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Haskell CVS repository now hosted by Galois
by Andy Moran 31 Aug '05

31 Aug '05

The cvs.haskell.org CVS repository, previously hosted by OGI (on glass.cse.ogi.edu) is now being hosted by Galois. The new machine is a 3.0 GHz Pentium 4 running Debian Linux (sarge); it will be actively maintained by Galois. Requests for system help should be directed to haskell-cvs(a)galois.com. Some software packages (esp. cvs and OpenSSH) have been upgraded, so some system behaviors may differ from those on the old server -- but generally the new server is a drop-in replacement for the old one. If you were previously using 129.95.44.145 or glass.cse.ogi.edu to access the CVS repository, then you should switch to cvs.haskell.org. If you were already using cvs.haskell.org, then you shouldn't notice much of a change (beyond better service). Cheers, Andy -- Andy Moran Phone: 503.626.6616, x113 Galois Connections Inc. Fax: 503.350.0833 12725 SW Millikan Way, Suite #290 http://www.galois.com Beaverton, OR 97005 moran(a)galois.com

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Haskell Weekly News: August 30, 2005
by John Goerzen 31 Aug '05

31 Aug '05

Haskell Weekly News: August 30, 2005 Greetings, and thanks for reading the fifth issue of HWN, a weekly newsletter for the Haskell community. Each Tuesday, new editions will be posted (as text) to [1]the Haskell mailing list and (as HTML) to [2]The Haskell Sequence. 1. http://www.haskell.org/mailman/listinfo/haskell 2. http://sequence.complete.org/ HWN is 1 day late this week. Pesky Real Life (TM) interfered. Sorry about that. Hopefully this won't happen again. Also, anyone that wants to help edit HWN is welcome to do so. See the contributing section at the end. New Releases * FUSE bindings. David Roundy [3]announced bindings for FUSE, the Linux library that lets people develop a filesystem using userspace code. Isaac Jones also [4]mentioned Jeremy Bobbio's FUSE bindings. * FastPackedString (FPS) packaging. Donald Bruce Stewart has extraced the FastPackedString module from darcs and [5]produced a standalone package. It is useful for working with binary data and blocks of string data. * Haskell Server Pages (HASP). Lemmih [6]announced Haskell Server Pages 0.3, an infrastructure for developing dynamic web sites. It's based around XML and the earlier work on HSP. * Cairo bindings for gtk2hs completed. Paolo Martini [7]announced that the Cairo bindings have been checked into the gtk2hs CVS repo on SourceForge. 3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/8110 4. http://article.gmane.org/gmane.comp.lang.haskell.cafe/8125 5. http://article.gmane.org/gmane.comp.lang.haskell.general/12003 6. http://thread.gmane.org/gmane.comp.lang.haskell.general/12002 7. http://sourceforge.net/mailarchive/forum.php?thread_id=8063084&forum_id=442… Discussion Parsing Binary Files. Joel Reymont began an [8]interesting discussion by asking about using Haskell to implement a parser for a binary poker protocol. Erlang has some binary pattern matching features, and there was some discussion about achieving similar results in Haskell. 8. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8111 Using STArray. Alistair Bayley asked how to use STArray to improve the performance of a program. Numerous suggestions were offered in the ensuing [9]discusion, including a link to some [10]examples on the Haskell wiki. 9. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/8091 10. http://haskell.org/hawiki/ImperativeHaskell Compiling Windows GUI Executables. Juan Carlos Arevalo Baeza [11]asked about compiling Windows GUI executables with ghc. Duncan Coutts posted a [12]link to the Gtk2Hs FAQ explaining the procedure. 11. http://thread.gmane.org/gmane.comp.lang.haskell.glasgow.user/8584 12. http://haskell.org/gtk2hs/archives/2005/06/23/hiding-the-console-on-windows/ Quotes of the Week Then Edsger Dijkstra came down from Mt. Sinai with a tablet proclaiming "Thou shalt not use GOTO; it is considered harmful"... From Chad Scherror on the haskell-cafe list: "I've been amazed at the level of effort put forth by the Haskell community as a whole to help out newcomers." About Haskell Weekly News Want to continue reading HWN? Please help us create new editions of this newsletter. Please see the [13]contributing information, or send stories to hwn -at- complete -dot- org. There is also a Darcs repository available. 13. http://sequence.complete.org/hwn-contrib

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Re: [Haskell-cafe] Monadic vs "pure" style (was: pros and cons of sta tic typing and side effects)
by Wolfgang Jeltsch 30 Aug '05

30 Aug '05

Am Dienstag, 30. August 2005 13:13 schrieb Bayley, Alistair: > [...] > I was also wondering what the disadvantages of monadic style are? Are there > compiler optimisations which are not possible with monadic code? State or StateT are monads which are implemented using ordinary pure Haskell. So, at least in the case of these two monads, you probably will enjoy the full power of optimizing. :-) Certain ST actions are implemented in Haskell, using lower level features, so certain optimizations should happen here as well. > Alistair. Best wishes, Wolfgang

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Re: [Haskell] Who brought the monad to us?
by Wolfgang Jeltsch 30 Aug '05

30 Aug '05

Am Dienstag, 30. August 2005 12:12 schrieben Sie: > Wolfgang [and Phil] > > As others have noted, Moggi had the key idea of using monads to support > the semantics of programming languages. Wadler was clearly the first to > have the amazing insight that monads could be a *programming* idiom too, > and gave several examples of their use, including lists, state monads, > continuations, and exceptions I believe. I was working with Phil at > Glasgow at the time, and I think I may have been the one to suggest > taking a monadic approach to *I/O* and FFI. But that's unimportant: > what is certain is that our co-authored paper in POPL'93 was the first > time the idea was published. > > Simon Hello Simon, thank you for your answer. Were you also the first one who had the idea to use monads for mutable variables and mutable arrays? Best wishes, Wolfgang

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ANNOUNCE: ghc-src version 0.2.0
by Lemmih 30 Aug '05

30 Aug '05

ghc-src 0.2.0 has been released. ghc-src is a Haskell parser with full support for every GHC extension. It is a refactored version of the Haskell parser used internally by GHC and is meant as a replacement for haskell-src-exts, although it might have other uses. The package is cabalized and lives under Langauge.Haskell.GHC.* in the module hierarchy. Darcs repo: http://scannedinavian.org/~lemmih/ghc-src/ -- Friendly, Lemmih

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Who brought the monad to us?
by Wolfgang Jeltsch 30 Aug '05

30 Aug '05

Hello, is it right to say that Philip Wadler was the one who invented monadic I/O or were there others who did so together with Wadler? I need this for my thesis. :-) Best wishes, Wolfgang

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How to use STArray?
by Benjamin Franksen 29 Aug '05

29 Aug '05

Hmmm, no answer on cafe, maybe someone here with a good idea? ---------- Forwarded Message ---------- On Thursday 25 August 2005 19:58, Udo Stenzel wrote: > [...] you'll need a type signature somewhere to help ghc resolve > the overloading of newArray and readArray, which is surprisingly > tricky due to the "s" that must not escape. This works: > > compute :: Int -> Int > compute n = runST ( do > arr <- newArray (-1, 1) n :: ST s (STArray s Int Int) > readArray arr 1 > ) Hello, I am fighting with a similar problem. I want to use STUArray but without committing to a fixed element type. For instance (this is not my real problem, but it's similar and easier to motivate), here is a function that appends two UArrays: A little helper first > copy :: (MArray a e m, IArray b e) => > a Int e -> Int -> b Int e -> Int -> Int -> m () > copy dest destix src srcix cnt > > | cnt <= 0 = return () > | otherwise = do > > writeArray dest destix (src ! srcix) > copy dest (destix+1) src (srcix+1) (cnt-1) and here is the append function > append :: UArray Int e -> UArray Int e -> Int -> UArray Int e > append x y low = runSTUArray (do > z <- newArray_ (low,low+len x+len y) > copy z low x (first x) (len x) > copy z (low+len x) y (first y) (len y) > return z) > where > len = rangeSize . bounds > first = fst . bounds Of course this can't work, because 'copy' needs the MArray and IArray contexts: No instance for (MArray (STUArray s) e (ST s)) arising from use of `copy' at Problem.lhs:31:7-10 [...] No instance for (IArray UArray e) arising from use of `copy' at Problem.lhs:31:7-10 [...] But now, when I add > append :: (IArray UArray e, MArray (STUArray s) e (ST s)) => ... I still get the same error message regarding the MArray constraint: No instance for (MArray (STUArray s) e (ST s)) arising from use of `copy' at Problem.lhs:31:7-10 What am I missing? That is, how and where do I have to specify the constraint? Ben

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2nd CFP: M4M-4 "Methods for Modalities"; Berlin, Dec. 1-2, 2005
by Holger Schlingloff 29 Aug '05

29 Aug '05

Apologies if you receive this CFP more than once. Please note that the submission deadline has been extended to Sep. 15th! *************************************************************************** The workshop "Methods for Modalities" (M4M) aims to bring together researchers interested in developing algorithms, verification methods and tools based on modal logics. Here the term "modal logics" is conceived broadly, including description logic, guarded fragments, conditional logic, temporal and hybrid logic, etc. To stimulate interaction and transfer of expertise, M4M will feature a number of invited talks by leading scientists, research presentations aimed at highlighting new developments, and submissions of system demonstrations. We strongly encourage young researchers and students to submit papers and posters, especially for experimental and prototypical software tools which are related to modal logics. Invited speakers: François Laroussinie, ENS Cachan and CNRS Martin Lange, Ludwig-Maximilians-Universität Wim Martens, Hasselt University Boris Motik, Universität Karlsruhe Boris Konev, University of Liverpool Uwe Scheffler, Humboldt Universität Regular papers should not exceed the length of 12 pages; short papers are up to six pages of length, and posters and tools can be presented on two pages of text. Proceedings will appear online and as a Humboldt university report. Depending on the submissions, papers may be selected to appear in a special issue of an appropriate journal. Submission is by internet or email. You can (preferrably) upload your PostScript or PDF contribution to the address http://www.easychair.org/M4M-4/submit/ or (alternatively) send it to m4m-4(a)first.fraunhofer.de. The workshop will take place in Berlin - Adlershof, Germany, which is one of the worlds largest science and technology areas, comprising twelve research institutes, six faculties of the Humboldt University of Berlin, and more than 370 high tech companies. It is hosted by FIRST, the Fraunhofer Institute of Computer Architecture and Software Technology, in collaboration with the computer science institute of Humboldt University. For more information and registration information, see the M4M homepage at http://m4m.loria.fr/ Deadline for submissions: September 15th, 2005 (extended!) Notification: October 17, 2005 Camera ready versions: November 8, 2005 Workshop dates: December 1-2, 2005 The program committee for M4M consists of Holger Schlingloff, Humboldt University / FIRST (local organizations); Carlos Areces, INRIA Lorraine; Patrick Blackburn, INRIA Lorraine; Torben Brauner, Roskilde University; Stephane Demri, ENS de Cachan; Enrico Franconi, Free University of Bolzano; Rajeev Gore, Australian National University; Ian Horrocks, University of Manchester; Joost-Pieter Katoen, RWTH Aachen; Maarten de Rijke, University of Amsterdam; Renate Schmidt, University of Manchester; and Frank Wolter, University of Liverpool.

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Parsing binary data
by Joel Reymont 28 Aug '05

28 Aug '05

Folks, I'm trying to parse chunks of binary data that arrive through a socket. There's a defined format of these chunks where the first 4 bytes are an id, then could come a Pascal (size first) string, then some more data. I'm trying to figure out how to read and write Haskell data in this format and using a socket. Would someone have examples? Thanks, Joel -- http://wagerlabs.com/tech

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UPDATE: NWPT05 Annoucenment
by jespera＠diku.dk 26 Aug '05

26 Aug '05

ANNOUNCEMENT AND CALL FOR PAPERS FOR NWPT05 =========================================== The 17th Nordic Workshop on Programming Theory http://www.diku.dk/NWPT05/ The NWPT series of annual workshops is a forum bringing together programming theorists from the Nordic and Baltic countries (but also elsewhere). This year the workshop will be held in COPENHAGEN. SCOPE Typical topics of the workshop include (but are not limited to) o Semantics of programs o Programming logics o Program verification o Formal specification of programs o Program synthesis o Program transformation and program refinement o Real-Time and hybrid systems o Modeling of concurrency o Programming methods o Tools for program construction and verification INVITED SPEAKERS o Patricia Johann, Rutgers University, USA o Carsten Schuermann, (Yale, now: IT University of Copenhagen) o Stephen Alstrup, Octoshape o Peter Sestoft, KVL, IT University of Copenhagen o Olivier Danvy, BRICS, DIKU SUBMISSIONS Authors wishing to give a talk at the workshop are requested to submit an abstract of 1-3 pages (ps or pdf, printable on A4 paper) to nwpt05(at)diku.dk by 19th September 2005. Submission of work submitted for formal publication elsewhere and work in progress is permitted. The abstracts of the accepted contributions will be available at the workshop. After the workshop, selected papers will be published in a special issue of "Nordic Journal of Computing". IMPORTANT DATES (TENTATIVE) 19 September: Submission of abstracts 5 October: Notification of acceptance 12 October: Registration (see below) 19-21 October: WORKSHOP REGISTRATION To register for the workshop, complete the registration form on the webpage of the workshop (www.diku.dk/NWPT05/) The workshop fee includes registration, participants proceedings, coffee, lunches, reception, and a banquet. PROGRAMME COMMITTEE o Neil D. Jones (chair), Univ. of Copenhagen, Denmark o Michael R. Hansen, Techn. U. of Denmark, Denmark o Magne Haveraaen, Univ. of Bergen, Norway o Hannu-Matti Jarvinen, Tampere Univ. of Tech., Finland o Kim G. Larsen, Aalborg Univ., Denmark o Bengt Nordstrom, Univ. of Gothen, Chalmers Univ. of Tech., Sweden o Olaf Owe, University of Oslo, Norway o Kaisa Sere, Abo Akademi University, Finland o Tarmo Uustalu, Inst. of Cubernetics, Estonia o Juri Vain, Tallinn Technical University, Estonia o Wang Yi, Uppsala Univ., Sw ORGANIZING COMMITTEE o Karin Outzen (secretary) o Jesper Andersen (graduate student) o Andrzej Filinski o Jakob Grue Simonsen o Neil Jones More (and current) information can be found at the workshop homepage: http://www.diku.dk/NWPT05

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