December 2011 - Haskell-Cafe

FLOPS 2012: final call for papers & deadline extension
by Tom Schrijvers 05 Dec '11

05 Dec '11

Final Call For Papers ===================== _EXTENDED SUBMISSION DEADLINE : December 16, 2011_ *Eleventh International Symposium on Functional and Logic Programming (FLOPS 2012)* May 23-25, 2012 Kobe, Japan [http://www.org.kobe-u.ac.jp/flops2012/] FLOPS is a forum for research on all issues concerning declarative programming, including functional programming and logic programming, and aims to promote cross-fertilization and integration between the two paradigms. Previous FLOPS meetings were held in Fuji Susono (1995), Shonan Village (1996), Kyoto (1998), Tsukuba (1999), Tokyo (2001), Aizu (2002), Nara (2004), Fuji Susono (2006), Ise (2008), and Sendai (2010). Topics ====== FLOPS solicits original papers in all areas of functional and logic programming, including (but not limited to): - Declarative Pearls: new and excellent declarative programs with illustrative applications. - Language issues: language design and constructs, programming methodology, integration of paradigms, interfacing with other languages, type systems, constraints, concurrency and distributed computing. - Foundations: logic and semantics, rewrite systems and narrowing, type theory, proof systems. - Implementation issues: compilation techniques, memory management, program analysis and transformation, partial evaluation, parallelism. - Applications: case studies, real-world applications, graphical user interfaces, Internet applications, XML, databases, formal methods and model checking. The proceedings will be published as an LNCS volume. The proceedings of the previous meeting (FLOPS 2010) were published as LNCS 6009. PC co-Chairs ============ - Tom Schrijvers (Ghent University, Belgium) - Peter Thiemann (University of Freiburg, Germany) PC Members ========== - Salvador Abreu (University of Evora, Portugal) - Thorsten Altenkirch (University of Nottingham, UK) - Sebastian Brand (NICTA, Australia) - Giuseppe Castagna (CNRS Univ Paris 7, France) - Sebastian Fischer (Germany) - Marco Gavanelli (University of Ferrara, Italy) - Joxan Jaffar (National University of Singapore, Singapore) - Barry Jay (University of Sydney, Australia) - Andy King (University of Kent, UK) - Claude Kirchner (INRIA, France) - Neelakantan R. Krishnaswami (Microsoft Cambridge, UK) - Yulya Lierler (University of Kentucky, USA) - Keiko Nakata (Tallinn University of Technology, Estonia) - Peter Schneider-Kamp (University of Southern Denmark, Denmark) - Olin Shivers (Northeastern University, USA) - Paul Tarau (University of Northern Texas, USA) - Kazunori Ueda (Waseda University, Japan) - Meng Wang (Chalmers Technical University, Sweden) General Chair and Local co-Chairs ================================= - Naoyuki Tamura (Kobe University, Japan) - Mutsunori Banbara (Kobe University, Japan) - Katsutoshi Hirayama (Kobe University, Japan) Submission ========== Submissions must be unpublished and not submitted for publication elsewhere. Work that already appeared in unpublished or informally published workshops proceedings may be submitted. Submissions should fall into one of the following categories: - Regular research papers: they should describe new results and will be judged on originality, correctness, and significance. - System descriptions: they should contain a link to a working system and will be judged on originality, usefulness, and design. Submissions must be written in English and can be up to 15 pages long, though pearls are typically considerably shorter. Authors are required to use LaTeX2e and the Springer llncs class file, available at [http://www.springer.de/comp/lncs/authors.html] Regular research papers should be supported by proofs and/or experimental results. In case of lack of space, this supporting information should be made accessible otherwise (e.g., a link to a web page, or an appendix). Papers should be submitted electronically at [https://www.easychair.org/conferences/?conf=flops2012] Important Dates =============== - Submission deadline : December 16, 2011 (EXTENDED) - Author notification : February 3, 2012 - Camera-ready copy : March 2, 2012 Place and Related Events ======================== Takikawa Memorial Hall, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 Japan. The 23rd International Conference on Rewriting Techniques and Applications (RTA 2012) and satellite workshops including WFLP 2012 will be held in the week after FLOPS at Nagoya, Japan. Some Previous FLOPS =================== - FLOPS 2010, Sendai: [http://www.kb.ecei.tohoku.ac.jp/flops2010/] - FLOPS 2008, Ise: [http://www.math.nagoya-u.ac.jp/~garrigue/FLOPS2008/] - FLOPS 2006, Fuji Susono: [http://hagi.is.s.u-tokyo.ac.jp/FLOPS2006/] Sponsors ======== - Japan Society for Software Science and Technology (JSSST) SIGPPL In Cooperation with =================== - ACM SIGPLAN - Asian Association for Foundation of Software (AAFS) - Association for Logic Programming (ALP)

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Re: [Haskell-cafe] How to get a file path to the program invoked?
by dokondr 05 Dec '11

05 Dec '11

This is how I finally solved this problem for POSIX complaint system: -- -- TestRun -- module Main where import System.Cmd (rawSystem) import System.Directory (getCurrentDirectory) import System.Environment.Executable (ScriptPath(..), getScriptPath) import System.FilePath.Posix (splitFileName) main = do path <- getMyPath putStrLn $ "myPath = " ++ path let cmdLine = path ++ "args.sh" rawSystem cmdLine ["iphone", "test-twitts.txt"] {-- data ScriptPath Source Constructors: Executable FilePath it was (probably) a proper compiled executable RunGHC FilePath it was a script run by runghc/runhaskell Interactive we are in GHCi --} getMyPath = do curDir <- getCurrentDirectory -- from System.Directory scriptPath <- getScriptPath -- from System.Environment.Executable let path = getMyPath' scriptPath curDir return path getMyPath' (Executable path) _ = fst (splitFileName path) getMyPath' (RunGHC path) _ = fst (splitFileName path) getMyPath' Interactive curDir = curDir++"/" -- All the best, Dmitri O. Kondratiev "This is what keeps me going: discovery" dokondr(a)gmail.com http://sites.google.com/site/dokondr/welcome

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Anonymous, Unique Types, maybe
by Scott Lawrence 04 Dec '11

04 Dec '11

(Sorry if this email is rather unclear - I know my desired end result, but neither how to acheive nor explain it well. Here goes.) I'm processing lists, using them sortof as streams. (Whether that's a good idea isn't the issue here - but let me know if it isn't!) Fundamentally, there are two types of operations (at least, that are relevant here) - those that change the length of the list and those that don't. Some operators might take more than one list/stream as an argument, combining them in some way or another. Obviously, if the lists were different lengths, the operator would fail. I don't want that to happen at run time, so I want to check for it statically, presumably via the type system. I could do this manually: type AList = [Event] type BList = [Event] type CList = [Event] myMapish :: AList -> AList mySelect :: AList -> (Event -> Bool) -> BList myOtherSelect :: BList -> CList but I'd rather not have to manually define a new type for every new list length: myMapish :: List a -> List a mySelect :: List a -> List ? The '?' would be an anonymous, unique type - unless there's a better way to accomplish this. Hope that was clear, and thanks (as always) for the help (and being awesome). -- Scott Lawrence

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ismzero operator possible without equal constraint
by edgar klerks 04 Dec '11

04 Dec '11

Hi list, I am using MonadSplit (from http://www.haskell.org/haskellwiki/New_monads/MonadSplit ) for a project and now I want to make a library out of it. This seems to be straightforward, but I got stuck when I tried to move miszero out of the class: miszero :: m a -> Bool It tests if the provided monad instance is empty. My naive attempt was: miszero :: (Eq (m a), MonadPlus m) => m a -> Bool miszero = ( == mzero ) This works, but not correctly. It adds an Eq constraint that is unneeded. I would prefer to have something like: miszero :: MonadPlus m => m a -> Bool Because I am not comparing the contents of the monad. I don't even touch it. Is this possible to write? with kind regards, Edgar

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ANNOUNCE: Haskell Communities and Activities Report (21st ed., November 2011)
by Janis Voigtländer 04 Dec '11

04 Dec '11

On behalf of all the contributors, I am pleased to announce that the Haskell Communities and Activities Report (21st edition, November 2011) is now available in PDF and HTML formats: http://haskell.org/communities/11-2011/report.pdf http://haskell.org/communities/11-2011/html/report.html 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 I did. If you have not 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 sometimes 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 I 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 2012: target deadline for contributions to the May 2012 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 April (you could point me to them as well, and I 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! Janis Voigtlaender <hcar at haskell.org>

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Weird interaction between literate haskell, ghci and OverloadedStrings
by Erik de Castro Lopo 03 Dec '11

03 Dec '11

Hi, I'm working on a literate haskell document (actually TeX, but the example below is just test) and I'm using ByteStrings in the code. I know I can do: ghci -XOverloadedStrings file.lhs or, after ghci is running I can do: Main> :set -XOverloadedStrings but I'd like to embed a directive in the file so that when loaded in GHCi, I will automatically get OverloadedStrings. This is mainly so that it JustWorks(tm) when I pass the file on to someone else. Is there a way to do this? There is a short example file below. I'm using ghc-7.0.4 from Debian testing. Cheers, Erik ----------8<----------8<----------8<----------8<---------- > {-# LANGUAGE OverloadedStrings #-} This is just text that that ghc/ghci should ignore > import Data.ByteString (ByteString) > import qualified Data.ByteString.Char8 as BS Simple function: > newlineCount :: ByteString -> Int > newlineCount bs = BS.foldl foldFun 0 bs > where foldFun s ch = if ch == '\n' then s + 1 else s Once this file is loaded, I should be able to do this: newlineCount "abcd\ncdead\nasdasd\n" ----------8<----------8<----------8<----------8<---------- -- ---------------------------------------------------------------------- Erik de Castro Lopo http://www.mega-nerd.com/

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cabal install --hyperlink-source ?
by Johannes Waldmann 02 Dec '11

02 Dec '11

Hello. I can do "cabal install --enable-documentation" which is nice because it does configure, build, haddock and copy in one go, but I don't see how to pass options from "cabal install" to "cabal haddock" (e.g., --hyperlink-source) Any hints appreciated, J.W.

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exhibit space at CeBIT Open Source 2012
by Mathias Huber 02 Dec '11

02 Dec '11

Dear Haskellers, this might interest those not too far from Hannover, Germany: http://www.linux-magazine.com/Online/News/CeBIT-Open-Source-2012-Call-for-P… "CeBIT welcomes open source projects to Hannover, Germany! The show organization and Linux Magazine are calling for open source projects to apply for free exhibit space at CeBIT Open Source 2012." There is also a call for papers: http://www.linux-magazine.com/Online/News/CeBIT-2012-Call-for-Papers-Open-S… Best, Mathias

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Program used for debugging
by Yves Parès 02 Dec '11

02 Dec '11

Hey, What do you mostly use for debugging? Simple calls to Debug.Trace.trace? Hpc? Hood?

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PLPV 2012: Call for participation
by Nikhil Swamy 01 Dec '11

01 Dec '11

Call for Participation ====================== PLPV 2012 The Sixth ACM SIGPLAN Workshop Programming Languages meets Program Verification 24th January, 2012 Philadelphia, USA (Affiliated with POPL 2012) http://research.microsoft.com/en-us/um/people/nswamy/plpv12 You are cordially invited to PLPV 2012. 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 or extended static checking systems which incorporate contracts with either static or dynamic contract checking. Registration ============ To register for PLPV 2012, please follow the instructions at: https://regmaster3.com/2012conf/POPL12/register.php The early registration deadline is December 24, 2011. Hotel Information ================= PLPV will be co-located with POPL at the Sheraton Society Hill Hotel in Philadelphia. Please visit POPL's web site to make reservations at the special conference rate. Program ======= Session 1: 9:00am-10:00am LTL types FRP: Linear-time Temporal Logic Propositions as Types, Proofs as Functional Reactive Programs Alan Jeffrey A Hoare Calculus for the Verification of Synchronous Languages Manuel Gesell and Klaus Schneider Session 2: 10:30am-12:00pm Invited talk: Could We Verify an Information-flow Computer? Benjamin C. Pierce University of Pennsylvania Lunch: 12:00pm-2:00pm (not provided) Session 3: 2:00pm-3:30pm Reflexive Toolbox for Regular Expression Matching Vladimir Komendantsky Formal Network Packet Processing with Minimal Fuss: Invertible Syntax Descriptions at Work Reynald Affeldt, David Nowak and Yutaka Oiwa The VerCors project - setting up basecamp Afshin Amighi, Stefan Blom, Marieke Huisman and Marina Zaharieva-Stojanovski Session 4: 4:00pm-5:00pm Dependent Interoperability Peter-Michael Osera, Vilhelm Sjoberg and Steve Zdancewic. Equational Reasoning about Programs with General Recursion and Call-by-value Semantics Garrin Kimmell, Aaron Stump, Harley Eades, Peng Fu, Tim Sheard, Stephanie Weirich, Chris Casinghino, Vilhelm Sjoberg, Nathan Collins and Ki Yung Ahn

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