- Haskell - Haskell.org

seeking lore of the QuickCheck masters
by nr＠eecs.harvard.edu 30 Apr '03

30 Apr '03

I am playing around with an implementation of a little language, and I would like to use QuickCheck to test my code. My problem is that I want to test only well-typed terms. I don't know how to craft my `arbitrary' functions so that the probability of generating a well-typed term is more than vanishingly small. Can anybody pass on interesting tips and tricks that might help? Norman

8 16

Re: Is it possible to build in a file in a haskell program??
by Alexandre Weffort Thenorio 29 Apr '03

29 Apr '03

Yeah just as I expected it. It wrote the whole program OK but when it comes to: mybinfile = It just wrote all the weird stuff that you see if you try opening a bin file in notepad. The weird part is that it didn't write the whole thing, just part of it. Is it supposed to be like that?? I did use readfile function to read the bin file, but just in case how to make a handle into a string, for example: basic = "module MyBinFile ( mybinfile ) where\nmybinfile :: String\nmybinfile = \"" do handle <- openFile "mybinfile.hs" WriteMode --File to be written to hand <- readfile "file.bin" hPutStrLn handle (basic ++ hand ++ "\"") That's what I did basically and I only used readFile to read the bin file because hPutStrLn requires a String and openFile gives me a Handle so is it possible to make a handle to a String?? Also what am I doing wrogn because apparently I am not getting stuff like /x01/x02 but weird stuf like: DÅÍo in the created file. Best Regards Alex ----- Original Message ----- From: "Keith Wansbrough" <Keith.Wansbrough(a)cl.cam.ac.uk> To: "Alexandre Weffort Thenorio" <alethenorio(a)home.se> Sent: Tuesday, April 29, 2003 8:11 PM Subject: Re: Is it possible to build in a file in a haskell program?? > > Thanks but I am not sure what exactly you mean. I've done this: > [..] > > Tried compiling main.hs file but it says "Failed to load interface for > > MyBinFile". > > This means you haven't compiled MyBinFile. > > Do you know about Haskell modules? You should read the relevant section of the Haskell Report (www.haskell.org/onlinereport/) and also the documentation of your compiler. > > --KW 8-) > -- > Keith Wansbrough <kw217(a)cl.cam.ac.uk> > http://www.cl.cam.ac.uk/users/kw217/ > University of Cambridge Computer Laboratory. > >

1 0

Re: Is it possible to build in a file in a haskell program??
by Alexandre Weffort Thenorio 29 Apr '03

29 Apr '03

Sorry. As a begginner (Kinda) with haskell I completelly forgot how to work with Modules but anyway I completelly understood what you meant now. My problem actually is writing the program thats write the little haskell program (Or a String) out of the bin file. Can you give me a clue? Of course most of the code is easy but the tricky part comes to the string representing the file, I mean won't haskell just write exactly like the bin file is written (Thus in weird stuff can't just be copied and pasted) Or maybe if I read the file in Binary mode and write it in Text mode (Using IOExts Library)??? Best Regards Alex ----- Original Message ----- From: "Keith Wansbrough" <Keith.Wansbrough(a)cl.cam.ac.uk> To: "Alexandre Weffort Thenorio" <alethenorio(a)home.se> Sent: Tuesday, April 29, 2003 8:11 PM Subject: Re: Is it possible to build in a file in a haskell program?? > > Thanks but I am not sure what exactly you mean. I've done this: > [..] > > Tried compiling main.hs file but it says "Failed to load interface for > > MyBinFile". > > This means you haven't compiled MyBinFile. > > Do you know about Haskell modules? You should read the relevant section of the Haskell Report (www.haskell.org/onlinereport/) and also the documentation of your compiler. > > --KW 8-) > -- > Keith Wansbrough <kw217(a)cl.cam.ac.uk> > http://www.cl.cam.ac.uk/users/kw217/ > University of Cambridge Computer Laboratory. > >

1 0

ESS2003: Language and Speech Technology for Language Learning
by Steven Krauwer 29 Apr '03

29 Apr '03

SECOND ANNOUNCEMENT and CALL for PARTICIPATION The 11th ELSNET Summer School on Language and Speech Communication Topic: Language and Speech Technology in Language Learning Lille (France), Monday July 7 - Friday July 18, 2003 Organized by the University of Lille 3 We are happy to announce that registration for the 11th ELSNET Summer School is now open. For this school we have chosen a topic of great relevance to researchers and developers in Europe and in other multilingual environments: the use of language and speech technology in language learning, both of spoken and of written language. The goal of this workshop is to get young researchers on a track that will eventually contribute to an important application area. The underlying vision (or dream) is The automatic animated language tutor. + Audience and aims: We see the school as mainly research and development oriented, and hence the primary audience are researchers, developers and integrators who will make our vision happen (rather than teachers who would use it). Both technological and pedagogical aspects will be taken into consideration The aims are: * to make the students familiar with the main principles and problems of language learning/teaching * to make them familiar with current best practice in computer assisted language learning * to make them familiar with the main challenges in computer assisted language learning Participants are expected to have a general computational background and some familiarity with language or speech research and/or processing. After completion of the summer school participants should be able to function in teams aimed at designing or implementing tools, environments or courses for Computer Assisted Language Learning (abbreviated CALL). + Course programme: The provisonal programme is available at http://www.elsnet.org/ess2003/schedule.html The 2-weeks programme comprises the following courses: * Introduction to CALL (Teacher: Jozef Colpaert, [Univ of Antwerp]) * Introduction to natural language processing for CALL (Teacher: Wolfgang Menzel [Univ of Hamburg]) * Introduction to speech processing for CALL (Teacher: Philippe Delcloque [MSEC Manchester]) * Using NLP tools in CALL (hands-on) (Teacher: Wolfgang Menzel [Univ of Hamburg]) * Using Speech tools in CALL (hands-on) (Teacher: Michael McTear [Univ of Ulster]) * CALL design and interfaces (Teacher: Philippe Delcloque [MSEC Manchester]) * Grammatical and morphological error diagnosis (Teacher: Lars Borin [Univ of Gothenburg]) * Systems for pronunciation training (Teacher: Anne-Marie Oster [KTH Stockholm]) * Building a grammatical CALL system (hands-on) (Teacher: Lars Borin [Univ of Gothenburg]) * Building a speech CALL system (hands-on) (Teacher: Michael McTear [Univ of Ulster]) All students attend the same full programme, except for the hands-on sessions, where students can sign up for either NLP or Speech oriented streams. In special student sessions students can present their own work. The presentations will be published on the ELSNET website. Please note that the number of places for this summer school is limited and that early registration is recommended. The working language of the Summer School will be English. + Fees: Category Registration fee (euro) Students 125 Academic staff 250 Commercial organisations 500 ELSNET members are entitled to a 20% discount + Food and accommodation: The cost of accommodation (on campus) will be 20 euro per night Meals will be free. + Registration, grants and other information: For detailed information about registration procedures and deadlines, fees, accommodation, grant possibilities, venue, course and social programme, etc visit the ESS2003 website at http://www.univ-lille3.fr/ESS2003 or send an email to the local organizers at elsnetadmin(a)univ-lille3.fr A limited number of grants (covering the cost of accommodation) may be available. Details and application forms will be published on the website. For information about the programme visit the ESS2003 website or http://www.elsnet.org/ess2003 or contact the chair of the programme committee, Steven Krauwer (steven.krauwer(a)elsnet.org) __________________________________________________________________________ Steven Krauwer, ELSNET coordinator, UiL-OTS, Trans 10, 3512 JK Utrecht, NL phone: +31 30 253 6050, fax: +31 30 253 6000, email: s.krauwer(a)elsnet.org http://www.elsnet.org

1 0

FIRST CALL for PAPERS -- FLOPS2004
by pjs＠cs.mu.oz.au 28 Apr '03

28 Apr '03

------- Blind-Carbon-Copy X-Mailer: exmh version 2.5 10/15/1999 with version: MH 6.8.4 #1[UCI] To: pjs(a)cs.mu.oz.au Subject: FIRST CALL for PAPERS -- FLOPS2004 From: pjs(a)cs.mu.oz.au Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 29 Apr 2003 09:05:08 +1000 Message-ID: <16046.1051571108(a)muldi.cs.mu.oz.au> Sender: pjs(a)muldi.cs.mu.oz.au Apologies if you recieve this mail more than once. - -------------------------------------------------- *********************************************************************** * * * CALL FOR PAPERS * * * * Seventh International Symposium on Functional and Logic Programming * * (FLOPS 2004) * * * * Nara-Ken New Public Hall, Nara, Japan * * April 7-9, 2004 * * * * (http://logic.is.tsukuba.ac.jp/FLOPS2004/) * * * *********************************************************************** Background ========== The symposium is a forum for research on all issues concerning functional programming and logic programming. In particular, it wants to stimulate the cross-fertilization as well as integration of the two paradigms. The symposium takes place about every 1.5 years in Japan. Previous FLOPS meetings were held in Fuji Susono (1995), Shonan Village (1996), Kyoto(1998), Tsukuba (1999), Tokyo (2001) and Aizu (2002). Topics ====== The Seventh International Symposium on Functional and Logic Programming (FLOPS 2004) 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, industrial applications, graphical user interfaces, internet applications, database connection, formal methods and model checking Invited Speakers ================ The following three distinguished researchers have accepted to give invited talks at FLOPS 2004. * Masami Hagiya University of Tokyo * Carsten Schuermann Yale University * Peter Selinger University of Ottawa Submissions =========== 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. All submissions must be written in English and can be up to 15 proceedings pages long. Authors are strongly encouraged 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). Submission is Web-based. In order to submit a paper, authors should fill in the submission form available at http://logic.is.tsukuba.ac.jp/FLOPS2004/submission.html where more detailed instructions are given. If submission through the Web is not possible, five hard copies may be sent to Yukiyoshi Kameyama Institute of Information Sciences and Electronics University of Tsukuba Tennodai 1-1-1, Tsukuba, 305-8573, JAPAN Publication and presentation of accepted contributions ====================================================== The Proceedings of FLOPS 2004 will be published by Springer Verlag in the Lecture Notes in Computer Science (LNCS) series. LNCS is published, in parallel to the printed books, in full-text electronic version and final versions of the papers will need to be provided electronically including the source files. Proceedings will be available at the conference. One author of each accepted contribution is expected to attend the Symposium in order to present it. Important Dates =============== Submission Deadline: October 1, 2003 Notification: December 15, 2003 Final Version: January 15, 2004 Symposium: April 7-9, 2004 Program Co-Chairs ================= Yukiyoshi Kameyama University of Tsukuba, Japan Peter J. Stuckey University of Melbourne, Australia E-Mail: flops(a)logic.is.tsukuba.ac.jp Program Committee ================= Francois Fages INRIA Rocquencourt Herman Geuvers Nijmegen University Michael Hanus University of Kiel Martin Hofmann University of Muenchen Haruo Hosoya Kyoto University Yukiyoshi Kameyama University of Tsukuba Naoki Kobayashi Tokyo Institute of Technology John Lloyd Australian National University Aart Middeldorp University of Tsukuba Atsushi Ohori JAIST German Puebla Technical University of Madrid Morten Rhiger IT-University of Copenhagen Amr Sabry Indiana University Peter J. Stuckey University of Melbourne Martin Sulzmann National University of Singapore Kazunori Ueda Waseda University Philip Wadler Avaya Labs Local Arrangements Chair ======================== Jacques Garrigue Kyoto University Sponsors ======== FLOPS2004 is supported by Japan Society of Software Science and Technology (JSSST), Association for Logic Programming (ALP), and Asian Association for Foundation of Software (AAFS) [planed]. ------- End of Blind-Carbon-Copy

1 0

Online judge and Haskell?
by Steffen Mazanek 28 Apr '03

28 Apr '03

Hello, it's me again and I have a new mad idea. There are a lot of programming contests out there and unfortunately most (all?) of them do not allow Haskell code till now! I think, this is hard to accept. Why not ask the people which run acm.uva.es/problemset to provide their problem sets, input and output files and the basic judging software and install it at haskell.org? Alternatively this may be a nice project for a student. I think an adaption of this software to permit Haskell code can not be that difficult! Do you think there is a need for such a project? Maybe it could help Haskell to become a part of official programming contests and hence to gain more popularity. I'm sorry to say, that due to another project my free time is very limited so I can not get it going by only myself. Ciao, Steffen -- Haskell: that's where I just curry until fail, unwords any error, drop all undefined, maybe break, otherwise in sequence span isControl and take max $, id: (d:[])

2 1

REMINDER - Contributions to HC&A Report (May 2003 edition)
by C.Reinke 28 Apr '03

28 Apr '03

Dear Haskeller, as you can see from the Report's topics page at http://www.haskell.org/communities/topics.html , both confirmations from well-known contributors and offers from new contributors are still a bit sparse at this stage (not to mention actual contributions:), although we're making progress. First, many thanks to those who simply write their reports and are done with it! But, if the call for contributions should have caught you in your extended Easter holidays, could you please let me know as soon as possible how long that will delay your contributions?-) I wouldn't want to extend the general target deadline by much, as people should really get going on their Haskell Workshop papers soon (hint!-), but we may be able to accomodate individual delays. Just keep in mind that this is really an informal exercise: it probably takes less time to sit down and write an update of your report than it takes to worry about delays and making time.. Otherwise, could everybody send in their individual reports ** by the end of THIS week ** ? Please?-) Thanks, Claus -- Haskell Communities and Activities Report (May 2003 edition) Contributions are due in by the end of THIS week! http://www.haskell.org/communities/ ======================= original call for contributions follows Dear Haskellers, following the early reminder in the preface of the last edition, you've probably been waiting already, contribution in hand, eager to send it in for the May edition of our report (hey, editors can have their dreams, too!-), so here it is: *your* invitation to contribute to the fourth edition of the Haskell Communities & Activities Report http://www.haskell.org/communities/ These bi-annual HC&A Reports should give a birds-eye view of Haskell development over the last 6 months, and perhaps an outlook over concrete plans for the next 6 months. The current plan is to get contributions in by the end of April, and to get the collective report out early next month (some of you will find this an excellent opportunity to collect your thoughts about what to submit to this year's Haskell Workshop, btw;-). The general idea is to update all existing summaries (these reports are really about recent/current activities), to drop any topics that haven't had any activity for two consecutive 6-month periods, and to add any new developments or topics for which no-one contributed summaries to the previous edition, while trying to keep the whole from blowing up (last time, we ended up with about 30 pages). New suggestions for current hot topics, activities, projects, .. are welcome - especially with names and addresses of potential contacts, but here is a non-exclusive list of likely topics: General Haskell developments; Haskell implementations; Haskell extensions; Standardization and documentation; Haskell tutorials, how-tos and wikis; Organisation of Haskell tool and library development; Haskell-related projects and publications; Feedback from specialist mailing lists to the Haskell community as a whole; Haskell libraries or tools; Applications of Haskell; Haskell announcements; .. all (recent) things Haskell Announcements: if you've announced anything new on the Haskell list over the last six months, you'll want to make sure that is reflected in this edition. Project pings: if you're maintaining a Haskell tool/library/.., you'll want to let everyone know that it is still alive and actively maintained, even if there may have been no new additions. Tutorials: if you've fought with some previously undocumented corner of Haskell, and have been kind enough to write down how you did manage to build that networking program, or if you've written a tutorial about some useful programming techniques/patterns, this is your opportunity to spread the word (btw, short, topic-specific, and hands-on tutorials that only show how to achieve a certain practical task would do a lot to make things easier for new Haskellers - Erlang and Perl folks seem to be good at this kind of thing, but why not have a similar effort for Haskell?) Applications: if you've been working quietly, using Haskell for some interesting project or application (commercial or otherwise), you might want to let others know about it, and about your experiences using the existing tools and libraries; are you using Haskell on your job? Feedback: if you're on one of the many specialist Haskell mailing lists, you'll want to report on whatever progress has been made there (GUI API discussions, library organisation, etc.) If you're unsure whether a contact for your area of work has come forward yet, have a look at the report's potential topics page, or get in touch with me. I've contacted last time's contributors, hoping they will volunteer to provide updates of their reports, and will update the contacts on the topics page fairly regularly. But where you don't yet see contacts listed for your own subject of interest, you are very welcome to volunteer, or to remind your local community/project team/mailing list/research group/etc. that they really ought to get their act together and let the Haskell community as a whole know about what they've been doing!-) A typical summary report about a tool/library/project/application/.. would be between 1 and 3 paragraphs of ASCII text (what's it about? major topics and results since the last report? current hot topics? major goals for the next six months?) plus pointers to material for further reading (typically to a home page, or to mailing list archives, specifications and drafts, implementations, meetings, minutes,..). Browsing through previous editions should give you a good idea. Looking forward to your contributions, Claus -- Haskell Communities and Activities Report (May 2003 edition) All contributions are due in by the end of April 2003! http://www.haskell.org/communities/ _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

1 0

Re: Polymorphic stanamically balanced binary trees
by Okasaki, C. DR EECS 28 Apr '03

28 Apr '03

oleg describes an implementation of AVL trees that have two main features: 1. The trees are heterogenous (elements within the same tree can have different types). 2. The balance condition is partially enforced by the type checker, and partially by run-time checks. For feature 1, you can take your favorite solution for heterogenous lists (existentials, type dynamic, ...) and extend it to trees. This problem is orthogonal to the balance problem, and I'll ignore it in the rest of this post. For feature 2, there are lots of interesting approaches to push this kind of check into the type checker. For example, Hongwei Xi has several variations that do this using dependent types. It can also be done entirely with nested types. I think I first saw this done for AVL trees by Ross Paterson in 1998. First, here's a type that for trees of height h, given types for trees of height h-1 (t1) and for trees of height h-2 (t2). data Node a t1 t2 = Left t1 a t2 | Even t1 a t1 | Right t2 a t1 Next, here's a type for trees of arbitrary height, given types for trees of height h-1 and h-2. data Tree a t1 t2 = Zero t2 | Succ (Tree a (Node a t1 t2) t1) To start things off, we set t2 to the type of trees of height 0 and t1 to the type of trees of height 1. type AVLTree a = Tree a a () For example, a tree like 1 / 2 would be encoded as Succ | Succ | Zero | Left(1) / \ Even(2) () / \ () () Using polymorphic recursion, you can then implement typical tree functions like insert and delete. The type checker will catch any attempt to build an unbalanced tree. Note that there are no run-time checks in this approach. That last statement is a little bit of a lie. There is no run-time typechecking going on, but there are run-time artifacts of this algorithm, namely the Zero and Succ nodes which encode the height of the tree. Zero and Succ are data constructors, not type constructors as they are in oleg's version, so you have to walk through them at run-time. -- Chris

1 0

No more numeric-quest?
by Mike Fagan 27 Apr '03

27 Apr '03

Dear Haskell Guys, None of the www.numeric-quest.com pages are available. Has anyone mirrored that stuff elsewhere? Thanks, Mike Fagan

2 1

RE: Super Haddock (was Re: Literate Programming)
by Simon Marlow 27 Apr '03

27 Apr '03

> This seems like a good way of transitioning from .lhs to > haddock'd .hs. In > the long run, I think we (meaning Simon :-) should to extend > haddock to > take the place of the .lhs style of documenting code. To generate .hs from .lhs, the right way is to use GHC: $ ghc -E Foo.lhs -o Foo.hs The great thing about this is that it goes through the same preprocessing stages that your source goes through in order to compile it. So for example if you use CPP on your source too, just say 'ghc -E -cpp' to get the preprocessed output. > I use haddock to document interfaces for modules and it works > wonderfully > for that (and it would be even better if I could use haddock comments > inside records and in between constructor arguments, hint, hint). > > But I find myself using it in comments within code > (especially within local > functions) too. Perhaps a haddock that had two modes (one > for interfaces, > one for implementation) would work. The interface mode would > work as it > does now. The implementation mode would produce a .html > version of the > entire module, using haddock comments to mark it up. > > Simon: how much work would this be? That's an interesting idea. It's not at all what Haddock was intended for, but that's not to say it couldn't be done! There are some issues to do with how you want the output to look: should it retain the indentation of the original source, or ident according to some fixed style? If you want the indentation from the original source then Haddock's front end will need some changes to support retaining that information. Throwing away the original indentation and generating output indented according to a fixed style would be rather easier. Cheers, Simon

10 10