February 2006 - Haskell

ICFP 2006 --- Call for Papers
by Simon Marlow 20 Feb '06

20 Feb '06

[posting on behalf of John Reppy <jhr(a)cs.uchicago.edu>] ====================================================================== International Conference on Functional Programming (ICFP 2006) Call for Papers September 18-20, 2006 Portland, Oregon, USA Submission deadline: 7 April, 2006 http://icfp06.cs.uchicago.edu ICFP 2006 seeks original papers on the art and science of functional programming. Submissions are invited on all topics ranging from principles to practice, from foundations to features, from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects and concurrency. Particular topics of interest include: * Applications and domain-specific languages: Systems programming, scientific and numerical computing, symbolic computing and artificial intelligence, databases, graphical user interfaces, multimedia programming, application scripting, system administration, distributed-systems and web programming, XML processing, security. * Foundations: Formal semantics, lambda calculus, type theory, monads, continuations, control, state, effects. * Design: Algorithms and data structures, modules and type systems, concurrency and distribution, components and composition, relations to object-oriented and logic programming. * Implementation: Abstract machines, compile-time and run-time optimization, just-in-time compilers, memory management. Interfaces to foreign functions, services, components and low-level machine resources. * Transformation and analysis: Abstract interpretation, partial evaluation, program transformation. * Software-development techniques for functional programming: Design patterns, specification, verification, validation, debugging, test generation, tracing and profiling. * Practice and experience: Functional programming in education and industry. * Functional pearls: Elegant, instructive examples of functional programming. Papers in the last two categories need not necessarily report original research results; they may instead, for example, report practical experience that will be useful to others, re-usable programming idioms, or elegant new ways of approaching a problem. A special issue of the Journal of Functional Programming will highlight selected papers from the meeting. Submission instructions are available at http://www.easychair.org/ ICFP2006/ The top submitted papers, as determined by the program committee, will be invited to submit journal versions for a special issue of JFP. Important Dates: Submission deadline: 7 April, 2006 On-line response to reviews: 14 May, 2006 Author notification: 273 May, 2006 Camera-ready copy: 26 June, 2006 Organizers: Conference Chair: John Reppy (University of Chicago) Program Chair: Julia Lawall (DIKU) Program Committee: Torben Amtoft (Kansas State University) Matthias Blume (Toyota Technological Institute at Chicago) Robby Findler (University of Chicago) Alain Frisch (INRIA Rocquencourt) Patricia Johann (Rutgers University) Yukiyoshi Kameyama (University of Tsukuba) Andres Loh (Universitat Bonn) Simon Marlow (Microsoft Research Ltd.) Greg Morrisett (Harvard University) Riccardo Pucella (Northeastern University) Doaitse Swierstra (Utrecht University) Mitch Wand (Northeastern University) Joe Wells (Heriot-Watt University) Hongwei Xi (Boston University) Steve Zdancewic (University of Pennsylvania)

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Haskell Weekly News: February 20, 2006
by dons＠cse.unsw.edu.au 20 Feb '06

20 Feb '06

Haskell Weekly News: February 20, 2006 Greetings, and thanks for reading issue 25 of HWN, a weekly newsletter covering developments in the Haskell community. Each Monday, new editions are posted to [1]the Haskell mailing list and to [2]The Haskell Sequence. [3]RSS is also available. 1. http://www.haskell.org/mailman/listinfo/haskell 2. http://sequence.complete.org/ 3. http://sequence.complete.org/node/feed Announcements * The Haskell Workshop. Andres Loeh [4]released the initial call for papers for the ACM SIGPLAN 2006 [5]Haskell Workshop, to be held at Portland, Oregon on the 17 September, 2006. The purpose of the [6]Haskell Workshop is to discuss experience with Haskell, and possible future developments for the language. The scope of the workshop includes all aspects of the design, semantics, theory, application, implementation, and teaching of Haskell. 4. http://article.gmane.org/gmane.comp.lang.haskell.general/13273 5. http://www.haskell.org/haskell-workshop/2006/ 6. http://haskell.org/haskell-workshop/ * Probability Distributions. Matthias Fischmann [7]released a module for sampling arbitrary probability distribution, so far including normal (gaussian) and uniform distributions. 7. http://article.gmane.org/gmane.comp.lang.haskell.cafe/11511 * Constructor Classes. Sean Seefried [8]announced an [9]implementation of a tool to help explore constructor classes (type classes which can take constructors as arguments) described in Mark Jones' paper, [10]A system of constructor classes: overloading and implicit higher-order polymorphism. The implementation not only infers the type but also prints out a trace of the derivation tree for the syntax directed rules. 8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/11543 9. http://www.cse.unsw.edu.au/~sseefried/code.html 10. http://www.cse.ogi.edu/~mpj/pubs/fpca93.html Haskell' This section covers activity on [11]Haskell' this week. 11. http://hackage.haskell.org/trac/haskell-prime * Status Report. Isaac Jones [12]released a Haskell' status report. There is a list of proposals and a "strawman" categorization of them on [13]the wiki. The [14]timeline is also on the wiki. You'll notice that it's very aggressive; we plan to announce something at the next Haskell Workshop in September. So, check out the wiki and get on the haskell-prime mailing list! 12. http://article.gmane.org/gmane.comp.lang.haskell.cafe/11506 13. http://hackage.haskell.org/trac/haskell-prime 14. http://hackage.haskell.org/trac/haskell-prime/wiki/TimeLine * [15]More on strictness * [16]FFI Pragmas * [17]Pattern synonyms * [18]The MPTC Dilemma * [19]Labels and the MPTC Dilemma * [20]The way forward * [21]Export lists * [22]First class labels * [23]Standardising the compiler interface * [24]An existential quantifier 15. http://thread.gmane.org/gmane.comp.lang.haskell.prime/595 16. http://thread.gmane.org/gmane.comp.lang.haskell.prime/589 17. http://thread.gmane.org/gmane.comp.lang.haskell.prime/577 18. http://thread.gmane.org/gmane.comp.lang.haskell.prime/533 19. http://thread.gmane.org/gmane.comp.lang.haskell.prime/569 20. http://thread.gmane.org/gmane.comp.lang.haskell.prime/567 21. http://thread.gmane.org/gmane.comp.lang.haskell.prime/563 22. http://thread.gmane.org/gmane.comp.lang.haskell.prime/560 23. http://thread.gmane.org/gmane.comp.lang.haskell.prime/542 24. http://thread.gmane.org/gmane.comp.lang.haskell.prime/557 Discussion * Commerical Use of Haskell. Seth Kurtzberg mentioned on the #haskell irc channel that he was in the process of deploying a commercial application written in Haskell onto a production line in Taiwan. The particular application stress tests hardware performance and stability. Seth writes: "Once the compiler finally does what I think I'm telling it, the programs almost always work the first time, which is really amazing. With any substantial effort in C or C++, you are going to have hidden problems traceable to type errors. Recently, the thing that I was most pleased with was how quickly I was able to refactor the hardware stress testing code into network performance testing code." * RFC: Class-based collections. Jean-Philippe Bernardy [25]released an rfc for his initial work on a [26]class-based collections framework. The main goal is to have something usable right now, making use of generally available haskell extensions for maximum usability/portability ratio (or rather product). 25. http://article.gmane.org/gmane.comp.lang.haskell.libraries/4291 26. http://hackage.haskell.org/trac/ghc/wiki/CollectionClassFramework Darcs Corner * darcs 1.0.6. Tommy Pettersson [27]announced that the initial release candidate for Darcs 1.0.6 is available. It contains important bug fixes, some noticeable changes, and, of course, new features. 27. http://article.gmane.org/gmane.comp.version-control.darcs.user/9494 Contributing to HWN You can help us create new editions of this newsletter. Please see the [28]contributing information, send stories to dons -at- cse.unsw.edu.au. The darcs repository is available at darcs get http://www.cse.unsw.edu.au/~dons/code/hwn 28. http://haskell.org/haskellwiki/Haskell_Weekly_News

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Fast unboxed references for the IO and ST monads
by Bulat Ziganshin 19 Feb '06

19 Feb '06

Hello oleg, Wednesday, February 08, 2006, 8:37:55 AM, you wrote: >> I suggest you follow the same scheme as the unboxed array types, and >> have IOURef/STURef types, parameterised over the element type. Of >> course, we should have instances for all of the primitive numeric types >> plus Ptr, ForeignPtr, StablePtr, Bool. opc> Perhaps it may be worth to introduce a class Unpackable as described opc> at the end of opc> http://www.haskell.org/pipermail/haskell-cafe/2004-July/006400.html opc> so we may define STUArray as an instance of MArray, and other similar opc> unpackable things easier? i just implemented this neat idea. this allowed to define all sorts of unboxed arrays and references in just 300 lines of code! for those who are not seen the discussion, it's a brief presentation of implemented facilities: 1. Types IOURef/STURef represent fast alternative to the IORef/STRef types. These "unboxed references" may be used only for simple datatypes, including Bool, Char, Int..Int64, Word..Word64, Float, Double, Ptr, FunPtr, StablePtr, but for these types they are guarantee maximum speed! The unboxed references completely replaces the "Fast Mutable Ints/Words/Bools" modules used before. To use unboxed references instead of boxed ones, you just need to replace IORef/STRef in type declarations to the IOURef/STURef and add the same "U" letter to the names of operations that use these references: main = do (i :: IORef Int) <- newIORef 1 readIORef i >>= print writeIORef i 2 will become: main = do (i :: IOURef Int) <- newIOURef 1 readIOURef i >>= print writeIOURef i 2 The library includes compatibility code that allows to use IOURef/STURef on other Haskell compilers. That allows to debug code that use the unboxed references with Hugs/NHC, and use for the final optimized compilation GHC/JHC. 2. Classes MRef and Var can be used to write monad-independent code that use mutable variables. Class MRef represents monad-independent boxed references, while class Var represents the unboxed ones. You can find examples of their usage in the Streams library. These classes uses functional dependencies, so they are available only in GHC/Hugs. 3. Module GHC.Unboxed also contains implementation of UnboxedArray, UnboxedSTArray and UnboxedIOArray type constructors, what is a full analogues of UArray, STUArray and IOUArray, only much easier to implement. These definitions follow the scheme proposed by Oleg: "instance (Unboxed e) => IArray UnboxedArray e" and so on. 4. You can define new unboxed types. For example, the code that defines "instance Unboxed Bool" can be reused without any modifications for any user-defined enumeration. -- Best regards, Bulat mailto:bulatz@HotPOP.com

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GLUT gears speed
by Wolfgang Jeltsch 18 Feb '06

18 Feb '06

Hello, what's the reason behind the HOpenGL gears only being about 2/3 as fast as glxgears on my computer? Since I don't use any 3D acceleration, I thought that most of the CPU's time is spend for rendering and displaying so that speed differences between Haskell and C shouldn't matter that much. Best wishes, Wolfgang

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lazy file reader
by Atila Romero 16 Feb '06

16 Feb '06

Hi, Im starting in haskell, and wish to develop a program to process hd images, searching for file specific patterns. I will have to deal with situations where I only want to read the end of the image. My problem is: if I use hGetContents to that, the beginning of the file will allways be readen, even if only the end is important. Is there any way to tell the compiller to be 'more lazy' so if appears content!!100000 it skips a lot of data? Im not concearned with concurrency here. Átila

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CFP: Workshop on Generic Programming 2006
by Ralf Hinze 16 Feb '06

16 Feb '06

============================================================================ CALL FOR PAPERS Workshop on Generic Programming 2006 Portland, Oregon, 16th September 2006 The Workshop on Generic Programming is sponsored by ACM SIGPLAN and forms part of ICFP 2006. Previous Workshops on Generic Programming have been held in Marstrand (affiliated with MPC), Ponte de Lima (affiliated with MPC), Nottingham (informal workshop), Dagstuhl (IFIP WG2.1 Working Conference), Oxford (informal workshop), and Utrecht (informal workshop). http://www.informatik.uni-bonn.de/~ralf/wgp2006.{html,pdf,ps,txt} ============================================================================ Scope ----- Generic programming is about making programs more adaptable by making them more general. Generic programs often embody non-traditional kinds of polymorphism; ordinary programs are obtained from them by suitably instantiating their parameters. In contrast with normal programs, the parameters of a generic program are often quite rich in structure; for example they may be other programs, types or type constructors, class hierarchies, or even programming paradigms. Generic programming techniques have always been of interest, both to practitioners and to theoreticians, but only recently have generic programming techniques become a specific focus of research in the functional and object-oriented programming language communities. This workshop will bring together leading researchers in generic programming from around the world, and feature papers capturing the state of the art in this important emerging area. We welcome contributions on all aspects, theoretical as well as practical, of o adaptive object-oriented programming, o aspect-oriented programming, o component-based programming, o generic programming, o meta-programming, o polytypic programming, o and so on. Submission details ------------------ Deadline for submission: 3rd June 2006 Notification of acceptance: 24th June 2006 Final submission due: 8th July 2006 Workshop: 16th September 2006 Authors should submit papers, in postscript or PDF format, formatted for A4 paper, to Ralf Hinze (ralf(a)informatik.uni-bonn.de) by 3rd June 2006. The length should be restricted to 12 pages in standard (two-column, 9pt) ACM. Accepted papers are published by the ACM and will additionally appear in the ACM digital library. Programme committee ------------------- Roland Backhouse University of Nottingham Pascal Costanza Vrije Universiteit Brussel Peter Dybjer Chalmers University of Technology Jeremy Gibbons University of Oxford Johan Jeuring Universiteit Utrecht Ralf Hinze (chair) Universität Bonn Karl Lieberherr Northeastern University David Musser Rensselaer Polytechnic Institute Rinus Plasmeijer Universiteit Nijmegen Sibylle Schupp Chalmers University of Technology Jeremy Siek Rice University Don Syme Microsoft Research ============================================================================

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MGS 2006
by Graham Hutton 16 Feb '06

16 Feb '06

[ This graduate school is likely to be of interest to the Haskell community, and in particular includes a course on Advanced Functional Programming - Graham Hutton ] ************************************************************* Midlands Graduate School 2006 in the Foundations of Computing ************************************************************* http://www.cs.le.ac.uk/~mgs2006 The Midlands Graduate School is taking place 8 - 12 April 2006 at the University of Leicester, UK. The School provides an intensive course of lectures on the Foundations of Computing. It is very well established, having run annually for the past six years, and has always proved a popular and successful event. This year we have Luke Ong, Oxford University and Thomas Streicher, Darmstadt University as guest lecturers. The lectures are aimed at graduate students, typically in their first or second year of study for a PhD. However, the school is open to anyone who is interested in learning more about mathematical computing foundations, and we especially invite participants from UK universities and from sites participating in the APPSEM working group. Foundational courses: R Crole Leicester Operational Semantics P Levy Birmingham Typed Lambda Calculus D Pattinson Leicester Category Theory Advanced courses: T Altenkirch Nottingham Quantum Programming M Escardo Birmingham Operational Domain Theory & Topology H Nilsson Nottingham Advanced Functional Programming L Ong Oxford Game Semantics T Streicher Darmstadt Constructive Logic E Tuosto Leicester Concurrency We expect to have some grants for UK students, while APPSEM funds can be used to support students from APPSEM affiliated sites. For further details and registration please visit http://www.cs.le.ac.uk/~mgs2006 Please register soon! Places and accommodation will be allocated on a first-come, first-serve basis. Roy Crole Alexander Kurz Dirk Pattinson +---------------------------------------------------------------------+ | Dr Graham Hutton Email : gmh(a)cs.nott.ac.uk | | School of Computer Science and IT Web : www.cs.nott.ac.uk/~gmh | | University of Nottingham | | Jubilee Campus, Wollaton Road | | Nottingham NG8 1BB Phone : +44 (0)115 951 4220 | | United Kingdom Fax : +44 (0)115 951 4254 | +---------------------------------------------------------------------+ This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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PPDP'06 -- Call for Papers
by Michael Maher 16 Feb '06

16 Feb '06

[Apologies for multiple copies] Preliminary Call for Papers: PPDP 2006 Eighth ACM-SIGPLAN International Symposium on Principles and Practice of Declarative Programming Venice, Italy, 10-12 July, 2006 IMPORTANT DATES Submission 15 March 2006 Notification 22 April 2006 WEB SITES: PPDP 2006: http://www.dsi.unive.it/ppdp2006/ PPDP: http://pauillac.inria.fr/~fages/PPDP/ SCOPE OF THE CONFERENCE: PPDP 2006 aims to provide a forum that brings together those in 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, AI languages and knowledge representation languages used, for example, in the "semantic web". The goal is to stimulate research in the use of logical formalisms and methods for specifying, performing, and analyzing computations, and to stimulate cross-fertilization by including work from one community that could be of particular interest and relevance to the others. Topics of more specific interest are enhancements to such formalisms with mechanisms for mobility, modularity, concurrency, object-orientation, security, and static analysis. At the level of methodology, the use of logic-based principles in the design of tools for program development, analysis, and verification relative to all declarative paradigms is of interest. Papers related to the use of declarative paradigms and tools in industry and education are especially solicited. This list is not exhaustive: submissions related to new and interesting ideas relating broadly to declarative programming are encouraged. Prospective authors are encouraged to communicate with the Program Chair about the suitability of a specific topic. TOPICS (Not exhaustive): Logic, Constraint, and Functional Programming; Database, AI, and Knowledge Representation Languages; Visual Programming; Executable Specification Languages; Applications of Declarative Programming; Methodologies for Program Design and Development; Declarative Aspects of Object-Oriented Programming; Concurrent Extensions to Declarative Languages; Declarative Mobile Computing; Integration of Paradigms; Proof Theoretic and Semantic Foundations; Type and Module Systems; Program Analysis and Verification; Program Transformation; Abstract Machines and Compilation; Programming Environments EVALUATION OF SUBMISSIONS: Submitted papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. They should include a clear identification of what has been accomplished and why it is significant. They must describe original, previously unpublished work that has not been simultaneously submitted for publication elsewhere. Authors who wish to provide additional material to the reviewers beyond the 12-page limit can do so in clearly marked appendices: reviewers are not required to read such appendices. Submissions that do not meet these guidelines may not be considered. PROCEEDINGS: Proceedings will be published by ACM Press. ACM formatting guidelines are available online, along with formatting templates or style files for LaTeX, Word Perfect, and Word: http://www.acm.org/sigs/pubs/proceed/template.html. Authors of accepted papers will be required to sign the ACM copyright form. RELATED EVENTS: PPDP 2006 will be co-located with the 33rd International Colloquium on Automata, Languages and Programming (ICALP 2006), which will take place 9-16 July 2006. See http://icalp06.dsi.unive.it for more information. CONFERENCE CHAIR: Annalisa Bossi, U. Ca' Foscari di Venezia web: http://www.dsi.unive.it/~bossi/, email: bossi(a)dsi.unive.it PROGRAM CHAIR: Michael Maher, National ICT Australia web: http://www.cse.unsw.edu.au/~mmaher, email: michael.maher(a)nicta.com.au PROGRAM COMMITTEE: Nick Benton (Microsoft Research, UK) Annalisa Bossi (U. Ca' Foscari di Venezia, Italy) Manuel Chakravarty (U. NSW, Australia) Bart Demoen (K. U. Leuven, Belgium) Moreno Falaschi (U. Udine, Italy) Radha Jagadeesan (DePaul U., USA) Bharat Jayaraman (SUNY Buffalo, USA) Yukiyoshi Kameyama (U. Tsukuba, Japan) Andy King (U. Kent, UK) Francois Laburthe (Bouyges, France) David Sands (Chalmers U., Sweden) Christian Schulte (KTH, Sweden) Pascal Van Hentenryck (Brown U., USA) Roland Yap (NUS, Singapore) PREVIOUS PPDP CONFERENCES: Paris (1999), Montreal (2000), Firenze (2001), Pittsburgh (2002), Uppsala (2003), Verona (2004), Lisboa (2005).

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Haskell Workshop 2006 Call for papers
by Andres Loeh 16 Feb '06

16 Feb '06

Apologies for multiple copies; feel free to distribute further. Cheers, Andres

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compares :: Ord a => a -> a -> Ordering -> Ordering
by Ben Rudiak-Gould 15 Feb '06

15 Feb '06

I just realized that the class Ord should have an additional method: class Eq a => Ord a where compares :: a -> a -> Ordering -> Ordering compares x y d = case compare x y of { EQ -> d ; o -> o } ... This would make writing Ord instances much easier: instance (Ord a, Ord b, Ord c, Ord d) => Ord (a,b,c,d) where compares (a1,b1,c1,d1) (a2,b2,c2,d2) = compares a1 a2 . compares b1 b2 . compares c1 c2 . compares d1 d2 -- Ben

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