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Type inference for arbitrary rank types
by Edsko de Vries 23 Jun '06

23 Jun '06

Hi, I am currently studying the paper "Practical Type Inference for Arbitrary Rank Types" by Simon Peyton Jones and Mark Shields, and I've been wondering about the final version of the typing rules (figure 7, "Bidirectional version of Odersky-Laufer") (although I suppose the question is slightly more general than this figure). In this figure, there are rules for annotated abstractions (AABS1 and AABS2) and annotated terms (ANNOT). What I'm wondering about: are the rules AABS1 and AABS2 really necessary? As in, if you would remove those two rules, does there exist a program that can be typed with the original set of rules than cannot be typed with the set of rules with AABS1/2 removed? It seems to me that any program that can be typed using AABS1/2, can also be typed with ANNOT. More importantly, in the absence of lexically scoped type variables, a type such as forall a. (forall b. (a, b) -> (b, a)) -> [a] -> [a] (*) (the example given on page 11, section 4.1 in the paper) cannot even be typed using AABS1/2, but must be typed with ANNOT. Perhaps I am missing something here though, because in Odersky and Laufer's original paper, they do not do "local type inference" (they don't specify a bidirectional version), which would make type (*) impossible to specify in their original system? Thanks, Edsko

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FOOL/WOOD '07 Call for papers
by Simon Marlow 23 Jun '06

23 Jun '06

[ posting on behalf of John Reppy <jhr(a)cs.uchicago.edu> ] Call For Papers 2007 International Workshop on Foundations and Developments of Object-Oriented Languages (FOOL/WOOD '07) Sponsored by ACM SIGPLAN Saturday, 20 January 2007 Nice, France Following POPL '07 http://foolwood07.cs.uchicago.edu Deadlines Submissions: Friday, 6 October 2006, 12:00 noon CDT (19:00 UTC) Notifications: Friday, 24 November 2006 Final versions: Friday, 22 December 2006 Workshop Description The search for sound principles for object-oriented languages has given rise to much work during the past two decades, leading to a better understanding of the key concepts of object-oriented languages and to important developments in type theory, semantics, program verification, and program development. The merger of the FOOL and WOOD workshops is intended to bring together researchers to share new ideas and results in these areas. The second joint workshop, FOOL/WOOD '07, will be held in Nice, France on Saturday, 20 January 2007, the day after POPL. Submissions for this event are invited in the general area of foundations of object-oriented languages and program analysis. Topics of interest include language semantics, type systems, program analysis and verification, formal calculi, concurrent and distributed languages, database languages, and language-based security issues. Papers are welcome to include formal descriptions and proofs, but these are not required; the key consideration is that papers should present novel and valuable ideas or experiences. The main focus in selecting workshop contributions will be the intrinsic interest and timeliness of the work, so authors are encouraged to submit polished descriptions of work in progress as well as papers describing completed projects. A web page will be created and made available as an informal electronic proceedings. Historically, presentation at FOOL/WOOD does not count as prior publication, and many of the results presented at FOOL/WOOD have later been published ECOOP, OOPSLA, POPL, and other conferences. Submission Instructions We solicit submissions on original research not previously published or currently submitted for publication elsewhere. The program chair should be informed of any related submissions; see the ACM SIGPLAN Republication Policy. Submissions should be PDF or PostScript in standard SIGPLAN 9pt conference format for a US-letter size page; templates are available at http://www.acm.org/sigs/sigplan/authorInformation.htm While submissions can be up to 12 pages, shorter papers describing promising preliminary work are also encouraged. Program Chair John Reppy (University of Chicago) e-mail: foolwood07 at mailman.cs.uchicago.edu Program Committee Derek Dreyer (Toyota Technological Institute at Chicago) Erik Ernst (University of Aarhus) Atsushi Igarashi (Kyoto University) Rustan Leino (Microsoft) Luigi Liquori (INRIA Sophia Antipolis) Todd Millstein (University of California - Los Angeles) David Walker (Princeton University) Elena Zucca (University of Genova) Steering Committee Viviana Bono (Universita di Torino) Michele Bugliesi (Universita Ca' Foscari) Sophia Drossopoulou (Imperial College) Kathleen Fisher (AT&T Labs) [Chair] Martin Odersky (Ecole Polytechnique Federale de Lausanne) Benjamin Pierce (University of Pennsylvania) Philip Wadler (University of Edinburgh)

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Finding the length of a String in bytes
by David House 22 Jun '06

22 Jun '06

Hi there. I recently needed to add a Content-Length header to my HTTP request forged with Network.HTTP [1]. However, this needs to be the length of the body content in bytes, not characters. Without assuming the characters will all be ASCII, is there an easy way of doing this? length seems to have the correct results, but I'm uneasy about relying on this. Any comments? -- -David House, dmhouse(a)gmail.com

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CFP: 2nd Int'l Workshop on Automated Specification and Verification of Web Systems (WWV'06)
by Santiago Escobar 21 Jun '06

21 Jun '06

[ We apologize for multiple copies ] ******************************************************************* 2nd International Workshop on Automated Specification and Verification of Web Systems (WWV'06) Cyprus, November 15-19, 2006 (Track of ISoLA 2006) http://www.dsic.upv.es/workshops/wwv06 ******************************************************************* SCOPE The increased complexity of Web sites and the explosive growth of Web-based applications has turned their design and construction into a challenging problem. Nowadays, many companies have diverted their Web sites into interactive, completely-automated, Web-based applications (such as Amazon, on-line banking, or travel agencies) with a high complexity that requires appropriate specification and verification techniques and tools. Systematic, formal approaches to the analysis and verification can address the problems of this particular domain with automated and reliable tools that also incorporate semantic aspects. We solicit paper on formal methods and techniques applied to Web sites, Web services or Web-based applications, such as: * rule-based approaches to Web site analysis, certification, specification, verification, and optimization * formal models for describing and reasoning about Web sites * model-checking, synthesis and debugging of Web sites * abstract interpretation and program transformation applied to the semantic Web * intelligent tutoring and advisory systems for Web specifications authoring The WWV series provides a forum for researchers from the communities of Rule-based programming, Automated Software Engineering, and Web-oriented research to facilitate the cross-fertilization and the advancement of hybrid methods that combine the three areas. LOCATION WWV'06 will be held in November in Cyprus as a Special Track of the 2006 International Symposium on Leveraging Applications of Formal Methods, Verification, and Validation (ISoLA 2006). SUBMISSION PROCEDURE Submissions must be received by July 16, 2006. In addition, an ASCII version of the title and abstract must have been submitted by July 3, 2006. Submitted papers should be at most 15 pages in the Lecture Notes in Computer Science (LNCS) style. Submitted papers should include an abstract and the author's information. See the author's instructions of LNCS style at http://www.springer.de/comp/lncs/authors.html. PUBLICATION Accepted papers will be published in a preliminary proceedings volume, which will be available during the workshop. Publication of the workshop post-proceedings by IEEE Computer Society Press is envisaged. PROGRAM CO-CHAIRS Maria Alpuente (Technical University of Valencia, Spain) Moreno Falaschi (University of Siena, Italy) WORKSHOP CHAIR Santiago Escobar (Technical University of Valencia, Spain) PROGRAM COMMITTEE Jose Julio Alferes (Universidade Nova de Lisboa, Portugal) Maria Alpuente (Technical University of Valencia, Spain) Demis Ballis (University of Udine, Italy) Francois Bry (University of Munich, Germany) Santiago Escobar (Technical University of Valencia, Spain) Francois Fages (INRIA Rocquencourt, France) Moreno Falaschi (University of Siena, Italy) Gopal Gupta (University of Texas at Dallas, USA) Shriram Krishnamurthi (Brown University, USA) Tiziana Margaria (University of Potsdam, Germany) I.V. Ramakrishnan (State University of New York at Stony Brook, USA) Leon van der Torre (University of Luxembourg, Luxembourg) IMPORTANT DATES Abstract Submission July 3, 2006 Full Paper Submission July 16, 2006 Acceptance Notification September 17, 2006 Camera Ready October 15, 2006 Workshop November 15-19, 2006 (one day)

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The GHC hackathon: 14,15 September 2006, Portland
by Simon Peyton-Jones 21 Jun '06

21 Jun '06

Friends After some encouragement at last year's ICFP, Simon and I are going to run a GHC hackathon, in Portland, just before ICFP this September (14-15th). It'll be held at Galois's offices, in Beaverton; we're very grateful to Galois for hosting the meeting. The details are here: http://hackage.haskell.org/trac/ghc/wiki/Hackathon If you are interested in finding out a bit about how GHC works inside, then you should find the hackathon fun. It will certainly be informal and interactive. GHC is a 100% open-source project, and the more people that are involved the better it goes. If you think you might come, please take a look at the above page, and let us know by registering. See you soon! Simon

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Transnational Access Program at RISC
by Simon Marlow 21 Jun '06

21 Jun '06

[Posting on behalf of Temur Kutsia <Temur.Kutsia(a)risc.uni-linz.ac.at>] [Apologies if you receive multiple copies] ******************************************************** * European Commission Framework 6 Programme * * Integrated Infrastructures Initiatives * * * * Symbolic Computation in Europe (SCIEnce) * * * * TRANSNATIONAL ACCESS PROGRAM * * * * * * Research Institute for Symbolic Computation (RISC) * * Johannes Kepler University of Linz, Austria * * * ******************************************************** RISC-Linz, a research institute at the Johannes Kepler University, Austria, offers opportunities to researchers to obtain access to its infrastructure and facilities. Access is free of charge and is provided through the project SCIEnce within the 6th Framework Programme of the European Commission. What we offer ============= Free access to the infrastructure, facilities, and expertise of a world-leading center in symbolic computation. Scientific, technical, administrative, and logistic support, including travel and living expenses. Who can benefit =============== Researchers from any field of sciences who use or would like to use symbolic computation in their research. For more information and the application procedure please visit the program web page: http://www.risc.uni-linz.ac.at/research/projects/science/access/

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Would you like a job working on GHC?
by Simon Peyton-Jones 21 Jun '06

21 Jun '06

Would you like to be paid to work on GHC? The Glasgow Haskell Compiler (GHC) is now being used by so many people, on so many platforms, that at GHC HQ we've been struggling to keep up. We're delighted to say that we are now looking to hire a GHC support engineer to work with us. Here is how we envisage working together: * You would work 3-5 days a week on GHC (details flexible). * You don't need to live in Cambridge, but we would like you to visit every few months, so that we build up a face-to-face relationship. * You'll be a self-employed consultant, not a Microsoft employee. You bill us; we pay you. * The position is a one year fixed term contract in the first instance. * GHC is, and will remain, an open-source project with a BSD-style license. We are looking for help with the role of supporting GHC in the field. Specifically, here's what the job involves: * Investigating, prioritising and fixing bugs, improving the test suite * Managing the STABLE branch of the source tree * Managing the GHC release cycle * Keeping the GHC web site up to date * Answering questions from GHC users * Helping to support the open-source community that works on GHC itself We're particularly looking for someone who is experienced in a variety of operating system platforms and libraries. You should be able to deal with questions like "I try to build GHC on Solaris 2.3.4 and get `undefined symbol _readline'"; or "How do I link to DLLs on Windows?"; or "does the ByteString library in GHC 6.2.1 do XXX?". The role will not primarily involve working on GHC's core; it's the parts round the edges that you would mainly focus on. You must be able to read and write Haskell, but we don't expect that you'll need to write a great deal of Haskell code. C and 'make' experience are important too. Above all, we are looking for someone who is enthusiastic about Haskell, and fired up about the prospect of becoming a GHC expert. If you are interested, please send your CV and a statement of why you would be a good fit for the job, to our Human Resources Department at camjobop(a)microsoft.com We're happy to accept informal enquiries of course: please contact Simon Marlow (simonmar(a)microsoft.com) or Simon Peyton Jones (simonpj(a)microsoft.com) for further information. The rate of pay is dependent on qualifications and experience. It'll be fun! Simon Peyton Jones and Simon Marlow

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aosd 2007
by Oege.de.Moor＠comlab.ox.ac.uk 20 Jun '06

20 Jun '06

AOSD 2007: CALL FOR RESEARCH PAPERS 6th Conference on Aspect-Oriented Software Development http://www.aosd.net/2007/cfc/research.php >> abstract submission by September 22, 2006 << ------------------------------------------------------ The program committee especially welcomes submissions from researchers in functional programming on any topic relating to aspect-oriented extensions of Haskell (or why you don't need them!)

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Re: [Haskell] extensible records using associated types
by Barney Hilken 20 Jun '06

20 Jun '06

The implementation of records using types data N a r = N a r might well be inefficient, and I don't know enough about the workings of the compiler to see whether it could be improved by unboxing and strictness. But the real point of my post was the classes Contains, Lacks and Disjoint which give you extensibility. To give another example, if Haskell had non-extensible records {N1 = x1, ..., Nn = xn} of type {N1 :: a1, ..., Nn :: an} we could use the same technique to make them extensible. Assume we can represent the field names N somehow as values (N :: Constructor N). Then we can define instances of the form instance Contains Nj {N1 :: a1, ..., Nj :: aj, ..., Nn :: an} where type Project Nj {N1 :: a1, ..., Nj :: aj, ..., Nn :: an} = aj type Delete Nj {N1 :: a1, ..., Nj :: aj, ..., Nn :: an} = {N1 :: a1, ..., Nn :: an} project Nj {N1 = x1, ..., Nj = xj, ..., Nn = xn} = xj delete Nj {N1 = x1, ..., Nj = xj, ..., Nn = xn} = {N1 = x1, ..., Nn = xn} instance Lacks M {N1 :: a1, ..., Nn :: an} where type Extend M a {N1 :: a1, ..., Nn :: an} = {M :: a, N1 :: a1, ..., Nn :: an} type extend M x {N1 = x1, ..., Nn = xn} = {M = x, N1 = x1, ..., Nn = xn} instance Disjoint {N1 :: a1, ..., Nn :: an} {M1 :: b1, ..., Mm :: bm} where type Union {N1 :: a1, ..., Nn :: an} {M1 :: b1, ..., Mm :: bm} = {N1 :: a1, ..., Nn :: an, M1 :: b1, ..., Mm :: bm} union {N1 = x1, ..., Nn = xn} {M1 = y1, ..., Mm = ym} = {N1 = x1, ..., Nn = xn, M1 = y1, ..., Mm = ym} Of course, there are a lot of these (exponential in the number of field names!) so you don't really want to generate them all. But exactly the same classes (modulo the definition of Constructor, which should be hidden anyway) give you extensibility, so any code you write will work with either implementation. Barney.

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CPSec workshop extended deadline!
by Stefano Bistarelli 20 Jun '06

20 Jun '06

-------------------------------------------------------------------- EXTENDED DEADLINE: July 1 Call for Papers: CPSec 2006 2nd International Workshop on Applications of Constraint Satisfaction and Programming to Computer Security September 25, 2006 Nantes, France Held in conjunction with 12th International Conference on Principles and Practice of Constraint Programming, CP2006 http://www.sci.unich.it/~bista/organizing/cpsec/ -------------------------------------------------------------------- Constraint Satisfaction and Programming is emerging as an effective and practical approach for solving large complex problems. It offers a significant body of successful techniques for verifying system properties. Recently, researchers have begun using advances in constraint programming and solving to solve security problems, with success. This workshop seeks to act as a catalyst for this emerging area by exploring the challenges and the potential that these techniques may offer when applied to security problems. The use of Constraint Satisfaction and Programming to address security problems is recent, and it has already produced a number of novel solutions and insights. For example, constraints have been successfully used in the the analysis of security protocols, the development of access control models and mechanisms, firewall configuration and secure system configuration in general. Workshop topics include (but are not limited to): Access Control Database Security Security Trade-offs Information Flow Integrity Configuration Management Security Models Reliability Security Protocols Intrusion Detection Applications Risk Analysis Trust Software Security Trust Negotiation Submissions The workshop aim is to provide a forum where researchers currently working in the area of security and constraints can discuss their most recent ideas and developments and think together about the most promising new directions. Therefore we encourage the presentation of work in progress or on specialized aspects of the area. Papers that bridge the gap between theory and practice are especially welcome. Prospective attendees can submit a paper, which can be up to 15 pages in length. We encourage authors to submit papers electronically in postscript or pdf format. Papers should be formatted using the Lecture Notes in Computer Science (LNCS) style. At least one author of each accepted submission must attend the workshop, and all participants must pay the workshop fee. Please send your submissions by email to stefano.bistarelli(a)iit.cnr.it using the subject line "cpsec-2006 Workshop Submission". Important Dates Paper Submission deadline: July 1 (extended deadline) Notification of acceptance: July 22th Early registration deadline: August 1st Camera-ready version deadline: August 5th Workshop Date: September 25, 2006. Workshop Organizers: Giampaolo Bella (Universit`a di Catania, Italy) Stefano Bistarelli (Università degli studi "G. D'Annunzio" di Chieti-Pescara & C.N.R. Pisa, Italy) Simon Foley (University College Cork, Ireland) Fred Spiessens (University College Cork, Ireland) Program Committee: Giampaolo Bella, Catania Fabio Martinelli, CNR Stefano Bistarelli, Pescara and CNR Barry O'Sullivan, Cork Yannick Chevalier, IRIT Justin Pearson, Uppsala Giorgio Delzanno, Genova Michael Rusinowich, LORIA Alessandra Di Pierro, Pisa Fred Spiessens, Cork Fabio Fioravanti, Pescara, Vitaly Shmatikov, Texas Simon Foley, Cork Frank D. Valencia, CNRS John Herbert, Cork Luca Vigano, Zurich Ralf Küsters, Kiel Duminda Wijesekera, GMU Herbert Wiklicky, Imperial

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