April 2002 - Haskell - Haskell.org

Feeling Old? We Can Help!
by unknown＠example.com 15 Apr '02

15 Apr '02

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HC&AR (May edition) - call for contacts and contributions
by C.Reinke 15 Apr '02

15 Apr '02

Dear fellow Haskeller, it is time again - for contributions to the second edition of the Haskell Communities and Activities Report http://www.haskell.org/communities/ The current plan is to get contributions in by the end of April, and to get the collective report out early next month (*). The general idea is to update all existing summaries, to drop any topics that didn't have any activity for two consecutive 6-month periods, and to add any new developments or topics for which no-one contributed summaries to the first edition, while trying to keep the whole under 25 pages. As you can see on the report's home page, many of last time's contributors have already volunteered to provide updates of their reports, including coverage of the major Haskell implementations and Report Addenda. But where you don't yet see contacts listed for your own subject of interest, you are 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 would be between 1 and 3 paragraphs (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,..). New suggestions for current hot topics, activities, projects, .. are welcome - especially with names and addresses of potential contacts. Two particular new suggestions I'd like to try this time are appended below. Thanks, Claus (*) Last time's experience showed that it takes an arbitrary number of weeks to write a nice summary in the last hour, so I hope that 2 weeks give enough flexibility to find a spare hour, or to coordinate the summary with any planned releases. ---------------------------------------------- Two new suggestions: 1 Applications: "what are you using Haskell for?" The implementation mailing lists are full of people sending in bug reports and feature suggestions, stretching the implementations to their limits. Judging from the "reduced" examples sent in to demonstrate problems, there must be quite a few Haskell applications out there that haven't been announced anywhere (probably because Haskell is "just" the tool, not the focus of those projects). If you're one of those serious Haskell users, why not write a sentence or two about your application? We'd be particularly interested in your experience with the existing tools (e.g., that all-time-favourite: how difficult was it to tune the resource usage to your needs, after you got your application working? Which tools/libraries where useful to you? What is missing?). 2 Project pings: "anyone still working on this?" There are numerous projects out there that don't add new features to their software releases every week, but are steadily working towards longer-term goals while keeping their software releases maintained and up-to-date. The people involved often say "We don't really have to report anything new, so we won't report anything.". However, most of you out there know that there is a *huge* difference between projects and software in silent maintenance mode (i.e., actively being worked on) and those that die the silent death of "been there, published that, let's move on". If you are the contact person for a project/software of the former kind, and you just want to reassure Haskellers that your stuff is still alive and kicking, send me a brief "ping", and I'll try to include a list of those pings, with contact addresses (as proofs of liveness), in the upcoming report.

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help need
by Benny 15 Apr '02

15 Apr '02

type Poly = [Float] addPoly::Poly->Poly->Poly addPoly x y = zipWith (+) x y instance (Float a) => Num (Poly a) where x + y = addPoly x y I got the "Cannot use type synonym in instance head" error message when I was trying to compile the above code. Can you tell me why and how to solve it? Cheers Benny

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"do" notation and ">>"
by Simon Peyton-Jones 15 Apr '02

15 Apr '02

Folks Following a good deal of email I now propose to DO NOTHING to the rules defining do-notation in the Haskell 98 Report. That means that GHC and Hugs, and nhc perhaps, should change so that they actually implement the do-notation translation rule do {e ; stmts} = e >> do {stmts} using (>>) and not (>>=). >From my reading of the email, some people will agree strongly, and no one will disagree strongly. I suppose I could be wrong about this, though. Simon

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about downloading
by walter blanchard 14 Apr '02

14 Apr '02

please,where can I download a version of Haskell? Thank you --------------------------------- Yahoo! Mail -- Une adresse @yahoo.fr gratuite et en français !

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about downloading
by julie madec 14 Apr '02

14 Apr '02

where can I download a version of Haskell? Thank you

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Lexing character literals in H98
by Sven Panne 14 Apr '02

14 Apr '02

Yet another H98 question, this time regarding the module Char: Is it a deliberate design decision that readLitChar handles decimal, octal, and hex escapes, but lexLitChar handles only decimal ones? It looks more like an oversight to me... Another question is if the uppercase variants '\O...' and '\X...' should be forbidden explicitly. Current implementations seem to differ in this aspect. Cheers, S.

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THEORETICAL COMPUTER SCIENCE '02 - Accepted papers
by Michel Barbeau 13 Apr '02

13 Apr '02

-- Michel Barbeau School of Computer Science, Carleton University 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6 Phone: (613) 520-2600 x 1644 Fax: (613) 520-4334 �� 2nd IFIP International Conference on �� THEORETICAL COMPUTER SCIENCE �� (TCS 2002) �� Montreal, August 25-30, 2002 �� co-sponsored by� EATCS and ACM SIGACT �(http://www.scs.carleton.ca/~santoro/TCS2002/indexTCS2002.html) �� ==========================3D=========================3D===== ========================3D=========================3D== TRACK A - Algorithms, Complexity, Models of Computations ==========================3D=========================3D -------------------------------- Jochen Alber, Jiri Fiala Geometric Separation and Exact Solutions for the Parameterized Independent Set Problem on Disk Graphs Nikhil Bansal, Zhen Liu, Arvind Sankar Bin-Packing with Fragile Objects S. Bespamyatnikh, B. Bhattacharya, D. Kirkpatrick, M. Segal Lower and upper bounds for tracking mobile servers Alina Beygelzimer, Mitsunori Ogihara On the enumerability of the determinant and the rank Beate Bollig, Stephan Waack, Philipp Woelfel Parity Graph-driven Read-Once Branching Programs and an Exponential Lower Bound for Integer Multiplication Vasco Brattka, Martin Ziegler Computability of Linear Equations G. Calinescu. I.I. Mandoiu, A. Zelikovsky Symmetric connectivity with minimum power consumption in radio networks Olivier Carton, V�ronique Bruy�re Hierarchy among Automata on Linear Orderings Z. Chen A Modified Recursive Triangular Factorization� for Cauchy-like Systems of Linear Equations M. Cieliebak, T. Erlebach, Z. Liptak, J. Stoye, E. Welzl Algorithmic complexity of protein identification: searching in weighted strings Alessandro Dal Palu`, Enrico Pontelli, Desh Ranjan An Efficient Parallel Pointer Machine Algorithm for Nearest-Common Ancestor Problem M. Duflot, L. Fribourg, C. Picaronny Randomized dining philosophers without fairness assumption Alon Efrat, Sariel Ar-Peled Locating guards in Art Galleries Leszek Gasieniec, Igor Potapov Gossiping with Single Messages in Radio Networks Nicolas Hanusse, Dimitris Kavvadias, Evangelos Kranakis, Danny Krizanc Memoryless Search Algorithms in a Network with Faulty Advice Lane A. Hemaspaandra, Mayur Thakur Rice-Style Theorems in Complexity Theory Matthew Hertz, Neil Immerman,� J. Eliot,� B. Moss Framework for Analyzing Garbage Collection Christopher M. Homan, Mayur Thakur One-Way Permutations and Self-Witnessing Languages Klaus Jansen, Hu Zhang Approximation Algorithms for General Packing Problems with Modified Logarithmic Potential Function Gregory Lafitte On randomness and infinity A. Pagourtzis, P. Penna, K. Schlude, K. Steinhofel, D.S. Taylor, P. Widmayer Server placements, roman domination and other dominating set variants B. S. Panda, Sajal K. Das A Linear Time Algorithm for Finding Tree 3-Spanner on 2-Trees Joerg Rothe, Holger Spakowski, Joerg Vogel Exact Complexity of Exact-Four-Colorability and of the Winner Problem for Young Elections Paolo Santi, Douglas M. Blough, Mauro Leoncini, Giovanni Resta On the Symmetric Range Assignment Problem in Wireless Ad Hoc Networks Tomoyuki Yamakami Quantum NP and Quantum Operator Marius Zimand Probabilistically checkable proofs the easy way ==========================3D=========================3D TRACK B - Logic, Semantics, Specification and Verification ==========================3D=========================3D Patrick Baillot Checking Polynomial Time Complexity with Types Chiara Braghin, Agostino Cortesi, Riccardo Focardi, Steffen van Bakel Boundary Inference for Enforcing Security Policies in Mobile Ambients Hana Chockler, Orna Kupferman Coverage of Implementations by Simulating Specifications Giovanni Conforti, Orlando Ferrara, Giorgio Ghelli TQL Algebra and its Implementation Dino Distefano, Arend Rensink, Joost-Pieter Katoen Model Checking Birth and Death Matthew Fluet, Riccardo Pucella Phantom Types and Subtyping Rachid Guerraoui, Petr Kouznetsov On the Weakest Failure Detector for Non-Blocking Atomic Commit Martin Hyland, Gordon Plotkin, John Power Combining Computational Effects: commutativity & sum Salvatore La Torre, Supratik Mukhopadhyay, Aniello Murano Optimal-Reachability and Control for Acyclic Weighted Timed Automata Daniel Leivant Substructural Verification and Computational Feasibility Stephane Lengrand, Dan Dougherty, Pierre Lescanne An Improved System of Intersection Types for Explicit Substitutions Aline Brum Loreto, Laira Vieira Toscani, Leila Ribeiro Decidability and Tractability of a Problem in Object-Based Graph Grammars Fabio Martinelli About Compositional Analysis of� Pi-Calculus Processes Catuscia Palamidessi, Oltea Milhaela Herescu A Randomized Encoding of the Pi-Calculus with Mixed Choice I.C.C. Phillips, M.G. Vigliotti On Reduction Semantics for the Push and Pull Ambient� Calculus Alan Schmitt Safe Dynamic Binding in the Join Calculus Olivier Serre Vectorial Languages and Linear Temporal Logic Scott D. Stoller A Bound on Attacks on Authentication Protocols Xiaogang Zhang, John Potter Responsive Bisimulation

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"Introducing Parallelism in a Lazy Functional Language"
by Hal Daume III 13 Apr '02

13 Apr '02

Hey, I know this isn't the official point of this mailing list, but I'm working on something related to the paper mentioned in the subject (by Nathan Charles). I'm trying to find more information about it, but unfortunately it seems that Nathan has left York. Does anyone know where I could find him? -- Hal Daume III "Computer science is no more about computers | hdaume(a)isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

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Re: Confused about seq and forms.
by Jay Cox 13 Apr '02

13 Apr '02

On Fri, 12 Apr 2002, Bernard James POPE wrote: <snip> > Do you have a copy of the book: The implementation of Functional Programming > Languages, by Simon Peyton Jones? > > It is sadly out of print, but most universities have copies in their libraries. > > It is one of the best references that I know of. > > page 198 of that book has what you want to know. > > Cheers, > Bernie. Just to pass it along in case somebody else wants the reference. I'm a bit suprised why you only replied to me. The message part not included was as much educational to me as Janis Janis Voigtlaender's message. I'd post it all if I weren't afraid that might offend you for some reason or violate some implicit politeness law I don't know of. Thanks both, Jay Cox

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