September 2010 - Haskell

PLPV 2011: Call for papers
by Wouter Swierstra 14 Sep '10

14 Sep '10

-------------------------------------------------------------------------- The Fifth ACM SIGPLAN Workshop on Programming Languages meets Program Verification --------------------------------------------------------------------------- http://cseweb.ucsd.edu/plpv11 --------------------------------------------------------------------------- 29th January, 2011 Austin, Texas Affiliated with POPL 2011 Overview -------- The goal of PLPV is to foster and stimulate research at the intersection of programming languages and program verification, by bringing together experts from diverse areas like types, contracts, interactive theorem proving, model checking and program analysis. Work in this area typically attempts to reduce the burden of program verification by taking advantage of particular semantic or structural properties of the programming language. Examples include dependently typed programming languages, which leverage a language's type system to specify and check richer than usual specifications, possibly with programmer-provided proof terms, extended static checking systems like ESC/Java and Spec#, which incorporate contracts and static contract verifiers. We invite submissions on all aspects, both theoretical and practical, of the integration of programming language and program verification technology. To encourage cross-pollination between different communities, we seek a broad the scope for PLPV. In particular, submissions may have diverse foundations for verification (Type-based, Hoare-logic-based, Abstract Interpretation-based, etc), target different kinds of programming languages (functional, imperative, object-oriented, etc), and apply to diverse kinds of program properties (data structure invariants, security properties, temporal protocols, resource constraints, etc). Important Dates --------------- Submission 11th October, 2010 Notification 8th November, 2010 Final Version 15th November, 2010 Workshop 29th January, 2011 Program Committee ----------------- Andrew Gordon (Microsoft Research) Chris Hawblitzel (Microsoft Research) Ranjit Jhala (University of California, San Diego, co-chair) Viktor Kuncak (Ecole Polytechnique Fédérale de Lausanne) John Matthews (Galois Inc.) James McKinna (Radboud University) Stefan Monnier (Université de Montréal) Greg Morrisett (Harvard University) Christine Paulin-Mohring (Université Paris-Sud) Wouter Swierstra (Radboud University Nijmegen , co-chair) Tachio Terauchi (Tohoku University) Submissions ----------- Submissions should fall into one of the following categories: (a) Research papers (12 pages) that describe new work on the above or related topics. Submissions in this category have an upper limit of 12 pages but shorter submissions are also encouraged. (b) Proposals for challenge problems (6 pages) which the author believes are useful benchmarks or important domains for language-based program verification techniques. Submissions in this category should be at most 6 pages in total length. Submissions should be prepared with SIGPLAN two-column conference format. Submitted papers must adhere to the SIGPLAN republication policy. Concurrent submissions to other workshops, conferences, journals, or similar forums of publication are not allowed. Publication ----------- Accepted papers will be published by the ACM and will appear in the ACM Digital library. The authors of selected papers will be invited to submit an extended version of their paper to a special issue of the Journal of Formalized Reasoning devoted to papers from PLPV 2011. Student Attendees ----------------- Students with accepted papers or posters are encouraged to apply for a SIGPLAN PAC grant that will help to cover travel expenses to PLPV. Details on the PAC program and the application can be found here. PAC also offers support for companion travel.

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Announcement
by Richard 11 Sep '10

11 Sep '10

My book "Pearls of Functional Algorithm Design" will be published by CUP this month. See http://www.comlab.ox.ac.uk/news/237-full.html Richard Bird

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New haskell.org server
by Ian Lynagh 09 Sep '10

09 Sep '10

Hi all, We will shortly be replacing the haskell.org server with a more modern, commercially hosted machine. For now, the new server is available as http://new-www.haskell.org/ The ghc, hugs and nhc98 websites have been copied across, and there is a copy of the wiki (although that will be resynced when we change servers). We will also be moving the mailing lists at changeover time. *** If you know of anything else that haskell.org *** *** does, and should keep doing, please let us know *** *** now or it will break soon! *** *** *** *** If you have anything else on haskell.org, *** *** please find it a new home now! *** Note that if there are other services currently running on haskell.org, this may be a good time to consider moving them to the community server instead: http://community.haskell.org/ Meanwhile, we would like to thank Paul Hudak, John Peterson, Mark Wogahn, the Yale Workstation Support team and Yale University for hosting, running and maintaining the haskell.org server for countless years. We would also like to thank the Haskell Summer of Code team for providing the funding for the new server, and the community sysadmin team for agreeing to maintain it in the future. Thanks also to Thomas Schilling and Ashley Yakeley for getting the wiki up and running, and restyling it. Thanks Ian, on behalf of the Haskell Infrastructure team.

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Proposal: Form a haskell.org committee
by Ian Lynagh 09 Sep '10

09 Sep '10

Dear Haskellers, In recent years, haskell.org has started to receive assets, e.g. money from Google Summer Of Code, donations for Hackathons, and a Sparc machine for use in GHC development. We have also started spending this money: on the community server, on a server to take over hosting haskell.org itself, and on the haskell.org domain name. There is also interest in running fundraising drives for specific things such as Hackathon sponsorship and hosting fees. However, it is not currently clear who is responsible for determining what the haskell.org money should be spent on, or what are and are not acceptable uses of the domain name and hardware. To fix this problem, we propose that we create a "haskell.org committee", which is responsible for answering these sorts of questions, although for some questions they may choose to poll the community at large if they think appropriate. We suggest that the committee be composed of 5 representatives from the community, with committee members standing down after at most 3 years. Each year the committee will appoint one of their members to be the chair. As membership of "the Haskell community" is not well-defined, and voting would potentially be open to abuse if anyone were able to vote, we propose that the committee should choose their replacements from open nominations. Unfortunately, this gives us a bootstrapping problem, so we suggest that the initial committee be chosen from open nominations by some of the people who currently de-facto end up making the decisions currently: Duncan Coutts, Isaac Jones, Ian Lynagh, Don Stewart and Malcolm Wallace. These 5 would still be elligible to nominate themselves. Two of the initial members will stand down after one year, and two after two years, in order to bootstrap rolling membership turnover. We would love to hear feedback from you about this proposal, so that we can see whether the proposal, or something similar, has consensus amongst the community! A related issue is that haskell.org does not currently exist as a legal entity. We also hope to solve that problem, but we are still gathering information so that the community can make an informed decision, so I won't say more about that for now. Thanks Ian

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ANN: iyql - interactive yql
by Diego Souza 09 Sep '10

09 Sep '10

Hi All, I'm pleased to announce iyql, an interactive CLI for YQL [ http://developer.yahoo.com/yql/console] This version provides the first release, which allows you perform all queries supported by YQL [with the sole exception of parenthesis in WHERE clause]. Among other things, completion and history are implemented [=haskeline] along with support for queries that requires OAuth authentication. Plans for next releases: * Implement a decent error handling: currently any unexpected exception aborts the program; * Support parenthesis in WHERE clause; * More local functions; Please let me know about any issues or suggestions! Regards, -- ~dsouza yahoo!im: paravinicius gpg key fingerprint: 71B8 CE21 3A6E F894 5B1B 9ECE F88E 067F E891 651E gpg pub key: http://bitforest.org/~dsouza/pub/gpg-pubkey.txt<http://bitforest.org/%7Edsouza/pub/gpg-pubkey.txt> authorized_keys: http://bitforest.org/~dsouza/pub/authorized_keys.txt<http://bitforest.org/%7Edsouza/pub/authorized_keys.txt>

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Re: [Haskell-cafe] Re: Re: [Haskell] ANNOUNCE: reference 0.1
by Maciej Piechotka 08 Sep '10

08 Sep '10

On Wed, 2010-09-08 at 09:53 +0200, Alberto G. Corona wrote: > Ah, ok. I though that your intention was to restrict the class > definition for the IO monad . Goood. > > > Maybe in the long term, it make sense to include this type class in > some monad related package such is mtl, since references are part of > many user monads. I think also that some default instances can be > defined for transformed monads. > Yes - they can. In fact: instance (MonadTrans t, Monad (t m), Reference r m) => Reference r (t m) where newRef = lift . newRef readRef = lift . readRef writeRef r = lift . writeRef r instance (MonadIO m, Reference r IO) => Reference r m where newRef = liftIO . newRef readRef = liftIO . readRef writeRef r = liftIO . writeRef r > > It is pleasant for me to read and write something like > > > x <- readRef rx > > > rather than > > > x<- readMyMonadRef sx > > > Such generalizatiopns may be also good for extracting more common > patterns among different monads. Actually the primary need was to create mutable single-linked list for iteratee-parsec. I didn't wanted to restrict myself to ST or IO so I choose to add class for them. Regards

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ANNOUNCE: grammar-combinators 0.1 (initial release): A parsing library of context-free grammar combinators
by Dominique Devriese 08 Sep '10

08 Sep '10

The grammar-combinators library is a parsing library employing a novel grammar representation with explicit recursion. The library features much of the power of a parser generator like Happy or ANTLR, but with the library approach and most of the benefits of a parser combinator library. Grammars and grammar algorithms are defined in a functional style. The library currently has the following features: * Grammar specified completely in Haskell using an elegant syntax * Grammar algorithms implemented in a functional style (no fresh identifiers), with elegant and meaningful types. * Multi-backend: use the same grammar with a Packrat, Parsec or UUParse parser * Grammar transformations: use left-recursive grammars directly thanks to a powerful grammar transformation library, featuring the left-corner left-recursion removal transform, a uniform version of the classic Paull left-recursion removal, and various smaller transformations (dead-branch removal, dead non-terminal removal, consecutive epsilon combination, selective unfolding etc.). * Grammar utility functions: printing of grammars, FIRST-set calculation, reachability analysis of non-terminals, etc. * Compile-time transformations (using Template Haskell), given a suitable definition of the grammar. This is currently limited to a certain set of transformations. The library is currently not intended for mainstream use. Its API is relatively stable, but performance needs to be looked at further. We are submitting a paper about the ideas behind this library to PADL 2011. A draft is linked on the project's website. More information: * Project website: http://projects.haskell.org/grammar-combinators/ * Tutorial: http://projects.haskell.org/grammar-combinators/tutorial.html * Hackage: http://hackage.haskell.org/package/grammar-combinators All comments welcome! Dominique PS. The documentation on hackage currently doesn't build because of (seemingly) a Hackage dependency problem during the build [1]. Compiling and generating the documentation locally should work fine. A version of the docs is available on the project's webpage as a temporary replacement [2]. Footnotes: [1] http://www.haskell.org/pipermail/libraries/2010-September/014168.html [2] http://projects.haskell.org/grammar-combinators/docs/index.html

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ANNOUNCE: reference 0.1
by Maciej Piechotka 07 Sep '10

07 Sep '10

Reference is class which generalizes references and monads they exists in. It means that IORef, STRef and others can be accessed by common interface. Currently it is of form: class Reference r m where 1. There was a proposal to rename the class to MonadRef or MonadReference. IMHO it would imply m -> r functional dependency and therefore disallow the instances for both MVar IO and IORef IO 2. Should the functional dependencies or type famillies be introduced? Personally I don't think so as I would like to allow all of the following: - IORef IO - MVar IO - IORef (ContT IO) - MVar (ContT IO) Any feedback mostly welcome. Regards PS. Darcs repository will be available soon

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TLDI 2011: 2nd Call For Papers
by Stephanie Weirich 07 Sep '10

07 Sep '10

TLDI 2011 2nd CALL FOR PAPERS The Sixth ACM SIGPLAN Workshop on Types in Language Design and Implementation Austin, Texas, USA Tuesday, January 25, 2011 (Co-located with POPL 2011) http://www.mpi-sws.org/~dreyer/tldi2011/ Submission Deadline: October 11, 2010 The role of types and proofs in all aspects of language design, compiler construction, and software development has expanded greatly in recent years. Type systems, type-based analyses and type-theoretic deductive systems have been central to advances in compilation techniques for modern programming languages, verification of safety and security properties of programs, program transformation and optimization, and many other areas. The ACM SIGPLAN Workshop on Types in Language Design and Implementation brings researchers together to share new ideas and results concerning all aspects of types and programming, and is now an annual event. TLDI 2011 is the sixth workshop in the series and will be co-located with POPL in Austin, Texas in January 2011. Submissions for TLDI 2011 are invited on all interactions of types with language design, implementation, and programming methodology. This includes both practical applications and theoretical aspects. TLDI 2011 specifically encourages papers from a broad field of programming language and compiler researchers, including those working on object-oriented or dynamic languages, systems programming, mobile-code or security, as well as traditional fully-static type systems. Topics of interest include: * Typed intermediate languages and type-directed compilation * Type-based language support for safety and security * Types for interoperability * Type systems for system programming languages * Type-based program analysis, transformation, and optimization * Dependent types and type-based proof assistants * Types for security protocols, concurrency, and distributed computing * Type inference and type reconstruction * Type-based specifications of data structures and program invariants * Type-based memory management * Proof-carrying code and certifying compilation * Types and objects This is not meant to be an exhaustive list; papers on novel utilizations of type information are welcome. Authors concerned about the suitability of a topic are encouraged to inquire via electronic mail to the program chair prior to submission. Submission Guidelines: Authors should submit a full paper of no more than 12 pages (including bibliography and appendices) by Monday, October 11, 2010. The submission deadline and length limitations are firm. Submissions that do not meet these guidelines will not be considered. All submissions should be in standard ACM SIGPLAN conference format: two columns, nine-point font on a ten-point baseline. Detailed formatting guidelines are available on the SIGPLAN Author Information page, along with a LaTeX class file and template. Papers must be submitted electronically via the workshop website (http://www.mpi-sws.org/~dreyer/tldi2011/) in Adobe Portable Document Format (PDF) and must be formatted for US Letter size (8.5"x11") paper. Authors for whom this is a hardship should contact the program chair before the deadline. Submitted papers must adhere to the SIGPLAN Republication Policy. Submissions should contain original research not published or submitted for publication elsewhere. Publication: As in previous years, accepted papers will be published by the ACM and appear in the ACM digital library. A printed proceedings will be available at the workshop. Important Dates: - Submission deadline: October 11, 2010 (Monday), 21:00 Samoa-Apia Time - Notification: November 8, 2010 (Monday) - Final versions due: November 22, 2010 (Monday) - Workshop: January 25, 2011 (Tuesday) General Chair: Stephanie Weirich University of Pennsylvania sweirich at cis dot upenn dot edu Program Chair: Derek Dreyer Max Planck Institute for Software Systems (MPI-SWS) dreyer at mpi-sws dot org Program Committee: Thorsten Altenkirch (University of Nottingham) Fritz Henglein (University of Copenhagen) Michael Hicks (University of Maryland, College Park) Limin Jia (Carnegie Mellon University) Mark Jones (Portland State University) Neel Krishnaswami (Microsoft Research, Cambridge) Paul-André Melliès (CNRS & Université Paris Diderot) Aleks Nanevski (IMDEA Software, Madrid) Benjamin Pierce (University of Pennsylvania) Tachio Terauchi (Tohoku University) Sam Tobin-Hochstadt (Northeastern University) Steering Committee: Amal Ahmed (Indiana University) Nick Benton (Microsoft Research, Cambridge) Derek Dreyer (MPI-SWS) Robert Harper (Carnegie Mellon University, chair) Andrew Kennedy (Microsoft Research, Cambridge) Francois Pottier (INRIA Rocquencourt) Zhong Shao (Yale University) Stephanie Weirich (University of Pennsylvania)

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ANN: hledger 0.12.1
by Simon Michael 06 Sep '10

06 Sep '10

I'm pleased to announce hledger 0.12.1, with a new web interface and bugfixes. Thanks to Ben Boeckel and David Patrick for their help this time around. Installation docs, linux/mac/windows binaries and more are at http://hledger.org and http://hackage.haskell.org/package/ hledger . Release notes: 2010/9/6 hledger 0.12.1 * web: new, better web ui; accounts are now a permanent sidebar; add form uses auto-completing combo fields * installing: fix a build error with parsec 3 (#22) * installing: require exactly matching hledger-lib version for more robust builds * installing: explicit data-object dependency to ensure hledger and hledger-lib use the same time version * installing: explicit hamlet dependency for more robust building * installing: build threaded and with warnings * installing: drop -fweb610 flag * installing: add gtk2hs-buildtools dependency needed to build with -fchart * installing: require cabal 1.6 or greater * add -D/--daily flag * register: with --depth, clip account names or aggregate postings rather than excluding them * fix !include with deeply nested directories (#21) * fix obscured date parse errors with parsec 3 * handle unicode better in errors * fix a ghc 6.12.3 error when running interpreted Stats: 50 days and 90 commits since last release, now at 5741 lines of code with 136 tests and 41% unit test coverage. Goals for the next release are: 1. implement a plugin mechanism, probably by searching for hledger-* named binaries in $PATH at startup and handing over control. This should make packaging easier and more scalable. 2. move web/vty/chart features into their own packages. 3. developer docs 4. a public project ledger tracking expenses/income/resources Problem reports and all help are welcome; additional bugfix releases will appear on hackage if needed. Best, -Simon

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