Thursday, 25th July 2013 Submitted papers should be in portable document format (PDF), formatted using the ACM SIGPLAN style guidelines (9pt format, more details appear on the symposium web page). The length is restricted to 12 pages, except for "Experience Report" papers, which are restricted to 6 pages. Each paper submission must adhere to SIGPLAN's republication policy, as explained on the web. "Functional Pearls", and "Experience Reports" should be marked as such with those words in the title at time of submission. The paper submission deadline and length limitations are firm. There will be no extensions, and papers violating the length limitations will be summarily rejected. Submission is via [EasyChair](https://www.easychair.org/conferences/?conf=dtp2013). Program Committee ----------------- * Thorsten Altenkirch, University of Nottingham * Edwin Brady, University of St. Andrews * Nils Anders Danielsson, University of Gothenburg * Ranjit Jhala, UC San Diego * Conor McBride, University of Strathclyde * Brigitte Pientka, McGill University * Tim Sheard, Portland State University * Matthieu Sozeau, INRIA Paris * Aaron Stump, University of Iowa * Nikhil Swamy, Microsoft Research * Stephanie Weirich, University of Pennsylvania (chair) History ------- This workshop follows a series of workshops on dependently-typed programming. Past meetings include [DTP 2011 in Nijmegen](http://www.cs.ru.nl/dtp11/), [DTP 2010 in Edinburgh](http://sneezy.cs.nott.ac.uk/darcs/dtp10/), and [DTP 2008 in Nottingham](http://sneezy.cs.nott.ac.uk/darcs/DTP08/), as well as seminars organized in 2011 at [Shonan Village, Japan](http://www.nii.ac.jp/shonan/seminar007/) and in 2005 at [Dagstuhl, Germany](http://drops.dagstuhl.de/opus/volltexte/2005/186/). This is the first time that DTP has co-located with ICFP and has been sponsored by SIGPLAN.

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Haskell [x] and x notation - as-pattern example
by Angus Comber 04 Apr '13

04 Apr '13

I am reading Learn you a Haskell for great good and on page 40 - as-patterns. I have changed the example slightly to be: firstLetter :: String -> String firstLetter "" = "Empty string, oops" firstLetter all@(x:xs) = "The first letter of " ++ all ++ " is " ++ [x] ++ " otherbit " ++ xs Then can use like this: *Main> firstLetter "Qwerty" "The first letter of Qwerty is Q otherbit werty" But I was confused about the difference between [x] and x and why I have to use [x] in the above example. For example if I change to firstLetter :: String -> String firstLetter "" = "Empty string, oops" firstLetter all@(x:xs) = "The first letter of " ++ all ++ " is " ++ x ++ " otherbit " ++ xs I get error: Couldn't match expected type `[Char]' with actual type `Char' In the first argument of `(++)', namely `x' In the second argument of `(++)', namely `x ++ " otherbit " ++ xs' In the second argument of `(++)', namely `" is " ++ x ++ " otherbit " ++ xs' I can use xs to print "werty" but have to use [x] to print "Q". Why is that? What does [x] mean? In the (x:xs) : just delimits each element. so x is the first element. Why can I not print by using x? Also xs is of what type? list of values? So does this mean x is an element and xs must be of type list? Confused...

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Haskell Weekly News: Issue 264
by Daniel Santa Cruz 04 Apr '13

04 Apr '13

Welcome to issue 264 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week of March 17 to 30, 2013. Quotes of the Week * ddarius: (f x) is a partial application iff f x == (curry (uncurry f) x) * flebron: "Hey, I am Haskell; and this is lazy; so here's a function; I'll call it, maybe." * WinstonChurchill: It is a good thing for an uneducated man to read books of quotations. * ab9rf: (on duck typing) if you want a duck-submarine-employee-tomato, you can do that * johnw: Stealing lens from the gods, and then having my liver eaten out daily. * dibblego: scala puts road blocks in your way proportional to how effective you want to be * hiptobecubic: I want my programs to either be correct or violently explode * shachaf: edwardk will try to get you addicted to monoids. The first one is always free. * merijn: So apparently there's a footballer named lens, who played some important part in the match against the Netherlands... Which would explain the fact that twitter is telling me "lens" is trending, I was starting to think haskell had won the PL revolution with edwardk as our glorious leader ;) * elliott: all I want for christmas is a boring lambdabot. Top Reddit Stories * What’s good for C++ is good for … Haskell!? Domain: serpentine.com, Score: 101, Comments: 20 On Reddit: [1] http://goo.gl/B8Km5 Original: [2] http://goo.gl/tCB0a * Anatomy of Programming Languages (in Haskell) Domain: self.haskell, Score: 72, Comments: 29 On Reddit: [3] http://goo.gl/YmO5M Original: [4] http://goo.gl/YmO5M * Programming and Reasoning with Algebraic Effects and Dependent Types Domain: edwinb.wordpress.com, Score: 58, Comments: 28 On Reddit: [5] http://goo.gl/xfH0Z Original: [6] http://goo.gl/AdGEJ * School of Haskell—Basic Lensing Domain: fpcomplete.com, Score: 57, Comments: 39 On Reddit: [7] http://goo.gl/JIowk Original: [8] http://goo.gl/NX1ak * Haskell for all: mmorph-1.0.0: Monad morphisms Domain: haskellforall.com, Score: 56, Comments: 18 On Reddit: [9] http://goo.gl/nlHfN Original: [10] http://goo.gl/6aHZt * Haskell News Domain: haskellnews.org, Score: 43, Comments: 12 On Reddit: [11] http://goo.gl/fNzzI Original: [12] http://goo.gl/4K1tD * pipes-3.2: ListT, Codensity, ArrowChoice, and performance Domain: haskellforall.com, Score: 43, Comments: 19 On Reddit: [13] http://goo.gl/a0xm8 Original: [14] http://goo.gl/RFLdw * Introducing diagrams-haddock Domain: byorgey.wordpress.com, Score: 41, Comments: 13 On Reddit: [15] http://goo.gl/d5Vl5 Original: [16] http://goo.gl/PmUFs * Optimising Purely Functional GPU Programs Domain: justtesting.org, Score: 41, Comments: 2 On Reddit: [17] http://goo.gl/ZgiXt Original: [18] http://goo.gl/M5fop * Creating board games in Haskell in 100 lines of code Domain: keera.co.uk, Score: 38, Comments: 30 On Reddit: [19] http://goo.gl/lbZke Original: [20] http://goo.gl/epwqQ * What is the logarithm or root operation in type-space? (x-post from r/compsci) Domain: cstheory.stackexchange.com, Score: 38, Comments: 17 On Reddit: [21] http://goo.gl/1z3a9 Original: [22] http://goo.gl/JXAlC * New GHC Extension - Nullary Type Classes (apparently not an April Fool's joke) Domain: hackage.haskell.org, Score: 37, Comments: 24 On Reddit: [23] http://goo.gl/rD5KC Original: [24] http://goo.gl/drfb7 * The Monad.Reader issue 21 Domain: themonadreader.files.wordpress.com, Score: 30, Comments: 2 On Reddit: [25] http://goo.gl/R1dke Original: [26] http://goo.gl/nGHjP * Dependently Typed Functional Programming with Idris 4 (last lecture) Domain: vimeo.com, Score: 28, Comments: 4 On Reddit: [27] http://goo.gl/ozbtK Original: [28] http://goo.gl/2xsaB * Conal Elliot: Folds and Unfolds Domain: conal.net, Score: 28, Comments: 5 On Reddit: [29] http://goo.gl/ZzFZ1 Original: [30] http://goo.gl/JVQK4 * Mihai-Radu Popescu's book in progress: "Speeding Through Haskell" Domain: sthaskell.com, Score: 26, Comments: 15 On Reddit: [31] http://goo.gl/d1wZF Original: [32] http://goo.gl/oB0e8 * hchip - a Haskell emulator for Chip16 Domain: self.haskell, Score: 25, Comments: 1 On Reddit: [33] http://goo.gl/mtHhg Original: [34] http://goo.gl/mtHhg * Introduction to Haskell, Lecture 8 is Live (Monads) Domain: shuklan.com, Score: 25, Comments: 22 On Reddit: [35] http://goo.gl/nCV1q Original: [36] http://goo.gl/D4VGn * School of Haskell: Learning Haskell Through Koans Domain: fpcomplete.com, Score: 22, Comments: 2 On Reddit: [37] http://goo.gl/sKxmz Original: [38] http://goo.gl/2n9aF * Arrow Notation in Functional Reactive Programming demonstrated with a simple OpenGL demo (Yampa) Domain: youtube.com, Score: 22, Comments: 9 On Reddit: [39] http://goo.gl/NN8nr Original: [40] http://goo.gl/m5XEb Top StackOverflow Questions * Maintaining complex state in Haskell votes: 23, answers: 1 Read on SO: [41] http://goo.gl/XbFtx * Is using mapM/sequence considered good practice? votes: 14, answers: 3 Read on SO: [42] http://goo.gl/juA3q * Can I model a list of successes with short circuiting failure via the composition of applicative functors? votes: 12, answers: 2 Read on SO: [43] http://goo.gl/biKxw * Understanding Polytypes in Hindley-Milner Type Inference votes: 12, answers: 2 Read on SO: [44] http://goo.gl/sjzJJ * Why add “Eq” type constraint without using “==”? votes: 11, answers: 1 Read on SO: [45] http://goo.gl/hljhA * :: a -> (a -> b) -> b operator (Haskell) votes: 11, answers: 3 Read on SO: [46] http://goo.gl/O643o * What's the most efficient way to represent finite (non-recursive) algebraic type values? votes: 10, answers: 2 Read on SO: [47] http://goo.gl/ikN78 * What's the “easier way” that deprecates the need for Data.Conduit.Util's zip? votes: 10, answers: 1 Read on SO: [48] http://goo.gl/kk6jq * Haskell equivalent of scala collect votes: 10, answers: 1 Read on SO: [49] http://goo.gl/wjKTR * Scheduling a Timeout in Haskell votes: 10, answers: 1 Read on SO: [50] http://goo.gl/Pya8z Until next time, +Daniel Santa Cruz References 1. http://www.serpentine.com/blog/2013/03/20/whats-good-for-c-is-good-for-hask… 2. http://www.reddit.com/r/haskell/comments/1aok5k/whats_good_for_c_is_good_fo… 3. http://www.reddit.com/r/haskell/comments/1b4m75/anatomy_of_programming_lang… 4. http://www.reddit.com/r/haskell/comments/1b4m75/anatomy_of_programming_lang… 5. https://edwinb.wordpress.com/2013/03/28/programming-and-reasoning-with-alge… 6. http://www.reddit.com/r/haskell/comments/1b64xh/programming_and_reasoning_w… 7. https://www.fpcomplete.com/user/tel/basic-lensing 8. http://www.reddit.com/r/haskell/comments/1anf0n/school_of_haskellbasic_lens… 9. http://www.haskellforall.com/2013/03/mmorph-100-monad-morphisms.html 10. http://www.reddit.com/r/haskell/comments/1ahyzu/haskell_for_all_mmorph100_m… 11. http://haskellnews.org/ 12. http://www.reddit.com/r/haskell/comments/1ahgrn/haskell_news/ 13. http://www.haskellforall.com/2013/03/pipes-32-listt-codensity-arrowchoice.h… 14. http://www.reddit.com/r/haskell/comments/1av2gi/pipes32_listt_codensity_arr… 15. http://byorgey.wordpress.com/2013/03/23/introducing-diagrams-haddock/ 16. http://www.reddit.com/r/haskell/comments/1aw33e/introducing_diagramshaddock/ 17. http://justtesting.org/optimising-purely-functional-gpu-programs 18. http://www.reddit.com/r/haskell/comments/1bapa5/optimising_purely_functiona… 19. http://keera.co.uk/blog/2013/03/19/creating-board-games-in-haskell/ 20. http://www.reddit.com/r/haskell/comments/1ani3n/creating_board_games_in_has… 21. http://cstheory.stackexchange.com/questions/17006/what-is-the-logarithm-or-… 22. http://www.reddit.com/r/haskell/comments/1aynxj/what_is_the_logarithm_or_ro… 23. http://hackage.haskell.org/trac/ghc/ticket/7642 24. http://www.reddit.com/r/haskell/comments/1atlvu/new_ghc_extension_nullary_t… 25. http://themonadreader.files.wordpress.com/2013/03/issue21.pdf 26. http://www.reddit.com/r/haskell/comments/1ahrii/the_monadreader_issue_21/ 27. http://vimeo.com/62059837 28. http://www.reddit.com/r/haskell/comments/1aisv0/dependently_typed_functiona… 29. http://conal.net/talks/folds-and-unfolds.pdf 30. http://www.reddit.com/r/haskell/comments/1asxuf/conal_elliot_folds_and_unfo… 31. http://www.sthaskell.com/ 32. http://www.reddit.com/r/haskell/comments/1azvcy/mihairadu_popescus_book_in_… 33. http://www.reddit.com/r/haskell/comments/1akhgi/hchip_a_haskell_emulator_fo… 34. http://www.reddit.com/r/haskell/comments/1akhgi/hchip_a_haskell_emulator_fo… 35. http://shuklan.com/haskell/lec09.html 36. http://www.reddit.com/r/haskell/comments/1alqjq/introduction_to_haskell_lec… 37. https://www.fpcomplete.com/blog/2013/03/learning-through-koans 38. http://www.reddit.com/r/haskell/comments/1amuuz/school_of_haskell_learning_… 39. http://www.youtube.com/watch?v=T3xXebIr8AM#t=17m58s 40. http://www.reddit.com/r/haskell/comments/1ao4nx/arrow_notation_in_functiona… 41. http://stackoverflow.com/questions/15467925/maintaining-complex-state-in-ha… 42. http://stackoverflow.com/questions/15546216/is-using-mapm-sequence-consider… 43. http://stackoverflow.com/questions/15460794/can-i-model-a-list-of-successes… 44. http://stackoverflow.com/questions/15497315/understanding-polytypes-in-hind… 45. http://stackoverflow.com/questions/15512541/why-add-eq-type-constraint-with… 46. http://stackoverflow.com/questions/15604290/a-a-b-b-operator-haskell 47. http://stackoverflow.com/questions/15572996/whats-the-most-efficient-way-to… 48. http://stackoverflow.com/questions/15627359/whats-the-easier-way-that-depre… 49. http://stackoverflow.com/questions/15634549/haskell-equivalent-of-scala-col… 50. http://stackoverflow.com/questions/15671328/scheduling-a-timeout-in-haskell 51. https://plus.google.com/105107667630152149014/about

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ANN: adobe-swatch-exchange-0.1.0.0
by Jeremy Shaw 03 Apr '13

03 Apr '13

I am pleased to annouce the release of adobe-swatch-exchange 0.1.0.0. My primary motivation in writing this is to make it easier to download color swatches from http://kuler.adobe.com/ and test them on my site. Though, perhaps there is already a great way of doing this and I didn't look hard enough. But, the end result is we can now read and write .ASE files in Haskell and convert them to .css. So that probably opens up some new possibilities. I have provided both a library and an executable. I have also used this as a way to test the waters with github, https://github.com/stepcut/ase2css I heard putting things on github will get me all sorts of contributors. I suggest someone start with haddock comments. ;) Cheers! - jeremy

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Haskell 2013 call for submissions
by Chung-chieh Shan 02 Apr '13

02 Apr '13

=================================================================== ACM SIGPLAN HASKELL SYMPOSIUM 2013 CALL FOR SUBMISSIONS Boston, MA, USA, 23-24 September 2013, directly before ICFP http://www.haskell.org/haskell-symposium/2013/ haskell2013(a)easychair.org =================================================================== The ACM SIGPLAN Haskell Symposium 2013 will be colocated with the 2013 International Conference on Functional Programming (ICFP) in Boston, MA, USA. This year, the symposium will last 2 days rather than 1 as in the past. Thanks to broader participation from a growing community, we will be able to include more regular papers as well as system demonstrations and a new category of panel discussions, while upholding the scientific quality of the symposium. The Haskell Symposium seeks to present original research on Haskell, to discuss practical experience and future development of the language, as well as to promote other forms of denotative programming. Topics of interest include * Language Design, with a focus on possible extensions and modifications of Haskell as well as critical discussions of the status quo; * Theory, such as formal semantics of the present language or future extensions, type systems, effects, metatheory, and foundations for program analysis and transformation; * Implementations, including program analysis and transformation, static and dynamic compilation for sequential, parallel, and distributed architectures, memory management, as well as foreign function and component interfaces; * Tools, such as profilers, tracers, debuggers, preprocessors, and testing tools; * Applications, to scientific and symbolic computing, databases, multimedia, telecommunication, the web, and so forth; * Functional Pearls, being elegant and instructive programming examples; * Experience Reports, to document general practice and experience in education, industry, or other contexts. Papers in the latter three categories need not necessarily report original research results. They may report instead, for example, reusable programming idioms, elegant ways to approach a problem, or practical experience that will be useful to other users, implementors, or researchers. (Links with more advice appear on the symposium web page.) The key criterion for such a paper is that it makes a contribution from which other Haskellers can benefit. It is not enough simply to describe a program! Regular papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work (also for other languages where appropriate). In addition, we solicit proposals for * System Demonstrations (no longer than a regular paper talk), based on running (perhaps prototype) software rather than necessarily on novel research results. * Panel Discussions (no shorter than a regular paper talk), submitted by a moderator who proposes to bring together specific panelists who have agreed to address a specific pressing issue in the Haskell community. Panels will subsume past "Future of Haskell" discussions. These proposals should summarize the system capabilities that would be demonstrated or the panelist positions that would be discussed. The proposals should explain (and will be judged on) whether the ensuing session is likely to be important and interesting to the Haskell community at large, whether on grounds academic or industrial, theoretical or practical, technical or social. Please contact the program chair with any questions about the relevance of a proposal. Travel Support: =============== Student attendees with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses. PAC also offers other support, such as for child-care expenses during the meeting or for travel costs for companions of SIGPLAN members with physical disabilities, as well as for travel from locations outside of North America and Europe. For details on the PAC programme, see its web page (http://www.sigplan.org/PAC.htm) Proceedings: ============ There will be formal proceedings published by ACM Press. Accepted papers will be included in the ACM Digital Library. Authors must transfer copyright to ACM upon acceptance (for government work, to the extent transferable), but retain various rights (http://www.acm.org/publications/policies/copyright_policy) Authors are encouraged to publish auxiliary material with their paper (source code, test data, etc.); they retain copyright of auxiliary material. Accepted demo and panel proposals will be posted on the symposium web page, but not formally published in the proceedings. Submission Details: =================== * Abstract submission: Wed 12th June 2013, anywhere on earth * Paper submission : Fri 14th June 2013, anywhere on earth * Demo submission : Fri 14th June 2013, anywhere on earth (prior abstract submission unnecessary) * Panel submission : Fri 28th June 2013, anywhere on earth (prior abstract submission unnecessary) * Author notification: Thu 11th July 2013 * Final papers due : Thu 25th July 2013 Submitted papers should be in portable document format (PDF), formatted using the ACM SIGPLAN style guidelines (http://www.acm.org/sigs/sigplan/authorInformation.htm) The text should be in a 9-point font in two columns. The length is restricted to 12 pages, except for "Experience Report" papers, which are restricted to 6 pages. Papers need not fill the page limit -- for example, a Functional Pearl may be much shorter than 12 pages. Each paper submission must adhere to SIGPLAN's republication policy, as explained on the web. Demo and panel proposals are limited to 2-page abstracts, in the same ACM format as papers. "Functional Pearls", "Experience Reports", "Demo Proposals", and "Panel Proposals" should be marked as such with those words in the title at time of submission. The paper submission deadline and length limitations are firm. There will be no extensions, and papers violating the length limitations will be summarily rejected. Submission is via EasyChair: https://www.easychair.org/conferences/?conf=haskell2013 Programme Committee: ==================== * Andreas Abel, Ludwig-Maximilians-Universität München * Lennart Augustsson, Standard Chartered Bank * Jean-Philippe Bernardy, Chalmers University of Technology * Olaf Chitil, University of Kent * Neil Ghani, University of Strathclyde * Hans-Wolfgang Loidl, Heriot-Watt University * Ian Lynagh, Well-Typed LLP * David Mazières, Stanford University * Akimasa Morihata, Tohoku University * Takayuki Muranushi, Kyoto University * Keiko Nakata, Tallinn University of Technology * Alberto Pardo, Universidad de la República * Norman Ramsey, Tufts University * Neil Sculthorpe, University of Kansas * Chung-chieh Shan (chair), Indiana University * Christina Unger, Universität Bielefeld * Dana N. Xu, INRIA

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