- Haskell-Cafe - Haskell.org

IDE-backend + Atom editor
by JP Moresmau 14 May '15

14 May '15

Hello, when the open sourcing of IDE-backend was announced ( https://www.fpcomplete.com/blog/2015/03/announce-ide-backend) one thing mentioned was Atom support, and indeed the home page for the client ( https://github.com/chrisdone/ide-backend-client) mentions Atom. But is there a project out there I can use that brings the two together? The ide-haskell (https://atom.io/packages/ide-haskell) Atom plugin still relies on ghc-mod as far as I can tell. I saw edsko tutorial on writing Atom plugin in Haskell ( http://edsko.net/2015/02/14/atom-haskell/) so it seem we are tentalizingly close to have Atom + Haskell implemented in Haskell, and I'd like to give it a go if there's anything available out there (and maybe help if needed). Thanks! JP -- JP Moresmau http://jpmoresmau.blogspot.com/

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CFP: Extended Deadline: Functional High-Performance Computing (held with ICFP)
by Geoffrey Mainland 14 May '15

14 May '15

====================================================================== CALL FOR PAPERS FHPC 2015 The 4th ACM SIGPLAN Workshop on Functional High-Performance Computing Vancouver, British Columbia, Canada, Canada September 3, 2015 https://sites.google.com/site/fhpcworkshops/ Co-located with the International Conference on Functional Programming (ICFP 2015) EXTENDED Submission Deadline: Friday, 22 May, 2015 (anywhere on earth) ====================================================================== The FHPC workshop aims at bringing together researchers exploring uses of functional (or more generally, declarative or high-level) programming technology in application domains where high performance is essential. The aim of the meeting is to enable sharing of results, experiences, and novel ideas about how high-level, declarative specifications of computationally challenging problems can serve as maintainable and portable code that approaches (or even exceeds) the performance of machine-oriented imperative implementations. All aspects of performance critical programming and parallel programming are in-scope for the workshop, irrespective of hardware target. This includes both traditional large-scale scientific computing (HPC), as well as work targeting single node systems with SMPs, GPUs, FPGAs, or embedded processors. It is becoming apparent that radically new and well founded methodologies for programming such systems are required to address their inherent complexity and to reconcile execution performance with programming productivity. Proceedings: ============ Accepted papers will be published by the ACM and will appear in the ACM Digital Library. * Submissions due: Friday, 22 May, 2015 (anywhere on earth) * Author notification: Friday, 26 June, 2015 * Final copy due: Sunday, 19 July, 2015 Submitted papers must be in portable document format (PDF), formatted according to the ACM SIGPLAN style guidelines (2 column, 9pt format). See http://www.sigplan.org/authorInformation.htm for more information and style files. Typical papers are expected to be 8 pages (but up to four additional pages are permitted). Contributions to FHPC 2015 should be submitted via Easychair, at the following URL: * https://www.easychair.org/conferences/?conf=fhpc15 The submission site is now open. The FHPC workshops adhere to the ACM SIGPLAN policies regarding programme committee contributions and republication. Any paper submitted must adhere to ACM SIGPLAN's republication policy. PC member submissions are welcome, but will be reviewed to a higher standard. http://www.sigplan.org/Resources/Policies/Review http://www.sigplan.org/Resources/Policies/Republication 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) Programme Committee: ==================== Tiark Rompf (co-chair), Purdue University, USA Geoffrey Mainland (co-chair), Drexel University, USA Kevin Brown Stanford University, USA James Cheney University of Edinburgh, UK Albert Cohen INRIA, France David Duke University of Leeds, UK Yukiyoshi Kameyama University of Tsukuba, Japan Gabriele Keller University of New South Wales, Australia Paul H J Kelly Imperial College London, UK Trevor L. Mcdonell Indiana University, USA Greg Michaelson Heriot-Watt University, UK Cosmin E. Oancea University of Copenhagen, Denmark Markus Pueschel ETH Zurich, Switzerland Sukyoung Ryu KAIST, Korea Alexander Slesarenko Huawei, Russia Josef Svenningsson Chalmers University of Technology, Sweden

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all for Contributions - Haskell Communities and Activities Report, May 2015 edition (28th edition)
by Mihai Maruseac 13 May '15

13 May '15

Dear all, We would like to collect contributions for the 28th edition of the ============================================================ Haskell Communities & Activities Report http://www.haskell.org/haskellwiki/Haskell_Communities_and_Activities_Report Submission deadline: 17 May 2015 (please send your contributions to hcar at haskell.org, in plain text or LaTeX format) ============================================================ This is the short story (one extra point to the story added from previous editions): * 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 us, so that we can contact the project leaders and ask them to submit an entry. * **NEW**: If you are working on a project that is looking for contributors, please write a short entry and submit it, mentioning that your are looking for contributors. The final report might have an index with such projects, provided we get enough such submissions. * 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, Mihai Maruseac and Alejandro Serrano Mena 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/05-2015/template.tex There is also a LaTeX style file at http://haskell.org/communities/05-2015/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 soon receive your old entry as a template (provided we 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://www.andres-loeh.de/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 or .png format, then, PNG being preferred for simplicity. 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 simply ask us. 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. You can use HCAR to ask for more contributors to your project, it is a good way to gain visibility and traction. Q: If I do not update my entry, but want to keep it in the report, what should I do? A: Tell us 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 its destination, and not ended up in a spam folder? A: Prior to publication of the final report, we will send a draft to all contributors, for possible corrections. So if you do not hear from us within two weeks after the deadline, it is safer to send another mail and check whether your first one was received. -- Mihai Maruseac (MM) "If you don't know, the thing to do is not to get scared, but to learn." -- Atlas Shrugged.

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Job openings for Haskell, O'Caml programmers at Swedish spin-off startup
by Johan Glimming 13 May '15

13 May '15

Hi Haskell people, and beyond, Summary: Openings for software developers <https://goo.gl/vdu1d4> highly trained in functional programming, six developer or more entangled in our "teams", three with considerable Haskell, O'Caml experience, talents, entrepreneurial mind-set, and three for Scala, spear-edge Functor Consulting branch, with out-standing industrial track-records, as the new constructive programming paradigm is gradually unleashed to the software industry from Functor Group AB, Sweden. Keywords: type theory, dependent type, new programming paradigm, static analysis with dependent types, DDD-like development with solid Scandinavian-style Martin-Löf type theory operational semantics in the VM above LLVM, Haskell, O’Caml, embedded systems is one submarket. Official call with the details here: https://goo.gl/vdu1d4 <https://goo.gl/vdu1d4> <https://goo.gl/vdu1d4> We will always work closely with academia and internships, MSc theses and research collaborations are always interesting though right now we are focused on delivering to customers and building up the business meaning larger research projects are not yet possible, a large-scale EU project planned but not for this year. You’re most welcome to apply via jobs(a)functor.se <mailto:jobs@functor.se>. See the call for details! Yours Sincerely, Johan Glimming — Dr Johan Glimming Chief Technical Officer and Co-Founder at Functor AB and Functor Group AB LinkedIn profile: www.linkedin.com/in/glimming <http://www.linkedin.com/in/glimming> Mobile: +46-76-7646000 (direct) Main: +46-8-55005500 Functor AB, Box 7070, 164 07 Kista, SWEDEN Web: www.functorgroup.com <http://www.functorgroup.com/> Twitter: @functors <https://www.twitter.com/functors/>

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Start GHCI with a static library
by aditya siram 13 May '15

13 May '15

Hi all, I have a Haskell library I'd like to load up in GHCI along with a statically linked C library (libblah.a) . Is there any way to do this? My Googling only turns up instructions on loading a shared library (libblah.so). Thanks! -deech

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Is this functional reactive programming
by Clinton Mead 12 May '15

12 May '15

What I want to be able to do is something like this: do x <- newSTRef 2 y <- newSTRef 3 z <- letSTRef (x + y) r1 <- readSTRef z writeSTRef x 5 r2 <- readSTRef z return (r1, r2) This should return (6,15) The "letSTRef" is what's new. The value it returns can change based on the parts that make up it's function changing. I understand this syntax above isn't going to work (I'd have to use applicative at least I'd imagine) but my main question is that does something like this exist? Is it functional reactive programming or is it something else? I don't want to be reinventing the wheel if this type of idea is already implemented but I haven't recognised it.

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Call for participation: Applied Functional Programming (AFP) Summerschool 6-17 July 2015, Utrecht, Netherlands
by Atze Dijkstra 12 May '15

12 May '15

=========== AFP Summerschool 2015 =========== Applied Functional Programming (AFP) Summerschool July 6-17, 2015 Utrecht University, Department of Information and Computing Sciences Utrecht, The Netherlands Summerschool & registration website: http://www.utrechtsummerschool.nl/courses/science/applied-functional-progra… AFP website : http://www.cs.uu.nl/wiki/USCS contact : Uscs-afp(a)lists.science.uu.nl *** The 2015 edition of the Applied Functional Programming (AFP) Summerschool in Utrecht, Netherlands will be held from 6-17 July 2015. The summerschool teaches Haskell on both beginners and advanced levels via lectures and lab exercises. More info can be found via the references above, included here is a summary from the summerschool info: ``Typed functional programming in Haskell allows for the development of compact programs in minimal time and with maximal guarantees about robustness and correctness. The course introduces Haskell as well as its theoretical underpinnings such as typed lambda calculus, and Damas-Milner type inference. There is ample opportunity to put this all in practice during lab sessions. Typed functional programming languages allow for the development of robust, concise programs in a short amount of time. The key advantages are higher-order functions as an abstraction mechanism, and an advanced type system for safety and reusability. This course introduces Haskell, a state-of-the-art functional programming language, together with some of its theoretical background, such as typed lambda calculi, referential transparency, Damas-Milner type inference, type level programming, and functional design patterns. We will combine this with applications of functional programming, concentrating on topics such as language processing, building graphical user interfaces, networking, databases, and programming for the web. The goal of the course is not just to teach the programming language and underlying theory, but also to learn about the Haskell community and to get hands-on experience by doing lab exercises or a Haskell project of your own.'' *** This year is somewhat special in that the Tour de France starts in Utrecht the weekend before the start of the summerschool. It is an opportunity for enjoying the related festivities. It also implies that housing may be more difficult the weekend before the summerschool, something to keep in mind when you wait with registration until the latest. regards, - Atze - Atze Dijkstra, Department of Information and Computing Sciences. /|\ Utrecht University, PO Box 80089, 3508 TB Utrecht, Netherlands. / | \ Tel.: +31-30-2534118/1454 | WWW : http://www.cs.uu.nl/~atze . /--| \ Fax : +31-30-2513971 .... | Email: atze(a)uu.nl ............... / |___\ _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

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Multiway tree vs rose tree
by Tara Athan 12 May '15

12 May '15

Hi - I am new to this list, and the only archive I could find is the Mailman archive, which is next to impossible to search. So this may be a topic that has been previously discussed, I don't know... The documentation at https://hackage.haskell.org/package/containers-0.3.0.0/docs/Data-Tree.html says that a rose tree is another name for multiway tree. But this is not true according to my understanding of the accepted definition in the CS literature (see e.g. http://doc.utwente.nl/66626/1/db-utwente-0000003528.pdf) Rose trees do not have labels at the nodes, only at the leaves (aka tips). There is another page https://wiki.haskell.org/Algebraic_data_type#Rose_tree that also uses this divergent definition. To further propagate this problem, the Wikipedia page https://en.wikipedia.org/wiki/Rose_tree uses these Haskell wiki pages as the definitive source. Tara

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3rd CFP FARM 2015 -- final reminder
by Anton Kholomiov 12 May '15

12 May '15

************************************************************ 3rd CFP FARM 2015 3rd ACM SIGPLAN International Workshop on Functional Art, Music, Modelling and Design Vancouver, Canada, 5 September, 2015 affiliated with ICFP 2015 Full Paper and Demo Abstract submission Deadline: 17 May ************************************************************ The ACM SIGPLAN International Workshop on Functional Art, Music, Modelling and Design (FARM) gathers together people who are harnessing functional techniques in the pursuit of creativity and expression. Functional Programming has emerged as a mainstream software development paradigm, and its artistic and creative use is booming. A growing number of software toolkits, frameworks and environments for art, music and design now employ functional programming languages and techniques. FARM is a forum for exploration and critical evaluation of these developments, for example to consider potential benefits of greater consistency, tersity, and closer mapping to a problem domain. FARM encourages submissions from across art, craft and design, including textiles, visual art, music, 3D sculpture, animation, GUIs, video games, 3D printing and architectural models, choreography, poetry, and even VLSI layouts, GPU configurations, or mechanical engineering designs. The language used need not be purely functional (“mostly functional” is fine), and may be manifested as a domain specific language or tool. Theoretical foundations, language design, implementation issues, and applications in industry or the arts are all within the scope of the workshop. Submissions are invited in two categories: * Full papers 5 to 12 pages using the ACM SIGPLAN template. FARM 2015 is an interdisciplinary conference, so a wide range of approaches are encouraged and we recognize that the appropriate length of a paper may vary considerably depending on the approach. However, all submissions must propose an original contribution to the FARM theme, cite relevant previous work, and apply appropriate research methods. * Demo abstracts Demo abstracts should describe the demonstration and its context, connecting it with the themes of FARM. A demo could be in the form of a short (10-20 minute) tutorial, presentation of work-in-progress, an exhibition of some work, or even a performance. Abstracts should be no longer than 2 pages, using the ACM SIGPLAN template and will be subject to a light-touch peer review. If you have any questions about what type of contributions that might be suitable, or anything else regarding submission or the workshop itself, please contact the organisers at: farm-2015(a)easychair.org KEY DATES: Full Paper and Demo Abstract submission Deadline: 17 May Author Notification: 26 June Camera Ready: 19 July Workshop: 5 September SUBMISSION All papers and demo abstracts must be in portable document format (PDF), using the ACM SIGPLAN style guidelines. The text should be in a 9-point font in two columns. The submission itself will be via EasyChair: https://easychair.org/conferences/?conf=farm2015 PUBLICATION Accepted papers will be included in the formal proceedings published by ACM Press and will also be made available through the the ACM Digital Library; see http://authors.acm.org/main.cfm for information on the options available to authors. Authors are encouraged to submit auxiliary material for publication along with their paper (source code, data, videos, images, etc.); authors retain all rights to the auxiliary material. WORKSHOP ORGANISATION Workshop Chair: Henrik Nilsson, University of Nottingham Program Chair: David Janin, University of Bordeaux Publicity Chair: Samuel Aaron, University of Cambridge Program Committee: Samuel Aaron, University of Cambridge Jean Bresson, IRCAM Paris David Broman, KTH and UC Berkeley David Janin (chair), University of Bordeaux Anton Kholomiov, Orffeus instrumental ensemble Moscow Alex Mclean, University of Leeds Carin Meier, Outpace Systems Henrik Nilsson, University of Nottingham Yann Orlarey, GRAME Lyon Donya Quick, Yale University Shigeki Sagayama, Meiji University Chung-chieh Shan, Indiana University Michael Sperber, Active Group GmbH Bodil Stokke, FutureAdLabs For further details, see the FARM website: http://functional-art.org

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ANN: codec: easy bidirectional serialization and first-class record construction
by Patrick Chilton 12 May '15

12 May '15

Tired of writing complementary parseJSON/toJSON, peek/poke or Binary get/put functions? codec <https://github.com/chpatrick/codec> provides easy bidirectional serialization of plain Haskell records in any Applicative context. All you need to do is provide a de/serializer for every record field in any order you like, and you get a de/serializer for the whole structure. The type system ensures that you provide every record exactly once. It also includes a library for general record construction in an Applicative context, of which creating codecs is just one application. *JSON:* data User = User { username :: Text , userEmail :: Text , userLanguages :: [ Text ] , userReferrer :: Maybe User } deriving Show genFields ''User userCodec :: JSONCodec User userCodec = obj "user object" $ User $>> f_username >-< "user" >>> f_userEmail >-< "email" >>> f_userLanguages >-< "languages" >>> f_userReferrer >-< opt "referrer" instance FromJSON User where parseJSON = parseVal userCodec instance ToJSON User where toJSON = produceVal userCodec *Bit fields:* ipv4Codec :: BinaryCodec IPv4 ipv4Codec = toBytes $ IPv4 $>> f_version >-< word8 4 >>> f_ihl >-< word8 4 >>> f_dscp >-< word8 6 >>> f_ecn >-< word8 2 >>> f_totalLength >-< word16be 16 >>> f_identification >-< word16be 16 >>> f_flags >-< word8 3 >>> f_fragmentOffset >-< word16be 13 >>> f_timeToLive >-< word8 8 >>> f_protocol >-< word8 8 >>> f_headerChecksum >-< word16be 16 >>> f_sourceIP >-< word32be 32 >>> f_destIP >-< word32be 32 instance Binary IPv4 where get = parse ipv4Codec put = produce ipv4Codec The same types and combinators can be used to make Storable or Binary instances, or used with pretty much any de/serialization library. The implementation only uses a little bit of Template Haskell to generate the f_... structures for each field and the rest is very basic in terms of extensions (no DataKinds or type families needed). Please take a look at the docs and the examples. I'd love to get some feedback before I put it on Hackage. :) All the best, Patrick

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