April 2012 - Haskell - Haskell.org

PPDP 2012: 2nd Call for papers
by Jon Sneyers 25 Apr '12

25 Apr '12

===================================================================== Call for papers 14th International Symposium on Principles and Practice of Declarative Programming PPDP 2012 Special Issue of Science of Computer Programming (SCP) Leuven, Belgium, September 18-20, 2012 (co-located with LOPSTR 2012) ====================================================================== PPDP 2012 is a forum that brings together researchers from the declarative programming communities, including those working in the logic, constraint and functional programming paradigms, but also embracing a variety of other paradigms such as visual programming, executable specification languages, database languages, and knowledge representation languages. The goal is to stimulate research in the use of logical formalisms and methods for specifying, performing, and analysing computations, including mechanisms for mobility, modularity, concurrency, object-orientation, security, verification and static analysis. Papers related to the use of declarative paradigms and tools in industry and education are especially solicited. Topics of interest include, but are not limited to: * Functional programming * Logic programming * Answer-set programming * Functional-logic programming * Declarative visual languages * Constraint Handling Rules * Parallel implementation and concurrency * Monads, type classes and dependent type systems * Declarative domain-specific languages * Termination, resource analysis and the verification of declarative programs * Transformation and partial evaluation of declarative languages * Language extensions for security and tabulation * Probabilistic modelling in a declarative language and modelling reactivity * Memory management and the implementation of declarative systems * Practical experiences and industrial application This year the conference will be co-located with the 22nd International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2012) and held in cooperation with ACM SIGPLAN. The conference will be held in Leuven, Belgium. Previous symposia were held at Odense (Denmark), Hagenberg (Austria), Coimbra (Portugal), Valencia (Spain), Wroclaw (Poland), Venice (Italy), Lisboa (Portugal), Verona (Italy), Uppsala (Sweden), Pittsburgh (USA), Florence (Italy), Montreal (Canada), and Paris (France). 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, conference, or workshop with refereed proceedings. Work that already appeared in unpublished or informally published workshop proceedings may be submitted (please contact the PC chair in case of questions). Proceedings will be published by ACM Press* After the symposium, a selection of the best papers will be invited to extend their submissions in the light of the feedback solicited at the symposium. The papers are expected to include at least 25% extra material over and above the PPDP version. Then, after another round of reviewing, these revised papers will be published in a special issue of SCP with a target publication date by Elsevier of 2013. Important Dates: Abstract Submission: May 28, 2012 Paper submission: May 31, 2012 Notification: July 6, 2012 Camera-ready: July 18, 2012 Symposium: September 19-21, 2012 Invites for SCP: September 26, 2012 Submission of SCP: December 12, 2012 Notification from SCP: February 7, 2013 Camera-ready for SCP: March 7, 2013 Authors should submit an electronic copy of the paper (written in English) in PDF. Each submission must include on its first page the paper title; authors and their affiliations; abstract; and three to four keywords. The keywords will be used to assist us in selecting appropriate reviewers for the paper. Papers should consist of no more than 12 pages, formatted following the ACM SIG proceedings template (option 1). The 12 page limit must include references but excludes well-marked appendices not intended for publication. Referees are not required to read the appendices, and thus papers should be intelligible without them. Invited speakers: Torsten Schaub, University of Potsdam, Germany Juergen Giesl, RWTH Aachen, Germany (shared with LOPSTR) Program Committee: Slim Abdennadher German University in Cairo, Egypt Puri Arenas Complutense University of Madrid, Spain Marcello Balduccini Kodak Research Labs, USA Amir Ben-Amram Tel-Aviv Academic College, Israel Philip Cox Dalhousie University, Canada Marina De Vos University of Bath, UK Martin Erwig Oregon State University, USA Martin Gebser University of Potsdam, Germany Jacob Howe City University London, UK Joxan Jaffar National University of Singapore, Singapore Gabriele Keller University of New South Wales, Australia Andy King University of Kent, UK Julia Lawall INRIA Paris, France Rita Loogen Philipps-Universitat Marburg, Germany Greg Michaelson Heriot-Watt University, UK Matthew Might University of Utah, USA Henrik Nilsson University of Nottingham, UK Catuscia Palamidessi INRIA Saclay and Ecole Polytechnique, France Kostis Sagonas Uppsala University, Sweden and NTUA, Greece Taisuke Sato Tokyo Institute of Technology, Japan Peter Schneider-Kamp University of Southern Denmark, Denmark Tom Schrijvers University of Ghent, Belgium Terrance Swift Universidade Nova de Lisboa, USA Mirek Truszczynski University of Kentucky, USA Stephanie Weirich University of Pennsylvania, USA Program Chair: Andy King School of Computing, University of Kent Canterbury, CT2 7NF, UK General Co-Chairs: Daniel De Schreye and Gerda Janssens Department of Computer Science K.U.Leuven, Celestijnenlaan 200 A, B-3001 Heverlee, Belgium * Confirmation pending

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HaL-7, 2012-07-13, Call for submissions
by Henning Thielemann 23 Apr '12

23 Apr '12

Call for submissions and Save the date for our local Haskell Workshop in Halle/Saale, Germany. Tutorials, talks, demonstrations ... everything welcome. Workshop language is German (mainly), and English (by request). Submission deadline: May, 21, Workshop date: June, 22 Workshop homepage: http://iba-cg.de/hal7.html The complete call in German: ------------------------------------------------- Aufruf zum Einreichen von Beiträgen und Hinweis zum Vormerken des Termins Was: Haskell-Treffen HaL-7 Wann: Freitag, 13.07.2012 Wo: Institut für Informatik an der Martin-Luther-Universität in Halle an der Saale Wir suchen Vorträge zu Haskell im Besonderen und der funktionalen Programmierung im Allgemeinen, zum Beispiel zu den Themen * Neues von Sprache, Bibliotheken, Werkzeugen, * Anwendungen von Kunst bis Industrie, * Lehre an Schulen und Hochschulen, gerne aber auch zu anderen Themen. Die Beiträge können präsentiert werden als * Tutorium (60 .. 90 min) * Vortrag (30 min) * Demonstration, künstlerische Aufführung Die Veranstaltungssprache ist Deutsch, in begründeten Ausnahmen Englisch. Presentations will be given in German but we can switch to English if requested. Bitte reichen Sie Kurzfassungen der Beiträge ein (2 bis 4 Seiten), die dem Programmkomitee eine Einschätzung ermöglichen. Die Kurzfassung soll mit einer Zusammenfassung (10 Zeilen) beginnen und einem Literaturverzeichnis enden. Teilnehmer des Workshops sind Interessenten (keine Erfahrung mit Haskell/FP), Anfänger (wenig Erfahrung) und Experten. Wir bitten die Vortragenden, die Zielgruppe des Beitrags anzugeben und die nötigen Vorkenntnisse zu beschreiben. Bei Tutorien sollen Teilnehmer auf eigenen Rechnern arbeiten. Bitte beschreiben Sie dazu die vorher zu installierende Software. Schicken Sie Beitragsvorschläge als PDF-Dokument bis zum 21.05.2012 per Mail an hal-committee at iba-cg punkt de oder an ein Mitglied des Programmkomitees. Programmkomitee * Henning Thielemann - Univ. Halle (Vorsitzender), * Petra Hofstedt - BTU Cottbus, * Alf Richter - iba CG Leipzig, * Uwe Schmidt - FH Wedel, * Janis Voigtländer - Univ. Bonn, * Johannes Waldmann - HTWK Leipzig. Mit besten Grüßen Henning Thielemann

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WING 2012: Call for Presentations
by Gudmund Grov 23 Apr '12

23 Apr '12

[Please post - apologies for multiple copies.] ---------------------------------------------------- WING 2012 - 4th International Workshop on INvariant Generation http://cs.nyu.edu/acsys/wing2012/ June 30, 2012 Manchester, UK (a satellite Workshop of IJCAR 2012) ---------------------------------------------------- --- Call for Presentations --- General ------- The ability to automatically extract and synthesize auxiliary properties of programs has had a profound effect on program analysis, testing, and verification over the last several decades. A key impediment for program verification is the overhead associated with providing, debugging, and verifying auxiliary invariant annotations. This workshop aims to bring together researchers from the diverse field of invariant generation to discuss recent developments. Scope ----- We encourage ONE-PAGE ABSTRACT submissions on work in progress, new ideas, tools under development, as well as work by PhD students, to be presented at WING 2012. Relevant topics include (but are not limited to) the following: * Program analysis and verification * Inductive Assertion Generation * Inductive Proofs for Reasoning about Loops * Applications to Assertion Generation using the following tools: - Abstract Interpretation, - Static Analysis, - Model Checking, - Theorem Proving, - Theory Formation, - Algebraic Techniques * Tools for inductive assertion generation and verification * Alternative techniques for reasoning about loops Submission ---------- Submissions need not be original. Extended versions of submissions may have been published previously, or submitted concurrently with or after WING 2012 to another workshop, conference or a journal. Submission is by email to: wing2012(a)easychair.org Please submit a ONE-PAGE abstract in PDF. Important Dates --------------- Submission deadline: May 15, 2012 Notification of acceptance: May 18, 2012 Workshop: June 30, 2012 Invited Speakers ---------------- * Aditya Nori (Microsoft Research) Committee ----------------- Program Chairs: * Gudmund Grov (University of Edinburgh, UK) * Thomas Wies (New York University, USA) Program Committee: * Clark Barrett (New York University, USA) * Nikolaj Bjorner (Microsoft Research, USA) * Gudmund Grov (University of Edinburgh, UK) * Ashutosh Gupta (IST Austria) * Bart Jacobs (Katholieke Universiteit Leuven, Belgium) * Moa Johansson (Chalmers University of Technology, Sweden) * Laura Kovacs (Vienna University of Technology, Austria) * David Monniaux (VERIMAG, France) * Enric Rodriguez Carbonell (Technical University of Catalonia, Spain) * Helmut Veith (Vienna University of Technology, Austria) * Thomas Wies (New York University, USA) Student Support ---------------- Students will pay a reduced fee, and the difference will be reimbursed after the workshop. Publication ----------- Extended versions of accepted contributions may be submitted later to a special issue of the Journal of Science of Computer Programming. -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

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Types of when and unless in Control.Monad
by Andreas Abel 22 Apr '12

22 Apr '12

In Control.Monad, when has type when :: Monad m => Bool -> m () -> m () I think this type should be generalized to when :: Monad m => Bool -> m a -> m () to avoid silly "return ()" statements like in when cond $ do monadicComputationWhoseResultIWantToDiscard return () Cheers, Andreas P.S.: A more systematic solution would be to change the Haskell language by either introducing a Top type which is the supertype of everything and use it instead of (). Alternatively, make () the top type and interpret matching against the empty tuple as just computing the weak head normal form and then discarding the result. The latter is needed to preserve the current behavior of (\ () -> bla) (error "raised") vs. (\ _ -> bla) (error "not raised") -- Andreas Abel <>< Du bist der geliebte Mensch. Theoretical Computer Science, University of Munich Oettingenstr. 67, D-80538 Munich, GERMANY andreas.abel(a)ifi.lmu.de http://www2.tcs.ifi.lmu.de/~abel/

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Call for Papers - Haskell Symposium 2012 - six weeks to go
by Janis Voigtländer 21 Apr '12

21 Apr '12

======================================================================== "Haskell 2012" ACM SIGPLAN Haskell Symposium 2012 Copenhagen, Denmark 13th September, 2012 (directly after ICFP) CALL FOR PAPERS http://www.haskell.org/haskell-symposium/2012/ ======================================================================== The ACM SIGPLAN Haskell Symposium 2012 will be co-located with the 2012 International Conference on Functional Programming (ICFP), in Copenhagen, Denmark. The purpose of the Haskell Symposium is to discuss experiences with Haskell and future developments for the language. Topics of interest include, but are not limited to: * 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 treatments of the semantics of the present language or future extensions, type systems, 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, in the form of profilers, tracers, debuggers, pre-processors, testing tools, and suchlike; * Applications, using Haskell for scientific and symbolic computing, database, multimedia, telecom and web applications, and so forth; * Functional Pearls, being elegant, instructive examples of using Haskell; * Experience Reports, general practice and experience with Haskell, e.g., in an education or industry context. Papers in the latter three categories 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. (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, based on running (perhaps prototype) software rather than necessarily on novel research results. Such short demo proposals should explain why a demonstration would be of interest to the Haskell community. 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. In addition to printed proceedings, 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 proposals, assessed for relevance by the PC, will be published on the symposium web page, but not formally published in the proceedings. Submission Details: =================== * Abstract Submission: Thu 31st May 2012 * Submission Deadline: Sun 3rd June 2012, 11:00 am, UTC * Author Notification: Wed 27th June 2012 * Final Papers Due : Tue 10th July 2012 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. Demo proposals are limited to 2-page abstracts, in the same format. "Functional Pearls", "Experience Reports", and "Demo 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=haskell2012 Programme Committee: ==================== * Amal Ahmed, Northeastern University * Jost Berthold, University of Copenhagen * Nils Anders Danielsson, University of Gothenburg * Iavor Diatchki, Galois Inc. * Jeremy Gibbons, University of Oxford * Jurriaan Hage, Utrecht University * Zhenjiang Hu, National Institute of Informatics Tokyo * Daan Leijen, Microsoft Research * Ben Lippmeier, University of New South Wales * Simon Peyton Jones, Microsoft Research * Colin Runciman, University of York * Eijiro Sumii, Tohoku University * Janis Voigtländer (chair), University of Bonn * Brent Yorgey, University of Pennsylvania Links: ====== * http://www.haskell.org/haskell-symposium (the permanent web page of the Haskell Symposium) * http://www.haskell.org/haskell-symposium/2012 (the 2012 Haskell Symposium web page) * http://www.icfpconference.org/icfp2012 (the ICFP 2012 web page) -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

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ANN: yeganesh-2.5
by wagnerdm＠seas.upenn.edu 21 Apr '12

21 Apr '12

Today heralds the release of version 2.5 of the venerable yeganesh[1] menu. The suckless team produces a small program named dmenu[2] which acts like a normal Unix pipe program, accepting input on stdin and producing output on stdout, with the one caveat that it sticks the user in between. It launches a very small menu, presenting the user with each of the lines of stdin as choices, and prints the chosen text as a single line to stdout. This is very convenient for lightweight, GUI-less programs and scripts that need some minimal interaction; however, it is completely memoryless. Yeganesh wraps dmenu to add some memory: it records which choices the user has made in the past, and promotes popular choices to the front of the menu on future runs. See the website[1] for screenshots. New in this release: * Switching away from Read as the cache file parser reduced startup time by a factor of eight. (Caches in the old format will be transparently upgraded.) * When running in --executables mode, broken symlinks no longer sabotage their siblings in the filesystem tree. * Minor change to command-line parsing to preserve consistency with GNU-style command lines. (Any command line that used to work will still work, and will behave the same; however, some lines that were rejected before are now accepted and passed on to dmenu.) To try it out: 1. Install dmenu via your package manager, or from source (it's quite small!). wget http://dl.suckless.org/tools/dmenu-4.5.tar.gz tar xf dmenu-4.5.tar.gz cd dmenu-4.5 make install 2. Install yeganesh from Hackage. cabal install yeganesh 3. Run yeganesh; for example, to choose a file in your current directory, then see that file float to the top of your choices, try ls | yeganesh ls | yeganesh Features: * One common use case for choosing an executable from your $PATH to launch; yeganesh will scan your $PATH for you when launched in the --executables mode. * Multiple popularity profiles allow separate dmenu consumers to have separate memories. (For example, I have separate profiles for launching GUI and shell programs.) * Sometimes you say something embarassing; use the --filter mode to forget it. Enjoy! ~d [1] http://dmwit.com/yeganesh [2] http://tools.suckless.org/dmenu/

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Erlang workshop call for papers
by John Hughes 20 Apr '12

20 Apr '12

Why not adapt some cool Haskell ideas to Erlang too? Six weeks to go... John Hughes [http://www.erlang.org/workshop/2011/erlang090.gif] CALL FOR PAPERS Eleventh ACM SIGPLAN Erlang Workshop Copenhagen, Denmark Friday, September 14, 2012 [http://www.erlang.org/workshop/2011/acm_logo_wordmark.gif] A satellite event of the 17th ACM SIGPLAN International Conference on Functional Programming (ICFP 2012<http://icfpconference.org/icfp2012/>). Erlang is a concurrent, distributed functional programming language aimed at systems with requirements on massive concurrency, soft real time response, fault tolerance, and high availability. It has been available as open source for over a decade, creating a community that actively contributes to its already existing rich set of libraries and applications. Originally created for telecom applications, its usage has spread to other domains including e-commerce, banking, databases, and computer telephony and messaging. Erlang programs are today among the largest applications written in any functional programming language. These applications offer new opportunities to evaluate functional programming and functional programming methods on a very large scale and suggest new problems for the research community to solve. This workshop will bring together the open source, academic, and industrial programming communities of Erlang. It will enable participants to familiarize themselves with recent developments on new techniques and tools tailored to Erlang, novel applications, draw lessons from users' experiences and identify research problems and common areas relevant to the practice of Erlang and functional programming. We invite three sorts of submissions. * Technical papers describing language extensions, critical discussions of the status quo, formal semantics of language constructs, program analysis and transformation, virtual machine extensions and compilation techniques, implementations and interfaces of Erlang in/with other languages, and new tools (profilers, tracers, debuggers, testing frameworks, etc.). The maximum length for technical papers is restricted to 12 pages. * Practice and application papers describing uses of Erlang in the "real-world", Erlang libraries for specific tasks, experiences from using Erlang in specific application domains, reusable programming idioms and elegant new ways of using Erlang to approach or solve a particular problem. The maximum length for the practice and application papers is restricted to 12 pages. Note that this is a maximum length: we welcome shorter papers also; the program committee will evaluate all papers on an equal basis independent of their lengths. * Poster presentations describing topics related to the workshop goals. Each of them includes max 2 pages of the abstract and summary. Presentations in this category will be given an hour of shared simultaneous demonstration time. Workshop Chair * Torben Hoffmann, Issuu, Denmark Program Chair * John Hughes, Chalmers University of Technology/Quviq AB, Gothenburg, Sweden Program Committee (Note: the Workshop and Program Chairs are also committee members) * Clara Benac Earle, Technical University of Madrid, Madrid, Spain * Scott Lystig Fritchie, Basho Technologies, USA * Simon Peyton Jones, Microsoft Research, Cambridge, England * Tamas Kozsik, Eötvös Loránd University, Budapest, Hungary * Kenneth Lundin, Ericsson AB, Stockholm, Sweden * Kostis Sagonas, Uppsala University, Uppsala, Sweden * Erik Stenman, Klarna AB, Stockholm, Sweden * Kresten Krab Thorup, Trifork A/S, Aarhus, Denmark * Steve Vinoski, Basho Technologies, USA Important Dates * Submission deadline: Sunday, June 3, 2012 * Author notification: Wednesday, June 27, 2012 * Final submission for the publisher: Tuesday, July 10, 2012 * Workshop date: Friday, September 14, 2012 Instructions to authors Papers must be submitted online via EasyChair (via the "Erlang2012" event). The submission page is https://www.easychair.org/conferences/?conf=erlang2012. Submitted papers should be in portable document format (PDF), formatted using the ACM SIGPLAN style guidelines. Each submission must adhere to SIGPLAN's republication policy. Violation risks summary rejection of the offending submission. Accepted papers will be published by the ACM and will appear in the ACM Digital Library. Paper submissions will be considered for poster submission in the case that they are not accepted as full papers. Venue & Registration Details For registration, please see the ICFP 2012 web site. Related Links * ICFP 2012 web site: http://www.icfpconference.org/icfp2012/ * Past ACM SIGPLAN Erlang workshops: http://www.erlang.org/workshop/ * Open Source Erlang: http://www.erlang.org/ * EasyChair submission site: https://www.easychair.org/account/signin.cgi?conf=erlang2012 * Author Information for SIGPLAN Conferences: http://www.sigplan.org/authorInformation.htm

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ANNOUNCE: curlhs-0.0.1, bindings to libcurl
by Krzysztof Kardzis 19 Apr '12

19 Apr '12

Hello! I'm pleased to announce the first release of curlhs package (curlhs-0.0.1), a new Haskell bindings to libcurl, the multiprotocol file transfer library which powers popular curl tool. hackage: http://hackage.haskell.org/package/curlhs github: https://github.com/kkardzis/curlhs Package is distributed under ISC License (MIT/BSD-style, see LICENSE file for details). Current version of curlhs follows libcurl in version 7.25.0. It is also possible to use curlhs with older versions of libcurl, but some features may not be available then (curlhs should easily compile with libcurl from version 7.20.0 upward). Bindings are not complete, there is still a lot of work to do, but I think that for many simple tasks it's enough. The aim is to provide a mid-level interface to libcurl, which will be fairly complete and close to the original API. With this initial release I hope to gain some feedback from potential users. Any comments and suggestions are welcome. Greetings, Krzysztof Kardzis

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ANNOUNCE: graphviz-2999.13.0.0
by Ivan Lazar Miljenovic 19 Apr '12

19 Apr '12

I'm hoping the second part of the version number isn't ominous, but I've just uploaded the latest release in my bindings for the Graphviz suite of graph visualisation tools. The changes in this release are: * Added support for the `osage` and `patchwork` visualisation tools, available as of Graphviz-2.28.0. * Updated attributes as of Graphviz-2.28.0: - `SVG` colors are now supported, and the support for different colors has been revamped. - `overlap=false` is now equivalent to `overlap=prism` and the `RemoveOverlaps` option has been removed. - `LabelScheme` and `Rotation` are new attributes for use with `sfdp`. - `Scale` is a new attribute for use with `twopi`. - Add new italics, bold, underline, superscript and subscript options for HTML-like labels. - `LHeight` and `LWidth` for getting the height and width of the root graph and clusters. * Updated attributes from the current development branch of Graphviz (i.e. 2.29.*). Please note that these will probably not work yet, but are implemented now for future-proofing. - A new style for edges: `Tapered`. - `XLabel` allows you to specify labels external to a node or edge. `ForceLabels` allow you to specify that these should be drawn even when they will cause overlaps. - `ImagePath` allows you to specify where to search for images. - HTML-like labels now support `ID` values as well as horizontal and vertical rules. - `BgColor` and `FillColor` now take a list of colors: this allows gradient fills for graphs, clusters and nodes. The `Radial` style and `GradientAngle` are also used for this purpose. - `FillColor` is now used by edges to set the color of any arrows. - [WebP](http://en.wikipedia.org/wiki/WebP) output support added. * Other attribute changes: - Use a specified data type for the `Ordering` attribute rather than an arbitrary `Text` value, and provide a documented wrapper in `Data.GraphViz.Attributes`. - `Bb` has been renamed `BoundingBox`. - `ID` now only takes `EscString` (a type alias for `Text`) values rather than arbitrary `Label`s. - The `Data.GraphViz.Attributes.HTML` module has had all values re-named and is now meant to be imported qualified. It is also no longer re-exported from `Data.GraphViz.Attributes.Complete`. * The `ToGraphID` class provides a common wrapper to help create cluster identifiers, etc. * Cabal's `Test-Suite` functionality is now used. As part of this, the `Data.GraphViz.Testing` module and sub-modules are no longer exported by the library. * The new `Benchmark` support in Cabal-1.14 is now used for the benchmark script. * Dropped support for base-3. * The `Data.GraphViz.State` module is no longer exposed, as there's no need for users to use it. * Bugfixes: - Some corner cases in canonicalisation prevented it from being idempotent. - The `TestParsing` script will no longer crash and refuse to continue if an IO-based error (e.g. unable to successfully call `dot`) occurs. - A typo was spotted by **Gabor Greif**. -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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Haskell Weekly News: Issue 223
by Daniel Santa Cruz 19 Apr '12

19 Apr '12

Welcome to issue 223 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week of April 8 to 14, 2012. Quotes of the Week * merijn: I'm tempted to just do unsafePerformIO newEmptyMVar at the top level quicksilver: I can't really be expected to deal with your sinfulness. That's between you and your god. * acowley: Good haskell code is 20 LANGUAGE pragmas, 40 imports, then one line of perl. * deggis: oh. running GHC HEAD. must try that next week if coffee just someday isn't enough * dmwit: hGetContents does not close its handle. dmwit: hGetContents semicloses its handle. * monochrom: isTrue = (unsafeCoerce :: Either a b -> Bool) . (unsafeCoerce :: Maybe c -> Either a b) . (unsafeCoerce :: Bool -> Maybe c) * dmwit: For basically all good properties P, IEEE 754 is not P. * Cale: Little known fact: For any positive integer n, the infinite sequence of Project Euler problems has only finitely many elements whose solution is not divisible by n. Top Reddit Stories * Announcing Yesod 1.0 Domain: yesodweb.com, Score: 101, Comments: 42 On Reddit: [1] http://goo.gl/izD19 Original: [2] http://goo.gl/oTSto * Why reasoning about space usage in Haskell is hard Domain: ro-che.info, Score: 63, Comments: 14 On Reddit: [3] http://goo.gl/yIkI4 Original: [4] http://goo.gl/IAQtu * GHC HEAD now has type level natural number/ literals Domain: github.com, Score: 63, Comments: 18 On Reddit: [5] http://goo.gl/GfGbB Original: [6] http://goo.gl/Lkp6v * Working Together Domain: yesodweb.com, Score: 62, Comments: 31 On Reddit: [7] http://goo.gl/o3G85 Original: [8] http://goo.gl/jBdJA * How less is more : polymorphic types can improve safety even in monomorphic functions Domain: blog.malde.org, Score: 61, Comments: 13 On Reddit: [9] http://goo.gl/fzUlO Original: [10] http://goo.gl/WHE3A * A Hopefully Fair and Useful Comparison of Haskell Web Frameworks Domain: softwaresimply.blogspot.com, Score: 60, Comments: 30 On Reddit: [11] http://goo.gl/WuDuL Original: [12] http://goo.gl/DXBA8 * First impressions of Haskell: A review of my Haskell adventure Domain: binarysculpting.com, Score: 46, Comments: 36 On Reddit: [13] http://goo.gl/gG0fl Original: [14] http://goo.gl/ZqUT3 * A "radix tree" import syntax? Domain: self.haskell, Score: 41, Comments: 26 On Reddit: [15] http://goo.gl/kBOLZ Original: [16] http://goo.gl/kBOLZ * Using ContT to please the eye Domain: self.haskell, Score: 28, Comments: 15 On Reddit: [17] http://goo.gl/hbFrs Original: [18] http://goo.gl/hbFrs * Designing a DCPU-16 emulator in Haskell: on determinism and I/O Domain: jaspervdj.be, Score: 28, Comments: 6 On Reddit: [19] http://goo.gl/KHIgP Original: [20] http://goo.gl/NT89i Top StackOverflow Questions * What are type quantifiers? votes: 15, answers: 3 Read on SO: [21] http://goo.gl/d3hnH * Haskell: How does 'atomicModifyIORef' work? votes: 12, answers: 2 Read on SO: [22] http://goo.gl/3b5dK * Is there a runtime penalty associated with typeclasses? votes: 12, answers: 1 Read on SO: [23] http://goo.gl/Isw7k * Timing out pure functions votes: 11, answers: 1 Read on SO: [24] http://goo.gl/aTzVG * Haskell - simple constructor comparison (?) function votes: 11, answers: 3 Read on SO: [25] http://goo.gl/ZC6CC * Partial Application with Infix Functions votes: 10, answers: 3 Read on SO: [26] http://goo.gl/QvabF * Haskell: Why is there no type mismatch (and why does this compile)? votes: 9, answers: 2 Read on SO: [27] http://goo.gl/1gxFE * “Dependent optional” data in Haskell votes: 9, answers: 4 Read on SO: [28] http://goo.gl/9K5Wx * How can I help SpecConstr in GHC? votes: 8, answers: 2 Read on SO: [29] http://goo.gl/PGa4C * How to get good performance when writing a list of integers from 1 to 10 million to a file? votes: 7, answers: 2 Read on SO: [30] http://goo.gl/Kym6r * Efficiently turn a ByteString into a hex representation votes: 7, answers: 1 Read on SO: [31] http://goo.gl/aq2ct Until next time, Daniel Santa Cruz References 1. http://www.yesodweb.com/blog/2012/04/announcing-yesod-1-0 2. http://www.reddit.com/r/haskell/comments/s0tr2/announcing_yesod_10/ 3. http://ro-che.info/articles/2012-04-08-space-usage-reasoning.html 4. http://www.reddit.com/r/haskell/comments/rzu8a/why_reasoning_about_space_us… 5. https://github.com/ghc/packages-base/blob/b5b5ec18819fb85ebf1bdb6345ac03178… 6. http://www.reddit.com/r/haskell/comments/s0vln/ghc_head_now_has_type_level_… 7. http://www.yesodweb.com/blog/2012/04/working-together 8. http://www.reddit.com/r/haskell/comments/s2ei5/working_together/ 9. http://blog.malde.org/posts/polymorphic-types-are-safer.html 10. http://www.reddit.com/r/haskell/comments/s7q3b/how_less_is_more_polymorphic… 11. http://softwaresimply.blogspot.com/2012/04/hopefully-fair-and-useful-compar… 12. http://www.reddit.com/r/haskell/comments/s3pbm/a_hopefully_fair_and_useful_… 13. http://binarysculpting.com/2012/04/12/a-review-of-my-haskell-adventure/ 14. http://www.reddit.com/r/haskell/comments/s6okb/first_impressions_of_haskell… 15. http://www.reddit.com/r/haskell/comments/s2o8p/a_radix_tree_import_syntax/ 16. http://www.reddit.com/r/haskell/comments/s2o8p/a_radix_tree_import_syntax/ 17. http://www.reddit.com/r/haskell/comments/s49kk/using_contt_to_please_the_ey… 18. http://www.reddit.com/r/haskell/comments/s49kk/using_contt_to_please_the_ey… 19. http://jaspervdj.be/posts/2012-04-12-st-io-dcpu-16.html 20. http://www.reddit.com/r/haskell/comments/s5xqb/designing_a_dcpu16_emulator_… 21. http://stackoverflow.com/questions/10062253/what-are-type-quantifiers 22. http://stackoverflow.com/questions/10102881/haskell-how-does-atomicmodifyio… 23. http://stackoverflow.com/questions/10148897/is-there-a-runtime-penalty-asso… 24. http://stackoverflow.com/questions/10071560/timing-out-pure-functions 25. http://stackoverflow.com/questions/10112733/haskell-simple-constructor-comp… 26. http://stackoverflow.com/questions/10131300/partial-application-with-infix-… 27. http://stackoverflow.com/questions/10091874/haskell-why-is-there-no-type-mi… 28. http://stackoverflow.com/questions/10136222/dependent-optional-data-in-hask… 29. http://stackoverflow.com/questions/10145954/how-can-i-help-specconstr-in-ghc 30. http://stackoverflow.com/questions/10080273/how-to-get-good-performance-whe… 31. http://stackoverflow.com/questions/10099921/efficiently-turn-a-bytestring-i…

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