April 2002 - Haskell - Haskell.org

Parsec: No newline after last line and 'many'
by Till Doerges 08 Apr '02

08 Apr '02

Hi folks, when trying to write a parser for unix-style textfiles, I stumbled across the problem having to distinguish between lines w/ a newline character at the end and lines w/o a newline at the end (i.e. the last line in a file doesn't have to have it). Eventually I want to be able to use my parser 'linep' with 'many' on no matter which text-files. The first version I tried, was --- snip --- skip1 :: Parser() skip1 = do anyChar return() linep :: Parser(String) linep = do { cs <- many (noneOf "\n") ; skip1 ; return cs } --- snap --- Well, this only works, if the last line in the file is also terminated by '\n'. So, I tried to be smarter using: --- snip --- lineWith :: Parser(String) lineWith = try (do { cs <- many (noneOf "\n") ; skip1 ; return cs }) lineWithOut :: Parser(String) lineWithOut = many anyChar linep :: Parser(String) linep = lineWith <|> lineWithOut <?> "line" --- snap --- But this doesn't do the trick either, instead it'll overflow my stack if used in conjunction w/ 'many': --- snip --- parse (do {many linep}) "stdin" (unlines ["hallo","ballo"]) ^CInterrupted. ReadOrig> parse (do {many linep}) "stdin" ("hallo\nballo") ^CInterrupted. --- snap --- Avoiding many OTOH works fine: --- snip --- parse (do {linep;linep}) "stdin" (unlines ["hallo","ballo"]) Right "ballo" ReadOrig> parse (do {linep;linep}) "stdin" ("hallo\nballo") Right "ballo" --- snap --- Besides these two attempts explicitly spelled out I've made quite a few others, but none of them did the trick. The documentation for 'try' says that it'll only consume input upon success, but why doesn't it work w/ 'many'? I know about the Prelude-functions unlines, lines etc., but they don't really help, since linep should be used within another parser of mine. I am using Parsec as of Jan 25, 2001 (the version included w/ ghc 5.02). Any hints/solutions/... would be greatly appreciated! Bye -- Till

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Re: String type in Socket I/O
by dominic.j.steinitz＠britishairways.com 08 Apr '02

08 Apr '02

Having written a Haskell LDAP interface, this is something that worried me but I never got to the bottom of. I've cross-posted this to haskell (hopefully the right place). There was some discussion of replacing Char by a type for raw bytes / octets but I'm not sure what happened to it. Dominic. "Warrick Gray" <oinutter(a)hotmail.com>@haskell.org on 07/04/2002 13:31:41 Sent by: libraries-admin(a)haskell.org To: libraries cc: bcc: Subject: String type in Socket I/O Hi all, I am writing an HTTP client-side library, using the SocketPrim library. During the implementation of Base64 encode/decode I began to have some doubts over the use of the Char type for socket I/O. As far as I can tell, "sendTo" and "recvFrom" are simply handles on the underlying OS calls. My winsock2.h file tells me the data passed into and received from these functions are C style chars, 8 bits each. In unix these functions (sys/sockets.h) appear to use a C void pointer. Finally I notice that the Haskell98 report defines Haskell Char as a Unicode char (which I figure isn't guaranteed 8 bits). So I am curious, what happens when I send these unicode Haskell chars to the SocketPrim.sendTo function? My current guess is that the low 8 bits of each Char become a C style char. My base64 encoding and decoding functions sort of make this assumption, by ripping out the low 8 bits of chars before encoding this binary representation (3x8bit chars become 4x6bit base64 chars). So far everything works fine, but is this approach going to break in the near future? What I would like to see are socket functions that do not introduce this extra level of binary indirection, perhaps using a ByteArray, or Word8 (as I see has previously been discussed - http://www.haskell.org/pipermail/libraries/2001-August/000482.html) How realistic is this? Warrick. _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. _______________________________________________ Libraries mailing list Libraries(a)haskell.org http://www.haskell.org/mailman/listinfo/libraries ------------------------------------------------------------------------------------------------- Save time by using an eTicket and our Self-Service Check-in Kiosks. For more information go to http://www.britishairways.com/eservice1

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ANNOUNCE: Object I/O released
by Krasimir Angelov 08 Apr '02

08 Apr '02

The first release, 0.1, of Object I/O is now available. The Object I/O for Haskell library is a port of standard Clean Object I/O library. The general structure of the Haskell version is inherited from the original library but there are also few differences provoked from the languages differences. Object I/O allows Haskell programmers to build rich graphical user interface. This release support only Windows platform. Features include: * Modal and nonmodal dialogs * Nonmodal resizeable windows * Toolbars and menus * Various kind of controls and possibility to build custom controls * Layout manager for controls * Timers. The timer simplifies building of little games. See examples. * Support for file opening with "drag & drop" Quick reference is available from: <A href="http://free.top.bg/ka2_mail/objectio-ref.zip"> http://free.top.bg/ka2_mail/objectio-ref.zip</A> Binary package compiled with GHC-5.02.1 <A href="http://free.top.bg/ka2_mail/objectio.zip"> http://free.top.bg/ka2_mail/objectio.zip</A> Examples <A href="http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/hslibs/object-io/Examples">http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/hslibs/object-io/Examples</A> Source package <A href="http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/hslibs/object-io">http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/hslibs/object-io</A> __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/

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2nd Call for Papers: 7th ERCIM FMICS (Malaga, Spain) July 12-13, 2002
by Hubert Garavel 07 Apr '02

07 Apr '02

[ Apologies for multiple copies ] ****************************************************************************** * * --- CALL FOR PAPERS --- * * 7th International Workshop on Formal Methods for Industrial Critical Systems * (FMICS 02) * * University of Málaga (Spain) * July 12-13, 2002 * Colocated with the 29th ICALP conference * * http://www.inrialpes.fr/vasy/fmics/workshop-7 * ****************************************************************************** *** SCOPE OF THE WORKSHOP *** The aim of the FMICS workshops is to provide a forum for researchers who are interested in the development and application of formal methods in industry. In particular, these workshops should bring together scientists who are active in the area of formal methods and interested in exchanging their experiences in the industrial usage of these methods. They also aim at the promotion of research and development for the improvement of formal methods and tools for industrial applications. Topics include, but are not restricted to: - Tools for the design and development of formal descriptions - Verification and validation of complex, distributed, real-time systems and embedded systems - Verification and validation methods that aim at circumventing shortcomings of existing methods in respect to their industrial applicability - Formal methods based conformance, interoperability and performance testing - Case studies and project reports on formal methods related projects with industrial participation (e.g. safety critical systems, mobile systems, object-based distributed systems) - Application of formal methods in standardization and industrial forums Previous Workshops of the ERCIM working group on formal methods for Industrial Critical Systems were held in Oxford (March 1996), Cesena (July 1997), Amsterdam (May 1998),Trento (July 1999), Berlin (April 2000), and Paris (July 2001). The Seventh International Workshop on Formal Methods for Industrial Critical Systems (FMICS 02) will take place in Málaga on July 12-13, 2002, in co-location with the 29th ICALP conference. *** INVITED SPEAKERS *** Andrew Gordon (Microsoft Research Cambridge, UK) Wang Yi (Uppsala University, Sweden) *** PROGRAMME COMMITTEE *** T. Arts (Ericsson, S) M. Bernardo (Univ. of Urbino, I) R. Cleaveland (SUNY and Reactive Systems, USA), co-chair W.J. Fokkink (CWI, NL) H. Garavel (INRIA Rhone-Alpes, F), co-chair S. Gnesi (CNR/IEI Pisa, I) P. Godefroid (Bell Labs, USA) H. Hermanns (Univ. Twente, NL) T. Margaria (METAFrame Technologies, D) P. Merino Gómez (Univ. Málaga, E), organization chair I. Schieferdecker (GMD Berlin, D) S. Schneider (Royal Holloway, University of London, UK) M. Sighireanu (University of Paris-7 Jussieu, F) R. de Simone (INRIA Sophia Antipolis, F) U. Ultes-Nitsche (University of Southampton, UK) A. Valmari (Tampere University of Technology, Fi) W. Visser (RIACS/NASA Ames, USA) *** LOCAL ORGANISING COMMITTEE *** All the local organising committee members belong to the Software Engineering Group of the University of Málaga. M. del Mar Gallardo P. López J. Martínez P. Merino *** IMPORTANT DATES *** => Deadline for submission: April 21, 2002 => Accept/Reject notification: May 15, 2002 => Final manuscript: June 12, 2002 => Tool demo proposals: May 3, 2002 (contact Hubert.Garavel(a)inrialpes.fr) => Workshop: July 12-13, 2002 *** SUBMISSIONS (updated February 11, 2002) *** Papers submitted to FMICS 02 must be in English and present original research that is unpublished and not submitted for publication elsewhere. The proceedings of the workshop will be published physically by the University of Málaga and will appear in the ENTCS series (Electronic Notes in Theoretical Computer Science). This series is published online using the facilities of Elsevier Science and is reviewed by both the Mathematical Reviews of the AMS and the ACM's Computing Reviews. Additionally, the Table of Contents and Abstracts are published in the journal Theoretical Computer Science as they appear online. Papers submitted to FMICS 02 should be between 10 and 16 pages, with a clear abstract and list of keywords. Since papers published in ENTCS must be formatted uniformly, it is advised to follow the instructions for authors of papers in ENTCS volumes (http://math.tulane.edu/~entcs) Papers should be submitted by e-mail to fmics02(a)inrialpes.fr. The format should be either standard PostScript (printable by any PostScript device) or PDF (Adobe's Portable Document Format). In both cases, one should use only vectorial ("Type 1") fonts and not bitmap fonts. In case of acceptance of a paper at least one author must present the contribution at the workshop, otherwise it will be removed from the list of publications. It is expected that a special journal issue will be devoted to a sampling of papers presented at FMICS 2002. Since 1998, six special issues related to FMICS have been published (or will appear) in prestigious journals such as Formal Aspects of Computing, Formal Methods in System Design, and Science of Computer Programming. *** FURTHER INFORMATION *** The workshop will take place at University of Málaga in co-location with the 29th ICALP conference. Participants should register in advance. A minimal registration fee is charged for participants proceedings, lunch and refreshments. Further information on FMICS 02 can be obtained at the workshop web site: http://www.inrialpes.fr/vasy/fmics/workshop-7 Please indicate your interest to receive actual news via email by sending your address to fmics02(a)inrialpes.fr.

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FMCO: New Symposium on Objects and Components
by F.S.de.Boer＠cwi.nl 05 Apr '02

05 Apr '02

We apologize for the reception of multiple copies. **************************CALL FOR PARTICIPATIONT****************************** First International Symposium on FORMAL METHODS FOR OBJECTS AND COMPONENTS (FMCO 2002) http://www.liacs.nl/~marcello/FMCO/fmco02.html DATES November 5-8, 2002 PLACE Leiden, The Netherlands INVITED SPEAKERS Tutorials Manfred Broy (Technical University of Munchen) Werner Damm (University of Oldenburg) David Harel (The Weizmann Institute of Science) Bertrand Meyer (ETH Zurich and ISE) Perdita Stevens (Edinburgh University) Clemens Szyperski (Microsoft Research) Jos Warmer (Klasse Objecten) Technical presentations Erika Abraham-Mumm (CAU) Farhad Arbab (CWI) David Garlan (Carnegie Mellon University) Leslie Lamport (Microsoft Research) John Hatcliff (Kansas State University) Jozef Hooman (University of Nijmegen) Paul Klint (CWI) Bart Jacobs (University of Nijmegen) Gary Leavens (Iowa State University) Rustan Leino (Microsoft Research) Ugo Montanari (Pisa University) Oscar Nierstrasz (University of Berne) Amir Pnueli (The Weizmann Institute of Science) Bernhard Rumpe (Technical University of Munchen) Ernst-Ruediger Olderog (University of Oldenburg) Emil Sekerinski (McMaster University) Kaisa Sere (Turku University) Joseph Sifakis (Verimag) Martin Wirsing (Technical University of Munchen) THEME Large and complex software systems provide the necessary infrastucture in all industries today. In order to construct such large systems in a systematic manner, the focus in the development methodologies has switched in the last two decades from functional issues to structural issues: both data and functions are encapsulated into software units which are integrated into large systems by means of various techniques supporting reusability and modifiability. This encapsulation principle is essential to both the object-oriented and the more recent component-based sofware engineering paradigms. Formal methods have been applied successfully to the verification of medium-sized programs in protocol and hardware design. However, their application to the development of large systems requires more emphasis on specification, modeling and validation techniques supporting the concepts of reusability and modifiability, and their implementation in new extensions of existing programming languages like Java. The objective of this symposium is to bring together researchers and practioners in the areas of software engineering and formal methods to discuss the concepts of reusability and modifiability in component-based and object-oriented software systems. The following issues related to modifiability and reusability in components and objects will be discussed by leading experts in the fields of Formal Methods and Software Engineering: - Specification - Verification - Validation - Modeling techniques - Architectures - Programming languages - Semantics - Type theory - Design methodology - Compositionality - Refinement - Theorem-proving - Model checking - Tools FORMAT The Symposium is a four days event in the style of the former REX workshops, organized to provide an atmosphere that fosters collaborative work, discussions and interation. Lectures are given by the invited speakers listed above. Participation is limited to about 80 people. The program consists of invited tutorials and more technical presentations, and contains an exquisite social event. Both tutorial and technical contributions will be published after the workshop in a proceedings of Lecture Notes in Computer Science by Springer-Verlag. ORGANISING COMMITTEE F.S. de Boer (CWI) M.M. Bonsangue (LIACS-Leiden University) S. Graf (Verimag) W.-P. de Roever (CAU) *****************************PATICIPATION*********************************** For more information about participation and registration see the FMCO site http://www.liacs.nl/~marcello/FMCO/fmco02.html. For further information consult F.S. de Boer (frb(a)cwi.nl) or M.M. Bonsangu (marcello(a)liacs.nl)

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CFP: TIP'02 Workshop on Types in Programming
by Workshop on Types in Programming 05 Apr '02

05 Apr '02

NEWS: ENTCS issue planned for proceedings Final Call for Papers Workshop on Types in Programming (TIP'02) Dagstuhl, Germany, July 9, 2002 Colocated with MPC'02 http://www.informatik.uni-freiburg.de/~thiemann/tip02/ Modern programming languages rely on type systems with static type checking to detect common errors at compile time. While the benefits of statically checked type systems have long been recognized, there are some areas where the type systems of modern programming languages are not expressive enough. Some interesting programs will always be rejected, despite their semantical soundness. There are several remedies to this situation, ranging from dependent types (where types may contain values) through intersection types to types with modalities. These systems are well-investigated from a theoretical point of view by logicians and type theorists. However, the impact of these developments on practical programming has been small, partly because they are trading simplicity against expressivity. The objective of the workshop is to make researchers in programming languages aware of new developments and research directions on the theory side while at the same time pointing out problems arising in practical uses to theorists. Technical topics include, but are not limited to: * Type systems in all variants: polymorphic, dependent, intersection, modal, linear. * Annotated type systems. * Low-level type systems. * Advanced uses and applications. Original results that bear on these and related topics are solicited. Papers investigating novel uses, applications, and shortcomings of type systems in the broadest sense are especially encouraged. Authors concerned about the appropriateness of a topic are welcome to consult with the program chairs at <URL:mailto:tip02@informatik.uni-freiburg.de> prior to submission. An extended abstract should be submitted electronically to <URL:mailto:tip02@informatik.uni-freiburg.de>. Acceptable formats are PostScript or PDF, viewable by gv. Submissions should not exceed 5000 words, excluding bibliography and figures. Submitted papers will be judged on significance, relevance, correctness, originality, and clarity. They should include a clear identification of what has been accomplished and why it is significant. Informal workshop proceedings will appear as a technical report at INRIA. It is planned to publish an ENTCS volume <URL:http://www.elsevier.nl/locate/entcs> with selected works, refereed to conference standard, after the workshop. Deadline for submission: 27 April 2002 Notification: 1 June 2002 Final papers due: 29 June 2002 Program Committee: Gilles Barthe, INRIA Sophia-Antipolis, France [co-chair] Jacques Garrigue, Kyoto University, Japan Eugenio Moggi, University of Genova, Italy Zhong Shao, Yale University, USA Peter Thiemann, Universität Freiburg, Germany [co-chair] Joe Wells, Heriot-Watt University, Edinburgh, Scotland

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minimumBy and maximumBy
by Koen Claessen 05 Apr '02

05 Apr '02

Dear all, Has anyone ever noticed that the functions 'maximumBy' and 'minimumBy' from the Prelude are really the same function? Both are defined as: maximumBy, minimumBy :: (a -> a -> a) -> [a] -> a maximumBy max xs = foldl1 max xs minimumBy min xs = foldl1 min xs Is there any reason for this? Regards, /Koen. -- Koen Claessen http://www.cs.chalmers.se/~koen Chalmers University, Gothenburg, Sweden.

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RE: explicitly quantified classes in functions
by Simon Peyton-Jones 05 Apr '02

05 Apr '02

| Ah yes, silly me. What I had in mind, I suppose, was | something more along the lines of: | | foo :: Double -> (exists q . Foo q => q) Correct. Currently you can only express this by wrapping the existential in a constructor: data R = forall q. Foo q => MkR q foo :: Double -> R Mark Shields and I wrote a paper about doing more fully fledged existentials, but it's quite a significant chunk of work to implement. http://research.microsoft.com/~simonpj/Papers/first-class-modules Simon

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RE: functional programming contest
by Simon Peyton-Jones 05 Apr '02

05 Apr '02

Yes, and there will be one this year too. Tim Sheard is organising it. Simon | -----Original Message----- | From: Tom Pledger [mailto:Tom.Pledger@peace.com] | Sent: 05 April 2002 04:03 | To: haskell(a)haskell.org | Subject: functional programming contest | | | Andre W B Furtado writes: | | I was visiting http://www.ai.mit.edu/extra/icfp-contest/ | and noticed that | there was a functional programming | contest in ICFP 98. I'd like to know if | there are any | periodic functional progamming contests around the world, | such | as the ACM contest for the C language. | | There's been one associated with ICFP every year from 1998 | onward. Most recently: | http://cristal.inria.fr/ICFP2001/prog-contest (I can't get through to check that URL at the moment, but it did work OK last July.) _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

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functional programming contest
by Andre W B Furtado 05 Apr '02

05 Apr '02

I was visiting http://www.ai.mit.edu/extra/icfp-contest/ and noticed that there was a functional programming contest in ICFP 98. I'd like to know if there are any periodic functional progamming contests around the world, such as the ACM contest for the C language. -- Andre

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