February 2012 - Haskell

ANN: hledger 0.17
by Simon Michael 02 Feb '12

02 Feb '12

Happy new year all. hledger and hledger-web 0.17 are released. Not quite as planned, this release mainly fixes bugs and updates dependencies. Also the hledger-vty and hledger-chart packages have been demoted to "unmaintained extras" for now to save time. hledger is a library, command-line tool, and web app for reporting on financial transactions stored in a text file. It is a haskell port and friendly fork of John Wiegley's Ledger. Home: http://hledger.org To install: cabal update, then cabal install hledger (or cabal-install hledger-web). If you have any trouble, please let me know, or watch the mail list/bug tracker for updates. (Ready to run binaries are provided on request to project donors, a great way to support the project - see http://hledger.org/DOWNLOAD.html.) Release notes for 0.17: * support HP 2011.4.0.0 * support and require cmdargs 0.9 * allow non-threaded builds, supporting more debian architectures * parsing: give a clearer error when journal file path contains ~ * parsing: -B/--cost now ignores P historical prices, like ledger * parsing: inferred amounts now use the cost commodity if known, like ledger (#69) * balance: report differently-priced lots in an account as a single amount, like ledger * web: support and require yesod >= 0.9.4 * web: use the main aeson package again * web: fix a regression with dollar signs in hamlet templates * web: add form allowed blank account names (#81) * chart, vty: hledger-chart and hledger-vty demoted to non-maintained extras for now Best, -Simon

1 0

Haskell Weekly News: Issue 213
by Daniel Santa Cruz 02 Feb '12

02 Feb '12

Welcome to issue 213 of the HWN, a newsletter covering quotes, stories, and questions seen around the net concerning Haskell during the week of January 22 to 28, 2012. You can read the HTML version at: http://contemplatecode.blogspot.com/2012/02/haskell-weekly-news-issue-213.h… Quotes of the Week * monochrom: great way to answer a semantics question by commenting on the font ... "what is the semantics of IO?" "the I may be narrower than O in some fonts, and same width in some other fonts" ... "on very old typewriters, it also denotes the number 10 (ten), for those of you looking for a denotation" * elliott: |\/|/-\|-|-|=|\||} is my preferred mappend operator * merijn: rostayob: I used to be a functional programmer like you, but then I took an UML diagram to the knee >.> * mauke: monoids are simple elliott: And as we all know, monads are basically just monoids! monochrom: haskell is basically just ascii * O'Keefe: "Elegance is not optional." * O'Keefe: "If I don't write it, I won't wrong it." * kmc: "monads are like containers, as long as you forget everything you know about containers, and treat it as a synonym for 'monad'" * Enigmagic: this calls for mfix and some tequila Top Reddit Stories * SPJ : Escape From the Ivory Tower: The Haskell Journey, From 1990 to 2011 Domain: yow.eventer.com, Score: 67, Comments: 12 On Reddit: [1] http://goo.gl/JqRUW Original: [2] http://goo.gl/9ILW1 * Make Things Now! - Pragmatic FP With Haskell (slides) Domain: code.haskell.org, Score: 44, Comments: 22 On Reddit: [3] http://goo.gl/WJQnH Original: [4] http://goo.gl/UMd9y * ANNOUNCE: GHC 7.4.1 Release Candidate 2 Domain: haskell.org, Score: 37, Comments: On Reddit: [5] http://goo.gl/D9F37 Original: [6] http://goo.gl/sdD1L * Web application that uses UHC to compile Haskell to JavaScript Domain: alessandrovermeulen.me, Score: 36, Comments: 13 On Reddit: [7] http://goo.gl/A3S0k Original: [8] http://goo.gl/lyX2K * Web app that shows you the changes between releases of packages on hackage Domain: hdiff.luite.com, Score: 33, Comments: 4 On Reddit: [9] http://goo.gl/6ioFh Original: [10] http://goo.gl/aZAyc * Combining Regions and Iteratees Domain: haskell.org, Score: 30, Comments: 10 On Reddit: [11] http://goo.gl/LEPiQ Original: [12] http://goo.gl/k3wpd * MonadBaseControl is unsound : Inside 233 Domain: blog.ezyang.com, Score: 29, Comments: 19 On Reddit: [13] http://goo.gl/ptCF6 Original: [14] http://goo.gl/Y5bbh * Yesod example: wiki, markdown, chat subsite, event source Domain: yesodweb.com, Score: 29, Comments: 1 On Reddit: [15] http://goo.gl/GyfzS Original: [16] http://goo.gl/on96C * inner beauty of tree traversals: pre- and post-order Domain: blog.moertel.com, Score: 29, Comments: On Reddit: [17] http://goo.gl/6fKzq Original: [18] http://goo.gl/NpjrO * Seem like there's a boycott of Elsevier going on. Domain: thecostofknowledge.com, Score: 29, Comments: 1 On Reddit: [19] http://goo.gl/2B106 Original: [20] http://goo.gl/dvxML * Unifying Monoids and Monads with Polymorphic Kinds Domain: jonmsterling.com, Score: 26, Comments: 29 On Reddit: [21] http://goo.gl/kTafx Original: [22] http://goo.gl/A3IrU * Modelling IO: MonadIO and beyond Domain: blog.ezyang.com, Score: 26, Comments: 4 On Reddit: [23] http://goo.gl/gr2M1 Original: [24] http://goo.gl/0n1a9 Top StackOverflow Questions * Is it a good idea to compile a language to C? votes: 26, answers: 7 Read on SO: [25] http://goo.gl/V8sSx * Haskell GHC: what is the time complexity of a pattern match with N constructors? votes: 19, answers: 1 Read on SO: [26] http://goo.gl/SU0l8 * What to use instead of a main loop in Haskell? votes: 12, answers: 2 Read on SO: [27] http://goo.gl/iYasz * Associated types and container elements votes: 12, answers: 2 Read on SO: [28] http://goo.gl/zBNWU * Undefined at the type level votes: 12, answers: 1 Read on SO: [29] http://goo.gl/m9Acn * Is there a good reason why `deleteBy` does not have its most general type? votes: 10, answers: 3 Read on SO: [30] http://goo.gl/dQDrf * Using low bitsize integral types like `Int8` and what they are for votes: 9, answers: 2 Read on SO: [31] http://goo.gl/YaE68 * How is the ghc runtime support for profiling implemented? votes: 9, answers: 2 Read on SO: [32] http://goo.gl/yz7eC * how to achieve “product of two monads” effect? votes: 9, answers: 1 Read on SO: [33] http://goo.gl/pLhVK * Combine two monads when neither has a transformer? votes: 9, answers: 1 Read on SO: [34] http://goo.gl/yw8tr * Why don't type synonyms permit recursion in Haskell? votes: 8, answers: 2 Read on SO: [35] http://goo.gl/hPzVq Until next time, Daniel Santa Cruz References 1. http://yow.eventer.com/events/1004/talks/1054 2. http://www.reddit.com/r/haskell/comments/ovc9s/spj_escape_from_the_ivory_to… 3. http://code.haskell.org/~dons/talks/padl-keynote-2012-01-24.pdf 4. http://www.reddit.com/r/haskell/comments/oxg3c/make_things_now_pragmatic_fp… 5. http://www.haskell.org/pipermail/glasgow-haskell-users/2012-January/021714.… 6. http://www.reddit.com/r/haskell/comments/p0x96/announce_ghc_741_release_can… 7. http://alessandrovermeulen.me/2012/01/26/getting-rid-of-javascript-with-has… 8. http://www.reddit.com/r/haskell/comments/oz27a/web_application_that_uses_uh… 9. http://hdiff.luite.com/ 10. http://www.reddit.com/r/haskell/comments/ozjys/web_app_that_shows_you_the_c… 11. http://www.haskell.org/pipermail/haskell-cafe/2012-January/098704.html 12. http://www.reddit.com/r/haskell/comments/orh4f/combining_regions_and_iterat… 13. http://blog.ezyang.com/2012/01/monadbasecontrol-is-unsound/ 14. http://www.reddit.com/r/haskell/comments/ot5f2/monadbasecontrol_is_unsound_… 15. http://www.yesodweb.com/blog/2012/01/wiki-chat-subsite 16. http://www.reddit.com/r/haskell/comments/oub3p/yesod_example_wiki_markdown_… 17. http://blog.moertel.com/articles/2012/01/26/the-inner-beauty-of-tree-traver… 18. http://www.reddit.com/r/haskell/comments/oyu7d/inner_beauty_of_tree_travers… 19. http://thecostofknowledge.com/ 20. http://www.reddit.com/r/haskell/comments/ozi7i/seem_like_theres_a_boycott_o… 21. http://www.jonmsterling.com/posts/2012-01-12-unifying-monoids-and-monads-wi… 22. http://www.reddit.com/r/haskell/comments/osn5d/unifying_monoids_and_monads_… 23. http://blog.ezyang.com/2012/01/modelling-io/ 24. http://www.reddit.com/r/haskell/comments/ourfu/modelling_io_monadio_and_bey… 25. http://stackoverflow.com/questions/8976423/is-it-a-good-idea-to-compile-a-l… 26. http://stackoverflow.com/questions/9027384/haskell-ghc-what-is-the-time-com… 27. http://stackoverflow.com/questions/9015318/what-to-use-instead-of-a-main-lo… 28. http://stackoverflow.com/questions/9016521/associated-types-and-container-e… 29. http://stackoverflow.com/questions/9036554/undefined-at-the-type-level 30. http://stackoverflow.com/questions/9004937/is-there-a-good-reason-why-delet… 31. http://stackoverflow.com/questions/8963942/using-low-bitsize-integral-types… 32. http://stackoverflow.com/questions/9010808/how-is-the-ghc-runtime-support-f… 33. http://stackoverflow.com/questions/9013329/how-to-achieve-product-of-two-mo… 34. http://stackoverflow.com/questions/9034060/combine-two-monads-when-neither-… 35. http://stackoverflow.com/questions/8963376/why-dont-type-synonyms-permit-re…

1 0

Call for Papers - Workshop on Reversible Computation 2012
by Janis Voigtländer 01 Feb '12

01 Feb '12

============================================================== Call for Papers 4th Workshop on Reversible Computation (RC 2012) July 2nd-3rd, 2012, Copenhagen, Denmark Abstract Submission: March 2nd, 2012 Submission Deadline: March 9th, 2012 http://www.reversible-computation.org ============================================================== Reversible computation has a growing number of promising application areas such as low power design, coding/decoding, program debugging, testing, database recovery, discrete event simulation, reversible algorithms, reversible specification formalisms, reversible programming languages, process algebras, and the modeling of biochemical systems. Furthermore, reversible logic provides a basis for quantum computation with its applications, for example, in cryptography and in the development of highly efficient algorithms. First reversible circuits and quantum circuits have been implemented recently and are seen as promising alternatives to conventional CMOS technology. The workshop will bring together researchers from computer science, mathematics, and physics to discuss new developments and directions for future research in Reversible Computation. This particularly includes applications of reversibility in quantum computation. Research papers, tutorials, tool demonstrations, and work-in-progress reports are within the scope of the workshop. Contributions on the following topics in Reversible Computation are welcome: * Applications * Architectures * Algorithms * Circuit Design * Debugging * Fault Tolerance and Error Correction * Hardware * Information Theory * Physical Realizations * Programming Languages * Quantum Computation * Software * Synthesis * Theoretical Results * Testing * Verification ===== Important Dates ===== - Abstract Submission: March 2nd, 2012 - Submission Deadline: March 9th, 2012 (strict) - Notification to Authors: May 7th, 2012 - Final Version: June 1st, 2012 - Workshop: July 2nd-3rd, 2012 ===== Paper submission ===== Interested researchers are invited to submit full research papers (12 pages maximum), tutorials (12 pages maximum), as well as work-in-progress reports or demonstration papers (6 pages maximum). All submissions will be accepted as PDF file using the LNCS style (more details can be found at the workshop website). A preliminary version of the proceedings will include all accepted papers and will be available at the workshop. Furthermore, authors of selected papers will be invited after the workshop to prepare a final version of their paper to be published in an official publication venue. Paper can be submitted through the following webpage: http://www.reversible-computation.org/2012/cms/index.php?paper_submission ===== Program Chairs ===== Robert Glück University of Copenhagen glueck(a)acm.org Tetsuo Yokoyama Nanzan University tyokoyama(a)acm.org ===== Program Committee ===== * Stéphane Burignat (Gent University, Belgium) * Vincent Danos (Université Paris Diderot, France) * Gerhard W. Dueck (University of New Brunswick, Canada) * Nate Foster (Cornell University, USA) * Luca Gammaitoni (University of Perugia, Italy) * Simon Gay (University of Glasgow, United Kingdom) * Markus Grassl (Centre for Quantum Technologies, Singapore) * Jarkko J. Kari (University of Turku, Finland) * Martin Kutrib (University of Giessen, Germany) * Per Larsson-Edefors (Chalmers University of Technology, Sweden) * Kazutaka Matsuda (Tohoku University, Japan) * D. Michael Miller (University of Victoria, Canada) * Shin-ichi Minato (Hokkaido University, Japan) * Kenichi Morita (Hiroshima University, Japan) * Ilia Polian (University of Passau, Germany) * Michel Schellekens (University College Cork, Ireland) * Irek Ulidowski (University of Leicester, United Kingdom) * Janis Voigtländer (University of Bonn, Germany) * Robert Wille (University of Bremen, Germany) * Paolo Zuliani (Carnegie Mellon University, USA) ===== Workshop Organizer ===== Holger Bock Axelsen University of Copenhagen Department of Computer Science Universitetsparken 1 2100 Copenhagen, Denmark info(a)reversible-computation.org http://www.reversible-computation.org

1 0