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APLAS'06: Early registration deadline: 20 October!!
by Manuel M T Chakravarty 13 Oct '06

13 Oct '06

*** Early Registration Deadline: 20 October *** Call for Participation 4th Asian Symposium on Programming Languages and Systems November 8-10, 2006 Sydney, Australia http://www.cse.unsw.edu.au/~aplas06/ http://www.kb.ecei.tohoku.ac.jp/aplas2006/ Scope of the Conference ----------------------- 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. Conference Registration ----------------------- Registration information for APLAS 2006 is available at http://www.cse.unsw.edu.au/~aplas06/registration.html

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GADT: call for proper terminology
by oleg＠pobox.com 13 Oct '06

13 Oct '06

Niklas Broberg wrote: > Annotate the data type using a GADT: > data MyData a where > MyCon :: MyData a The range of the data constructor MyCon is the entire type MyData a -- so the above data type is the regular algebraic data type, and can be written just as data MyData a = MyCon which, some say, makes the fact 'a' is phantom, and the overall intent clearer. One may hear phrases how generally awesome and indispensable GADT are; it is distressing to realize then that sometimes (often?) one is talking about regular algebraic data types, only in the `where' syntax. It helps to reduce confusion about the merits of various features and additions to Haskell if we use the term GADT exclusively for truly _generalized_ algebraic data types.

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building shared objects
by Jeremy Wazny 13 Oct '06

13 Oct '06

Hi all, I'm wondering if anybody has had any success building shared objects from Haskell code on x86 Linux and/or Sparc Solaris. I have some Haskell source which I am trying to integrate into a C/C++ library which I am maintaining at the same time. The performance of the Haskell code is not an issue. The key limitation is that I need to be able to package the whole thing as a single .so object file. Put simply, I have a Haskell module which exports one of its functions via the FFI, using the ccall calling convention. I need to compile that module, and then link the resulting object, along with some other objects, into a single shared object. It seems there is no straightforward way to achieve this with any Haskell implementation on anything other than windows (by building a DLL.) A few possibilties have occurred to me, and I'd be interested to know if anybody has tried any of these with any success. 1. Use GHC with unregisterised libraries that have been compiled by gcc using -fPIC. I haven't been able to figure out how to actually build unregisterised libraries. I tried compiling the GHC 6.4.2 sources (using GHC 6.4.2) with `GhcUnregisterised = YES' in mk/build.mk, only to have the assembler fail. Has anyone else tried this recently? I sent a message to the GHC-users mailing list with more details, but haven't had a response yet. 2. Use nhc98 with libraries and run-time compiled with gcc and -fPIC. I have no idea whether this is feasible. 3. Link in a version of yhc's yhi interpreter, compiled with -fPIC. The shared object would have to produce some temporary files containing all of the pre-compiled byte code for the interpreter to read and execute. (We're already assuming that the platform the system runs on is completely trustworthy.) 4. Alternative 3 might also be possible using Hugs. I'm not sure that I can rely on any of these approaches - provided I can even get any of them working. Does anybody know of a good solution to this problem? The alternative is to admit defeat and rewrite all the Haskell code as C++, which is pretty depressing. Regards, Jeremy ____________________________________________________ Do you Yahoo!? Listen to your personal radio station on Yahoo!7 Music http://au.music.yahoo.com/launchcast/setup.asp

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Getting a function dependency graph from source
by Durward McDonell 12 Oct '06

12 Oct '06

Hello. This seems like a basic question, but I haven't been able to find an answer. I have a pile of Haskell code that is compiled into a library, and a Haskell program that uses this library. What I would like is something that will look at my program and follow the function calls until it gets to the Prelude. I want to know which functions in the library and in the Prelude actually get used (at least potentially). I believe Hat only looks at traces of an actual run of the program, and so doesn't quite give me what I want. I also think I could do this with the haskell-src library, but it looks like a lot of work to understand that and use it. Thanks. -- Durward McDonell durward.mcdonell(a)jhuapl.edu

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ICFP 2007 call for workshop proposals
by Graham Hutton 12 Oct '06

12 Oct '06

---------------------------------------------------------------------- CALL FOR WORKSHOP PROPOSALS ICFP 2007, the 12th ACM SIGPLAN International Conference on Functional Programming 1-3 October 2007, Freiburg, Germany The 12th ACM SIGPLAN International Conference on Functional Programming (ICFP 2007) will be held in Freiburg, Germany from 1st to 3rd October 2007. ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. Proposals are invited for workshops to be affiliated with ICFP 2007 and sponsored by SIGPLAN. These workshops should be more informal and focused than ICFP itself, include sessions that enable interaction among the workshop attendees, and be fairly low cost. The preference is for one-day workshops, but other schedules can also be considered. The workshops themselves will be held on 30th September, 4th October, and 5th October 2007. SUBMISSION DETAILS Deadline for submission: 17th November 2006 Notification of acceptance: 15th December 2006 Prospective workshop organisers are invited to submit a completed workshop proposal form in plain text format to the ICFP 2007 workshop co-chairs (Graham Hutton and Matthias Blume), via email to icfp07-workshops at cs.nott.ac.uk by 17th November 2006. Please note that this is a firm deadline. Organisers will be notified if their proposal is accepted by 15th December 2006, and if successful are required to produce a final report after the workshop has taken place that is suitable for publication in SIGPLAN Notices. SELECTION COMMITTEE The workshop proposals will be evaluated by a committee comprising the following members of the ICFP 2007 organising committee, together with the members of the SIGPLAN executive committee. Graham Hutton University of Nottingham Workshops co-chair Matthias Blume TTI at Chicago Workshops co-chair Ralf Hinze Universitat Bonn General chair Norman Ramsey Harvard University Program chair FURTHER INFORMATION Any queries regarding ICFP 2007 workshop proposals should be addressed to the workshops co-chairs (Graham Hutton and Matthias Blume), via email to icfp07-workshops at cs.nott.ac.uk. USEFUL LINKS Call for workshop proposals http://www.cs.nott.ac.uk/~gmh/icfp07-workshops.html Workshop proposal form http://www.cs.nott.ac.uk/~gmh/icfp07-workshops-form.txt ICFP 2007 home page http://www.informatik.uni-bonn.de/~ralf/icfp07.html ---------------------------------------------------------------------- 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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ANNOUNCE: Generic Haskell 1.60 (Diamond)
by Alexey Rodriguez Yakushev 11 Oct '06

11 Oct '06

Generic Haskell version 1.60 (Diamond) ==================================== We are happy to announce the fourth release of Generic Haskell, an extension of Haskell that facilitates generic programming. Generic Haskell includes the following features: * type-indexed values -- generic functions that can be instantiated on all Haskell data types. * type-indexed types -- types which are indexed over the type constructors underlying Haskell datatypes. The Generic Haskell compiler takes Generic Haskell source and produces Haskell code. Changes since 1.42 (Coral) -------------------------- * Generic Views as described in the Generic Views paper [1] are now sup- ported. * This release also corrects a few errors that occur with default cases, and some of the library functions have been improved. Download -------- The Generic Haskell compiler is available in source and binary distributions. Binaries for Linux and MacOSX are available. These are available from: http://www.generic-haskell.org/compiler.html The documentation is also available separately from that page. For more general information, point your browser to: http://www.generic-haskell.org Why Generic Haskell? -------------------- Software development often consists of designing datatypes, around which functionality is added. Some functionality is datatype specific, whereas other functionality is defined on almost all datatypes in such a way that it depends only on the structure of the datatype. A function that works on many datatypes in this way is called a generic function. Examples of generic functionality include editing, pretty-printing or storing a value in a database, and comparing two values for equality. Since datatypes often change and new datatypes are introduced, we have developed Generic Haskell, an extension of the functional programming language Haskell that supports generic definitions, to save the programmer from (re)writing instances of generic functions. The original design of Generic Haskell is based on work by Ralf Hinze. Pleasant programming, The Generic Haskell Team at Utrecht University info(a)generic-haskell.org [1] Stefan Holdermans, Johan Jeuring, Andres Löh, and Alexey Rodriguez. Generic views on data types. In Tarmo Uustalu, editor, Proceedings 8th International Conference on Mathematics of Program Construction, MPC 2006, LNCS 4014, pages 209 - 234, 2006, © Springer-Verlag.

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Fun in the Afternoon: Thurs 16th Nov in Oxford
by Jeremy.Gibbons＠comlab.ox.ac.uk 11 Oct '06

11 Oct '06

Dear colleagues, Graham Hutton and Conor McBride at Nottingham and I are organizing a termly seminar "Fun in the Afternoon" on functional programming and related topics. The idea is to have a small number of talks as an antidote to mid-term blues, three afternoons a year. The hope is that talks will be informal and fun, and that there will be plenty of scope for discussion and chat as well. Fun in the Afternoon will be peripatetic. The first meeting will be in Oxford University Computing Laboratory on Thursday 16th November, and Phil Wadler of the University of Edinburgh will be opening proceedings. All are welcome, but if you'd like to come, could you please drop me (Jeremy Gibbons) a line so that I have an idea of numbers? If you'd like to give a talk, please also propose a title and a duration. We haven't yet fixed the timetable, because it depends in part on what offers of talks we get. But our current plan is to have talks 14:00-14:45 and 15:30-17:00. Brings sandwiches to eat together beforehand, and join us for drinks in a pub afterwards. There's a webpage with more information at http://sneezy.cs.nott.ac.uk/fun/ This page also explains how to subscribe to the mailing list, to which all further announcements will be sent. Directions to OUCL are at http://web.comlab.ox.ac.uk/oucl/about/directions.html Jeremy, Graham and Conor

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ANNOUNCE: Cabal version 1.1.6
by Duncan Coutts 11 Oct '06

11 Oct '06

The Haskell Cabal The Common Architecture for Building Applications and Libraries. http://haskell.org/cabal/ Cabal version 1.1.6 is now available. It is included in GHC version 6.6. For other Haskell implementations or older versions of GHC you can install it separately: DOWNLOAD: http://www.haskell.org/cabal/download.html http://www.haskell.org/cabal/release/latest/cabal-1.1.6.tar.gz DOCUMENTATION: http://www.haskell.org/cabal/release/latest/doc/users-guide/ http://www.haskell.org/cabal/release/latest/doc/API/ See both the README file and the changelog for interface changes: http://www.haskell.org/cabal/release/latest/changelog BUGS: Report bugs using our bug tracker: http://hackage.haskell.org/trac/hackage/newticket or to the libraries(a)haskell.org mailing list.

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ANNOUNCE: GHC version 6.6
by Ian Lynagh 11 Oct '06

11 Oct '06

=========================================================== The (Interactive) Glasgow Haskell Compiler -- version 6.6 =========================================================== The GHC Team is pleased to announce a new release of GHC. There have been many changes since the 6.4.2 release. For details, see the release notes here: http://haskell.org/ghc/docs/6.6/html/users_guide/release-6-6.html How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: http://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language; the current language version is Haskell 98, agreed in December 1998 and revised December 2002. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://hackage.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: http://hackage.haskell.org/trac/ghc/wiki/Contributors Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: http://www.haskell.org/ghc/docs/latest/html/building/building-guide.html Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: http://hackage.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: http://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: http://www.haskell.org/ghc/reportabug

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Classes with no data type
by Thomas Davie 10 Oct '06

10 Oct '06

Hi, I've met an interesting problem in terms of how to type a data structure and the functions that operate upon it. The problem centres around a single data type. This data type can be constructed in multiple ways using different functions, depending on the options the user specifies. That's all simple enough. The problem really comes later on. Depending on the function used generate the data structure I want to use different functions later on for example, to display the data. Thus I have a typical classes problem, in that I have several implementations of essentially the same function for different circumstances. The problem is, they must all operate on the same data type, so I cannot define them as seperate instances. Anyone got any ideas how to type this? Bob

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