June 2006 - Haskell - Haskell.org

STM applications and examples?
by Simon Marlow 15 Jun '06

15 Jun '06

Hi Folks, I'm interested in gathering information about existing STM applications and example code that people might be working on or have lying around. It would be great to maintain a list of such applications and example code on the wiki somewhere, and use it as a resource for learning STM and research into STM implementations. If you have an application using STM, please let us know. If you can supply the code, even better. Similarly if you have some STM code that might be suitable as samples or benchmarks, we'd love to collect it. Thanks! Simon

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Announce: Lambdabot 4.0
by dons＠cse.unsw.edu.au 15 Jun '06

15 Jun '06

I'm pleased to announce the release of lambdabot 4.0! lambdabot is a stable, feature rich IRC bot based on a plugin framework. lambdabot 4.0 comes with a suite of more than 50 plugins, including: * a Haskell 98 interpreter * two lambda calculus interpreters * an unlambda interpreter * a pointfree code refactorer * Hoogle support * support for the djinn haskell code generator/theorem prover * a Haskell type and kind inference * typeclass instance lookup * Haskell library search tool * online help * channel logging * a generic search interface, support google, wikipedia and the haskell wiki * a babel language translator * darcs patch tracking * offline mode, editor support * and much more Over the last 14 months work on lambdabot has continued, with help from the #haskell irc community. Over this period, more than 550 patches have been contributed, from 22 developers. The lambdabot code base is now over the 10k lines of code mark! Some of the new features in this release include: * Offline mode! Lambdabot can be used as a command line tool, or from within and editor, to process Haskell source. * Evaluate Bird-style literate haskell directly in channel * Hoogle plugin * Log plugin * Vote plugin, for conduncting online polls * Darcs patch watch plugin * Where plugin, a database of haskell project urls * Code plugin. quote random code from $fptools * Elite plugin, for producing 1337$p33k * Url plugin, print titles of urls posted in channel * Tell plugin, post and retrive messages for users * Local time plugin, report a user's local time * Djinn plugin, for Lennart's Djinn tool * Pretty plugin, for pretty-printing haskell fragments * Compose plugin, a meta-plugin for dynamic composition of other plugins * LambdaShell plugin, another lambda calculus interpreter * Unlambda plugin, an interpreter for unlambda written in Haskell * Gwiki plugin searches the haskell wiki * Hylo plugin, for generating hylomorphisms using the UMinho DrHylo tool * Instances plugin, to find instances for typeclasses As well as: * A new `contextual' plugin system, where plugins can perform arbitrary transformations on the channel stream. * Cabal build system * Flood protection * Start on XMPP support * Improved memory usage, using ByteString and Binary serialised state * More stable. * Much refactoring lambdabot is available via darcs: darcs get --partial http://www.cse.unsw.edu.au/~dons/lambdabot More details are at: http://www.cse.unsw.edu.au/~dons/lambdabot.html -- Don Stewart

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Call For Papers: TACAS 2007
by Grumberg + Huth 14 Jun '06

14 Jun '06

CALL FOR PAPERS: TACAS 2007 Thirteenth International Conference on Tools and Algorithms for the Construction and Analysis of Systems www.doc.ic.ac.uk/tacas07/ Part of ETAPS 2007, March 24 - April 1, 2007, Braga, Portugal IMPORTANT DATES * 6 Oct 2006: Submission deadline (strict) for abstracts of research and tool demonstration papers * 13 Oct 2006: Submission deadline (strict) for full versions of research and tool demonstration papers * 8 Dec 2006: Notification of acceptance * 5 Jan 2007: Camera-ready versions due CONFERENCE DESCRIPTION TACAS is a forum for researchers, developers and users interested in rigorously based tools and algorithms for the construction and analysis of systems. The conference serves to bridge the gaps between different communities that share common interests in, and techniques for, tool development and its algorithmic foundations. The research areas covered by such communities include but are not limited to formal methods, software and hardware verification, static analysis, programming languages, software engineering, real-time systems, communications protocols, and biological systems. The TACAS forum provides a venue for such communities at which common problems, heuristics, algorithms, data structures and methodologies can be discussed and explored. In doing so, TACAS aims to support researchers in their quest to improve the utility, reliability, flexibility and efficiency of tools and algorithms for building systems. Tool descriptions and case studies with a conceptual message, as well as theoretical papers with clear relevance for tool construction are all encouraged. The specific topics covered by the conference include, but are not limited to, the following: * Specification and verification techniques for finite and infinite-state systems * Software and hardware verification * Theorem-proving and model-checking * System construction and transformation techniques * Static and run-time analysis * Abstraction techniques for modeling and validation * Compositional and refinement-based methodologies * Testing and test-case generation * Analytical techniques for secure, real-time, hybrid, critical, biological or dependable systems * Integration of formal methods and static analysis in high-level hardware design or software environments * Tool environments and tool architectures * SAT solvers * Applications and case studies As TACAS addresses a heterogeneous audience, potential authors are strongly encouraged to write about their ideas and findings in general and jargon- independent, rather than in application- and domain-specific, terms. Authors reporting on tools or case studies are strongly encouraged to indicate how their experimental results can be reproduced and confirmed independently. PROGRAMME COMMITTEE Christel Baier (U. Bonn, Germany) Armin Biere (Johannes Kepler U., Austria) Jonathan Billington (University of South Australia, Australia) Ed Brinksma (ESI and U. of Twente, The Netherlands) Rance Cleaveland (U. of Maryland & Fraunhofer USA Inc, USA) Byron Cook (tool chair) (Microsoft Research, Cambridge, UK) Dennis Dams (Bell Labs, Lucent Technologies, Murray Hill, USA) Marsha Chechik (U. Toronto, Canada) Francois Fages (INRIA Rocquencourt, France) Kathi Fisler (Worcester Polytechnic, USA) Limor Fix (Intel Research Laboratory, Pittsburgh, USA) Hubert Garavel (INRIA Rhones-Alpes, France) Susanne Graf (VERIMAG, Grenoble, France) Orna Grumberg (co-chair) (TECHNION, Israel Institute of Technology, Israel) John Hatcliff (Kansas State U., USA) Holger Hermanns (U. des Saarlandes, Germany) Michael Huth (co-chair) (Imperial College London, UK) Daniel Jackson (Massachusetts Institute of Technology, USA) Somesh Jha (U. of Wisconsin at Madison, USA) Orna Kupferman (Hebrew U., Jerusalem, Israel) Marta Kwiatkowska (U. of Birmingham, UK) Kim Larsen (Aalborg U., Denmark) Michael Leuschel (Heinrich-Heine U., Duesseldorf, Germany) Andreas Podelski (Max-Planck-Institut fuer Informatik, Saarbruecken, Germany) Tiziana Margaria-Steffen (U. Goettingen, Germany) Tom Melham (Oxford U., UK) CR Ramakrishnan (SUNY Stony Brook, USA) Jakob Rehof (Fraunhofer ISST, Germany) Natarajan Shankar (SRI, Menlo Park, USA) Bernhard Steffen (U. Dortmund, Germany) Lenore Zuck (U. of Illinois, USA). INVITED SPEAKER K. Rustan M. Leino (Microsoft Research, USA) SUBMISSION GUIDELINES Papers should be submitted using the TACAS 2007 Conference Service. As with other ETAPS conferences, TACAS accepts two types of contributions: * research papers and * tool demonstration papers. Both types of contributions will appear in the proceedings and have oral presentations during the conference. Research papers: Research papers cover one or more of the topics above, including tool development and case studies from a perspective of scientific research. Research papers are evaluated by the TACAS Program Committee. Submitted research papers must: * be in English and have a maximum of 15 pages (including figures and bibliography) * present original research which is unpublished and not submitted elsewhere (conferences or journals) -- in particular, simultaneous submission of the same contribution to multiple ETAPS conferences is forbidden * use the Springer-LNCS style * be submitted electronically in Postscript or PDF form via the TACAS 2007 Conference Service (abstract no later than 6 October, 2006, and full paper no later than 13 October, 2006) Submissions deviating from these instructions may be rejected without review. Any questions regarding this policy should be directed to the Program Committee Co-Chairs Orna Grumberg (www.cs.technion.ac.il/users/orna/) or Michael Huth (www.doc.ic.ac.uk/~mrh/) prior to submitting. Tool demonstration papers: Tool demonstration papers present tools based on aforementioned technologies (e.g., theorem-proving, model-checking, static analysis, or other formal methods) or fall into the above application areas (e.g., system construction and transformation, testing, analysis of real-time, hybrid or biological systems, etc.). Tool demonstration papers are evaluated by the TACAS Tool Chair, Byron Cook (http://research.microsoft.com/users/bycook/default.htm) with the help of the Programme Committee. Submitted tool demonstration papers must: * be in English and have a maximum of 4 pages * have an appendix (not included in the 4 page count) that provides a detailed description of: - how the oral presentation will be conducted, e.g. illustrated by a number of snapshots - the availability of the tool, the number and types of users, other information which may illustrate the maturity and robustness of the tool - if applicable, a link to a web-page for the tool (The appendix will not be included in the proceedings, but during the evaluation of the tool demonstration papers it will be equally important as the pages submitted for publication in the proceedings.) * use the Springer-Verlag LNCS style * clearly describe the enhancements and novel features of the tool in case that one of its previous versions has already been presented at meetings or published in some form * be submitted electronically in Postscript or PDF form via the TACAS 2007 Conference Service (abstract no later than 6 October, 2006, and full paper no later than 13 October, 2006) Submissions deviating from these instructions may be rejected without review. Any questions regarding this policy should be directed to the Tool Chair Byron Cook.

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ANN: HSH (Haskell Shell) 0.1.0
by John Goerzen 09 Jun '06

09 Jun '06

Hello, Following the "release early, release often" motto, I am happy to announce version 0.1.0 of HSH, the Haskell shell. You may obtain it with: darcs get --tag 0.1.0 http://darcs.complete.org/hsh Things are still very rough in many ways, but this version already lets you: * Run commands * Pipe things between commands * Pipe command input/output into and out of pure Haskell functions * Pure Haskell functions are as much a first-class citizen as is grep or cat Here is an example session: $ ghci -fglasgow-exts HSH *HSH> run $ ("ls", ["."]) COPYING HSH HSH.hs TODO announcements testsrc COPYRIGHT HSH.cabal Makefile _darcs test.hs *HSH> run $ ("ls", ["-l"]) -|- ("wc", ["-l"]) 12 *HSH> :m +Text.Printf *HSH Text.Printf> let countLines = (zipWith (\i line -> printf "%-5d %s" i line) [(1::Int)..])::([String] -> [String]) *HSH Text.Printf> run $ ("ls", ["-l"]) -|- countLines -|- ("grep", ["hs$"]) 6 -rw-r--r-- 1 jgoerzen jgoerzen 1285 Jun 6 09:43 HSH.hs 11 -rw-r--r-- 1 jgoerzen jgoerzen 565 Jun 6 09:43 test.hs *HSH Text.Printf> :m +Data.List *HSH Text.Printf Data.List> run $ ("ls", ["-l"]) -|- countLines -|- filter (isSuffixOf "hs") 6 -rw-r--r-- 1 jgoerzen jgoerzen 1285 Jun 6 09:43 HSH.hs 11 -rw-r--r-- 1 jgoerzen jgoerzen 565 Jun 6 09:43 test.hs *HSH Text.Printf Data.List> run $ ("ls", ["-l"]) -|- countLines -|- filter (isSuffixOf "hs") -|- ("tr", ["a-z", "A-Z"]) 6 -RW-R--R-- 1 JGOERZEN JGOERZEN 1285 JUN 6 09:43 HSH.HS 11 -RW-R--R-- 1 JGOERZEN JGOERZEN 565 JUN 6 09:43 TEST.HS *HSH Text.Printf Data.List> let generator = \(_::String) -> unlines . map show $ [1..20] *HSH Text.Printf Data.List> generator "" "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n" *HSH Text.Printf Data.List> run $ generator -|- ("grep", ["1"]) 1 10 11 12 13 14 15 16 17 18 19 Future versions will likely simplify syntax to make it easier to write scripts and introduce a sh to hsh converter. I also plan to add pure Haskell tools for some common shell-ish things that one could do in Haskell. -- John

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ANN: VersionTool 1.0
by Manuel M T Chakravarty 08 Jun '06

08 Jun '06

I like to announce a tiny tool that * extracts version information from Cabal files, * maintains version tags in darcs, * computes patch levels by querying darcs, * extracts the current context from darcs, and * adds all this information to a source file (eg, for printing with --version and --exact-version type of options). More at http://www.cse.unsw.edu.au/~chak/haskell/VersionTool/ Happy Hacking! Manuel

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STM Monad Transformer
by Thomas Conway 08 Jun '06

08 Jun '06

Hi All, I'm not quite sure I've even got the question right, but here goes anyway.... I am using STM for a concurrent BTree implementation. My plan is to have a cache of file pages that have been read from disk. A "pointer" within the BTree will either dereference to a page address for a page that has not been read in, or the in-memory representation for a page that has been read. Clear as mud? Consider the following prototypical definitions: data Node k v = Leaf [(k,v)] | Node [(k,NodePtr k v)] type NodePtr k v = TVar (Either Int (Node k v)) where the Int is a file offset, or page number, or somesuch. If an attempt is made during a STM transaction to access a page that is not in memory, I'd like the transaction to "abort" and return the address of the page so that it can be read from disk and the transaction retried. Now, the code is going to contain quite a frew fragments like the following: insert p k v = do n <- getNode p case n of Leaf ... -> I think I want the type of insert to be insert :: NodePtr k v -> k -> v -> Either (STM ()) Int that is, either I get back the transaction, or the page address. The question is, how do I combine the two monads STM and Either to achieve this cleanly? I've tried reading a few pages about monad transformers, but it is not evident to me yet how to combine the two. I think it calls for STMT (following the FooT naming convention). Any astute observations welcome, Tom

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CFP: WORLDCOMP'06
by Marco Morazan 08 Jun '06

08 Jun '06

Call For Participation The 2006 World Congress in Computer Science, Computer Engineering, and Applied Computing WORLDCOMP'06 June 26-29, 2006, Las Vegas, USA Academic Co-sponsors: Massachusetts Institute of Technology's (MIT) Media Lab; Texas Advanced Computer Center (TACC) of University of Texas at Austin; and others. You are invited to participate in WORLDCOMP'06 congress. The congress will be held at Monte Carlo Resort, Las Vegas, USA, June 26-29, 2006. The event is composed of 24+4 tracks (includes over 150 sessions/workshops), a number of keynote lectures, invited talks, tutorials, and panel discussions. The main tracks are listed below: o Conference on Parallel & Distributed Processing Techniques & Applications (PDPTA'06) + Real-Time Computing Systems & Applications (RTCOMP) o Conference on Scientific Computing (CSC'06) o Conference on Grid Computing & Applications (GCA'06) o Conference on Security & Management (SAM'06) o Conference on Artificial Intelligence (ICAI'06) o Conference on Machine Learning; Models, Technologies & Applications (MLMTA'06) o Conference on Software Engineering Research & Practice (SERP'06) o Conference on Programming Languages & Compilers (PLC'06) o Conference on Internet Computing (ICOMP'06) + Semantic Web & Web Services (SWWS'06) + Computer Games Development (CGD'06) o Conference on Computer Design (CDES'06) + Computing in Nanotechnology (CNAN'06) o Conference on Embedded Systems & Applications (ESA'06) o Conference on Wireless Networks (ICWN'06) o Conference on Pervasive Systems & Computing (PSC'06) o Conference on Image Processing, Computer Vision, & Pattern Recognition (IPCV'06) o Conference on Computer Graphics & Virtual Reality (CGVR'06) o Conference on Modeling, Simulation & Visualization Methods (MSV'06) o Conference on Frontiers in Education: Computer Science & Computer Engineering (FECS'06) o Conference on Foundations of Computer Science (FCS'06) o Conference on e-Learning, e-Business, Enterprise Information Systems, e-Government, & Outsourcing (EEE'06) o Conference on Data Mining (DMIN'06) o Conference on Information & Knowledge Engineering (IKE'06) o Conference on Bioinformatics & Computational Biology (BIOCOMP'06) o Conference on Engineering of Reconfigurable Systems & Algorithms (ERSA'06) o Conference on Communications in Computing (CIC'6) Registration information can be found at: http://www.world-academy-of-science.org/worldcomp06/ws/Registration Hotel information can be found at: http://www.world-academy-of-science.org/worldcomp06/ws/Location WORLDCOMP'06 programs/schedules can be found at: http://www.world-academy-of-science.org/worldcomp06/ws/Program General information about the congress can be found at: http://www.world-academy-of-science.org/worldcomp06/ws/index_html

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CFP: APLAS 2006
by Eijiro Sumii 08 Jun '06

08 Jun '06

[sending on behalf of the program chair] **************************************************** *** The deadline of abstract submission: June 2 *** *** The deadline of paper submission: June 6 *** **************************************************** CALL FOR PAPERS The Fourth ASIAN Symposium on Programming Languages and Systems (APLAS 2006) Sydney, Australia, November 8-10, 2006 http://www.kb.ecei.tohoku.ac.jp/aplas2006/ APLAS aims at stimulating programming language research by providing a forum for the presentation of recent results and the exchange of ideas and experience in topics concerned with programming languages and systems. APLAS is based in Asia, but is an international forum that serves the worldwide programming languages community. The APLAS series is sponsored by the Asian Association for Foundation of Software (AAFS), which has recently been founded by Asian researchers in cooperation with many researchers from Europe and the USA. The past formal APLAS symposiums were successfully held in Tsukuba (2005, Japan), Taipei (2004, Taiwan) and Beijing (2003, China) after three informal workshops held in Shanghai (2002, China), Daejeon (2001, Korea) and Singapore (2000). Proceedings of the past symposiums were published in Springer-Verlag's LNCS 2895, 3302, and 3780. TOPICS The symposium is devoted to both foundational and practical issues in programming languages and systems. Papers are solicited on, but not limited, to the following topics: * semantics, logics, foundational theory * type systems, language design * program analysis, optimization, transformation * software security, safety, verification * compiler systems, interpreters, abstract machines * domain-specific languages and systems * programming tools and environments Original results that bear on these and related topics are solicited. Papers investigating novel uses and applications of language systems are especially encouraged. Authors concerned about the appropriateness of a topic are welcome to consult with the program chair (koba(a)ecei.tohoku.ac.jp) prior to submission. GENERAL CO-CHAIRS Manuel Chakravarty (University of New South Wales, Australia) Gabriele Keller (University of New South Wales, Australia) PROGRAM CHAIR Naoki Kobayashi (Tohoku University) PROGRAM COMMITTEE Kung Chen (National Chengchi University, Taiwan) Wei-Ngan Chin (National University of Singapore, Singapore) Patrick Cousot (ENS, France) Masahito Hasegawa (Kyoto University, Japan) Jifeng He (United Nations University, Macau) Haruo Hosoya (University of Tokyo, Japan) Bo Huang (Intel China Software Center, China) Naoki Kobayashi (chair) (Tohoku University, Japan) Oege de Moor (Oxford University, UK) George Necula (University of California at Berkeley, USA) Martin Odersky (EPFL, Switzerland) Tamiya Onodera (IBM Research, Tokyo Research Laboratory, Japan) Yunheung Paek (Seoul National University, Korea) Sriram Rajamani (Microsoft Research, USA) Andrei Sabelfeld (Chalmers University of Technology, Sweden) Zhong Shao (Yale University, USA) Harald Sondergaard (University of Melbourne, Australia) Nobuko Yoshida (Imperial College London, UK) INVITED SPEAKERS Jens Palsberg (UCLA, USA) Peter Stuckey (University of Melbourne, Australia) SUBMISSIONS INFORMATION Papers should be submitted electronically online via the conference submission webpage. Acceptable formats are PostScript or PDF, viewable by Ghostview or Acrobat Reader. Submissions should not exceed 16 pages in LNCS format, including bibliography and figures. Submitted papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. They should clearly identify what has been accomplished and why it is significant. Submitted papers must be unpublished and not submitted for publication elsewhere. The proceedings of the symposium will be published as a volume in Springer-Verlag's Lecture Notes in Computer Science series. Authors of accepted papers must provide all the electronic files of the final version of papers according to the instruction provided at the LNCS home page (www.springer.com/lncs) IMPORTANT DATES Abstract Submission: June 2, 2006 Paper Submission: June 6, 2006 Author notification: August 5, 2006 Camera Ready: August 25, 2006 Conference: November 8-10, 2006

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Re: [Haskell] Edison 1.2 and profiling
by Mario Blazevic 05 Jun '06

05 Jun '06

> > > > > Enabling profiling can significantly change the space behavior of > > programs. There may be some important optimizations that don't occur > > in the presence of profiling, and the profiling data itself takes > > some memory. I have to admit, I don't know a lot about GHC profiling > > so I'm afraid I can't be of much help. > > Me neither. I tried several things: Just turning off the optimizations doesn't cause the > problem. Optimization + profiling (-O -prof) has the same problem as -prof alone. It > doesn't matter if -auto-all option is there or not. And the profiled program gobbles up > all memory with or without the +RTS -p option. > Furthermore, the problem has nothing to do with Edison. The version 6.4.2 of ghc is the culprit. I hadn't run the profiler since I upgraded to 6.4.2 until now. But now when I compile with 6.4.2 the old version of the program, using Data.Map, I see the same behavior as with PatriciaLoMap: the program diverges and eats all available memory. I thought it could be the GCC 4.1.1 which was also a recent upgrade, but the behavior is the same with -prof -fasm options. So I guess it must be ghc. Did anybody else encounter this problem?

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Faucet and drain programs no worky
by ihope 04 Jun '06

04 Jun '06

Well, I was needing to make some circular pipelines, so I whipped up a pair of programs called "faucet" and "drain". Stuff would flow into the drain at the end of the pipe, when it comes out of the faucet at the beginning. Here's the drain program: > module Main where > > import Network > import System.IO > import System.Environment(getArgs) > > main = withSocketsDo $ do > input <- getContents > (args:_) <- getArgs > let port = PortNumber (fromInteger (read args)) > sock <- listenOn port > loop sock input > where loop sock input = do (handle, hostname, _) <- accept sock > hSetBuffering handle NoBuffering > if hostname == "localhost" > then hLazyPutStr handle input > else return () > hClose handle > loop sock input > > hLazyPutStr handle = foldr (\x xs -> hPutChar handle x >> xs) (return ()) And the faucet (much simpler, no?): > module Main where > > import Network > import System.IO > import System.Environment(getArgs) > > main = withSocketsDo $ do > (args:_) <- getArgs > let port = PortNumber (fromInteger (read args)) > conn <- connectTo "localhost" port > hGetContents conn >>= putStr The problem: each drain only seems to support one faucet. You only need multiple faucets if you want to branch off and stuff, but I like my programs to be perfect :-) (By the way, the drain should send the entirety of its input to every faucet, no matter when they connect.) The other problem is that the faucet doesn't wait forever for a drain to appear, but I'd like it to. How can I fix these problems? --ihope

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