November 2006 - Haskell

Announcing Djinn, version 2004-12-11, a coding wizard
by Lennart Augustsson 07 Apr '11

07 Apr '11

Howdy, y'all! I've written a small program that takes a (Haskell) type and gives you back a function of that type if one exists. It's kind of fun, so I thought I'd share it. It's probably best explained with a sample session. calvin% djinn Welcome to Djinn version 2005-12-11. Type :h to get help. # Djinn is interactive if not given any arguments. # Let's see if it can find the identity function. Djinn> f ? a->a f :: a -> a f x1 = x1 # Yes, that was easy. Let's try some tuple munging. Djinn> sel ? ((a,b),(c,d)) -> (b,c) sel :: ((a, b), (c, d)) -> (b, c) sel ((_, v5), (v6, _)) = (v5, v6) # We can ask for the impossible, but then we get what we # deserve. Djinn> cast ? a->b -- cast cannot be realized. # OK, let's be bold and try some functions that are tricky to write: # return, bind, and callCC in the continuation monad Djinn> type C a = (a -> r) -> r Djinn> returnC ? a -> C a returnC :: a -> C a returnC x1 x2 = x2 x1 Djinn> bindC ? C a -> (a -> C b) -> C b bindC :: C a -> (a -> C b) -> C b bindC x1 x2 x3 = x1 (\ c15 -> x2 c15 (\ c17 -> x3 c17)) Djinn> callCC ? ((a -> C b) -> C a) -> C a callCC :: ((a -> C b) -> C a) -> C a callCC x1 x2 = x1 (\ c15 _ -> x2 c15) (\ c11 -> x2 c11) # Well, poor Djinn has a sweaty brow after deducing the code # for callCC so we had better quit. Djinn> :q Bye. To play with Djinn do a darcs get http://darcs.augustsson.net/Darcs/Djinn or get http://darcs.augustsson.net/Darcs/Djinn/Djinn.tar.gz Then just type make. (You need a Haskell 98 implementation and some libraries.) And then start djinn. For the curious, Djinn uses a decision procedure for intuitionistic propositional calculus due to Roy Dyckhoff. It's a variation of Gentzen's LJ system. This means that (in theory) Djinn will always find a function if one exists, and if one doesn't exist Djinn will terminate telling you so. This is the very first version, so expect bugs. :) Share and enjoy. -- Lennart

8 13

Haskell-mode 2.0
by Stefan Monnier 02 Feb '09

02 Feb '09

I have recently taken over maintainership of Haskell-mode, and after making a bunch of changes, I figured it would be a good idea to make a new release. You can find this new release at: http://www-perso.iro.umontreal.ca/~monnier/elisp/ If you think it should also be found at http://www.haskell.org/haskell-mode/, then please tell John Peterson to get back to me (my email to him seem to go straight to the bitbucket. John?). This release has several changes that have all been only lightly tested, especially w.r.t compatibility with various Emacsen. See appended the NEWS file that describes some of the notewirthy changes. Stefan Changes since 1.45: * keybindings C-c <char> have been replaced by C-c C-<char> so as not to collide with minor modes. * The following modules are now automatically activated without having to add anything to haskell-mode-hook: haskell-font-lock (just turn on global-font-lock-mode). haskell-decl-scan (just bind `imenu' to some key). * In recent Emacsen, haskell-doc hooks into eldoc-mode. * haskell-hugs and haskell-ghci are superceded by inf-haskell. * Indentation rules have been improved when using layout inside parens/braces. * Symbols like -> and \ can be displayed as actual arrows and lambdas. See haskell-font-lock-symbols. * Tweaks to the font-lock settings. Among other things paren-matching with things like \(x,y) should work correctly now. * New maintainer <monnier(a)gnu.org>.

3 6

ANNOUNCE: Haskell Communities & Activities Report (11th ed., November 2006)
by Andres Loeh 30 Nov '06

30 Nov '06

On behalf of the many, many contributors, I am pleased to announce that the Haskell Communities and Activities Report (11th edition, November 2006) http://www.haskell.org/communities/ is now available from the Haskell Communities home page in several formats: PDF, for screenreading as well as printing, HTML, for those of you who prefer not to deal with plugins or external viewers, and PostScript, for those of you who have nice quick printers that do not grok PDF. Many thanks go to all the people that contributed to this report, both directly, by sending in descriptions, and indirectly, by doing all the interesting things that are reported. I hope you will find it as interesting a read as we did. If you haven't encountered the Haskell Communities and Activities Reports before, you may like to know that the first of these reports was published in November 2001. Their goal is to improve the communication between the increasingly diverse groups, projects and individuals working on, with, or inspired by Haskell. The idea behind these reports is simple: Every six months, a call goes out to all of you enjoying Haskell to contribute brief summaries of your own area of work. Many of you respond (eagerly, unprompted, and well in time for the actual deadline ;) ) to the call. The editor collects all the contributions into a single report and feeds that back to the community. When we try for the next update, six months from now, you might want to report on your own work, project, research area or group as well. So, please put the following into your diaries now: ---------------------------------------- End of April 2007: target deadline for contributions to the May 2006 edition of the HC&A Report ---------------------------------------- Unfortunately, many Haskellers working on interesting projects are so busy with their work that they seem to have lost the time to follow the Haskell related mailing lists and newsgroups, and have trouble even finding time to report on their work. If you are a member, user or friend of a project so burdened, please find someone willing to make time to report and ask them to `register' with the editor for a simple e-mail reminder in the middle of April (you could point me to them as well, and we can then politely ask if they want to contribute, but it might work better if you do the initial asking). Of course, they will still have to find the ten to fifteen minutes to draw up their report, but maybe we can increase our coverage of all that is going on in the community. Feel free to circulate this announcement further in order to reach people who might otherwise not see it. Enjoy! Andres Loeh <hcar at haskell.org> -- Haskell Communities and Activities Report (http://haskell.org/communities)

1 0

ANNOUNCE: Visual Haskell prerelease 0.2
by Krasimir Angelov 30 Nov '06

30 Nov '06

Hello Haskellers, I am happy to announce that there is a prerelease version of Visual Haskell on: http://www.haskell.org/visualhaskell This is the first version that is: - available for both VStudio 2003 and VStudio 2005 - distributed with a stable GHC version (6.6) This is still prerelease version but if there aren't any bug reports in the next few days I will just rename it to release. Many thanks to Simon Marlow, Brian Smith, Wayne Vucenic, Jared Updike and Pepe Iborra that helped me with the preparation of this new release. Cheers, Krasimir

6 11

(last) call for participation: HAL next Tuesday
by Johannes Waldmann 30 Nov '06

30 Nov '06

Dear all, this is a reminder for the Haskell meeting to be held in Leipzig, Germany, Tuesday next week (December 5th) http://www.iba-cg.de/haskell.html If you want to come, register now. As we have a number of non-local attendees already, we might append a "functional breakfast" the next morning. -- -- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 -- ---- http://www.imn.htwk-leipzig.de/~waldmann/ -------

1 0

LDTA 07 CfP - deadline extended
by Eric Van Wyk 29 Nov '06

29 Nov '06

[DEADLINE EXTENDED: Title and Abstract due Dec 4, Papers due Dec 11] Call for Papers for Seventh Workshop on Language Descriptions, Tools and Applications LDTA 2007 A satellite event of ETAPS 2007 March 25, 2007 in Braga, Portugal (Cooperation with ACM SIGPLAN to be confirmed) http://www.di.uminho.pt/ldta07 Scope: The aim of this one-day workshop is to bring together researchers from academia and industry interested in the field of formal language definitions and language technologies, with a special emphasis on tools developed for or with these language definitions. This active area of research involves the following basic technologies: - Program analysis, transformation, and generation - Formal analysis of language properties - Automatic generation of language processing tools For example, language definitions can be augmented in a manner so that not only compilers or interpreters can be automatically generated but also other tools such as syntax-directed editors, debuggers, partial evaluators, test generators, and documentation generators. Although various specification formalisms like attribute grammars, action semantics, operational semantics, and algebraic approaches have been developed, they are not widely exploited in current practice. It is the aim of the LDTA workshops to bridge this gap between theory and practice. Among others, the following application domains can benefit from advanced language technologies: - Software component models and modeling languages - Re-engineering and re-factoring - Aspect-oriented programming - Domain-specific languages - XML processing - Visualization and graph transformation - Programming environments such as Eclipse, NetBeans and Visual Studio - Modern runtime platforms including .Net, Rotor, Java Virtual Machine The workshop welcomes contributions on all aspects of formal language definitions, with special emphasis on applications and tools developed for or with these language definitions. Experience papers describing novel or compelling uses of language definition-based methods in real world projects are particularly sought. Invited Speaker: The invited speaker for LDTA 2007 is Uwe Assmann from TU Dresden. Important Dates: - Submission deadline: December 4, 2006 (title and abstract) December 11, 2006 (paper) - Notification: January 16, 2007 - Final version due: February 16, 2007 - Workshop: March 25, 2007 Submission Procedure and Publication: Submission will be open from autumn 2006. Three classes of papers are solicited: research papers, experience reports and short tool-demo papers. Experience reports must describe the use of a language-based tool to solve a non-trivial applied problem with an emphasis on the advantages and disadvantages of the tool. Tool-demo papers should contain a brief description of the tool and include a section that clearly explains what will be demonstrated. Research papers and experience reports should be at most 15 pages in length and tool-demo papers should be at most 4 pages in length. All classes of paper should be submitted electronically as PostScript or PDF files to both of the program committee chairs, Tony Sloane at asloane(a)ics.mq.edu.au and Adrian Johnstone at adrian(a)cs.rhul.ac.uk. The message should also contain a text-only abstract and contact author information. Additional submission details, along with LaTeX style files, are available on the LDTA 2007 web page: http://www.di.uminho.pt/ldta07. The final versions of accepted papers will be published in Electronic Notes in Theoretical Computer Science (ENTCS), Elsevier Science, and will be made available during the workshop. The authors of the best full-length papers will be invited to write a journal version of their paper which will be separately reviewed and, assuming acceptance, be published in journal form. As in past years, this will be done in a a special issue devoted to LDTA 2007 of the journal Science of Computer Programming (Elsevier Science). Program Committee: - Judith Bishop, University of Pretoria, South Africa - Claus Brabrand, BRICS, University of Aarhus, Denmark - Nigel Horspool, University of Victoria, Canada - Johan Jeuring, Utrecht University, The Netherlands - Adrian Johnstone, Royal Holloway, University of London, UK (co-chair), adrian(a)cs.rhul.ac.uk - Steven Klusener, Vrije Universiteit, The Netherlands - Kent Lee, Luther College, USA - Brian Malloy, Clemson University, USA - Terence Parr, University of San Francisco, USA - Michael Schwartzbach, BRICS, University of Aarhus, Denmark - Tony Sloane, Macquarie University, Australia (co-chair), asloane(a)ics.mq.edu.au - Jurgen Vinju, CWI, The Netherlands Organizing Committee: - Thomas Noll, RWTH Aachen University, Germany, noll(a)cs.rwth-aachen.de - Alcino Cunha, University of Minho, Braga, Portugal, alcino(a)di.uminho.pt

1 0

PLAN-X 2007: Call for Participation
by Torsten Grust 29 Nov '06

29 Nov '06

Call for Participation P L A N - X 2 0 0 7 Programming Language Technologies for XML An ACM SIGPLAN Workshop collocated with POPL 2007 Nice, France -- January 20, 2007 www.plan-x-2007.org Please join us for PLAN-X 2007, the fifth workshop in the PLAN-X series, dedicated to the interaction and integration of programming language technology and the world of XML. The XML data model and its associated languages add interesting twists to programming language practice as well as theory. Just like its four predecessors, the PLAN-X 2007 workshop turns the spotlight on how programming language technology can embrace and explain streaming XML transformations, types for XPath and XML updates, web service contracts, tree patterns in XQuery, LINQ and XML Schema, and more. PLAN-X 2007 will feature eight talks, three system demonstrations, extensive opportunity for discussion, and a keynote address (speaker to be announced). PLAN-X 2007 will be held in the Plaza Hotel (Nice, France) all-day on Saturday, January 20, 2007, just after and collocated with POPL 2007, the ACM SIGPLAN - SIGACT Symposium on Principles of Programming Languages (January 17-19, 2007). -- ACCEPTED PAPERS Kazuhiro Inaba, Haruo Hosoya XML Transformation Language Based on Monadic Second Order Logic Nate Foster, Benjamin C. Pierce, Alan Schmitt A Logic Your Typechecker Can Count On: Unordered Tree Types in Practice Alain Frisch, Keisuke Nakano Streaming XML Transformations Using Term Rewriting Giuseppe Castagna, Nils Gesbert, Luca Padovani A Theory of Contracts for Web Services Sebastian Maneth, Helmut Seidl Deciding Equivalences of Top-Down XML Transformations in Polynomial Time Jan Hidders, Philippe Michiels, Jerome Simeon, Roel Vercammen How to Recognise Different Kinds of Tree Patterns From Quite a Long Way Away Pierre Geneves, Nabil Layaida, Alan Schmitt XPath Typing Using a Modal Logic with Converse for Finite Trees James Cheney Lux: A Lightweight, Statically Typed XML Update Language -- ACCEPTED SYSTEM DEMONSTRATIONS Jorge Coelho, Mario Florido XCentric: A Logic-Programming Language for XML Processing Kazuhiro Inaba, Haruo Hosoya MTran: An XML Transformation Language Based on Monadic Second Order Logic Ralf Lämmel LINQ to XSD -- REGISTRATION PLAN-X 2007 is held in cooperation with POPL 2007. You can register for the workshop via the POPL 2007 registration process (online or offline). Please visit http://www.regmaster.com/conf/popl2007.html Registration rates are shown below. The rates are unaffected by the POPL 2007 early bird registration deadline. Note that you can upgrade an existing POPL 2007 registration to include PLAN-X 2007. Workshop-only registration is possible as well. ACM or SIGPLAN Member $89 Non-Member $99 Student $89 Your registration includes a copy of the PLAN-X 2007 informal proceedings, coffee breaks, and lunch. -- PLAN-X 2007 Workshop Chairs - General Chair - Program Chair Torsten Grust Giorgio Ghelli TU München U Pisa Munich, Germany Pisa, Italy grust(a)in.tum.de ghelli(a)di.unipi.it -- PLAN-X 2007 Program Committee - Michael Benedikt (Lucent, USA) - Daniela Florescu (Oracle, USA) - Alain Frisch (INRIA Roquencourt, France) - Giorgio Ghelli, Chair (U Pisa, Italy) - Haruo Hosoya (U Tokyo, Japan) - Anders Møller (U Aarhus, Denmark) - Mukund Raghavachari (IBM T.J. Watson Research Center, USA) - Alan Schmitt (INRIA Rhône-Alpes, France) - Sophie Tison (U Lille, France) - Philip Wadler (U Edinburgh, UK)

1 0

ANN: hpodder 0.99.0
by John Goerzen 28 Nov '06

28 Nov '06

Hi, I'm happy to announce hpodder 0.99.0, the first beta candidate for making an eventual 1.0.0 release of hpodder. hpodder is a podcast downloader that happens to be written in Haskell. This version introduces two major new features: nicer apt-like output and multithreaded downloading. You can download it from http://quux.org/devel/hpodder Thanks, -- John Goerzen Author, Foundations of Python Network Programming http://www.amazon.com/exec/obidos/tg/detail/-/1590593715

1 0

ANN: MissingH 0.16.3
by John Goerzen 28 Nov '06

28 Nov '06

Hello, I am happy to annouce the release of MissingH 0.16.3. The changes in this version include: * New module MissingH.ProgressTracker which tracks the progress of long-running tasks. It can also give estimated time to completion and overall speed statistics, as well as support dividing a task into many subtasks. * New module MissingH.ProgressMeter which displays one or more ProgressTrackers as a status bar on a console. * New module MissingH.Quantity which renders numbers according to a quantification system such as SI or binary * New functions forkRawSystem and pOpen3Raw in MissingH.Cmd. Instead of taking functions to run as actions, instead returns the PID of the child process and leaves it up to the programmer to properly handle the result. As usual, you may download it from http://quux.org/devel/missingh This will be the last release of MissingH as we know it. See the discussion in -cafe for details. The next release will feature major modules split off, and the start of the effort to integrate smaller features into the base Haskell libraries. It will likely also have a new name. -- John

1 0

SimonPJ and Tim Harris explain STM - video
by Bayley, Alistair 28 Nov '06

28 Nov '06

http://channel9.msdn.com/Showpost.aspx?postid=231495 The links to the video are a couple of yellow buttons at the bottom of the article: "Watch" or "Download". I haven't watched this yet (it's nearly an hour long, I think). Found via reddit (http://reddit.com) Haskeller's on TV (sort of...) woot woot! Alistair ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************

7 7