December 2006 - Haskell

haskell.org memory upgrade
by Paul Hudak 14 Dec '06

14 Dec '06

Dear Haskellers -- Haskell.org will go down today at 1500 EST for about 10 minutes for a memory upgrade. Sorry for the inconvenience, -Paul Hudak

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PLAN-X 2007: Call for Participation [and Program Updates]
by Torsten Grust 14 Dec '06

14 Dec '06

Call for Participation P L A N - X 2 0 0 7 Programming Language Technologies for XML An ACM SIGPLAN Workshop collocated with POPL 2007 Nice, France -- January 20, 2007 www.plan-x-2007.org || UPDATE: - Christoph Koch (U Saarland, Germany) will give the || || PLAN-X 2007 keynote speech. || || - The detailed program is available (included below). || Please join us for PLAN-X 2007, the fifth workshop in the PLAN-X series, dedicated to the interaction and integration of programming language technology and the world of XML. The XML data model and its associated languages add interesting twists to programming language practice as well as theory. Just like its four predecessors, the PLAN-X 2007 workshop turns the spotlight on how programming language technology can embrace and explain streaming XML transformations, types for XPath and XML updates, web service contracts, tree patterns in XQuery, LINQ and XML Schema, and more. PLAN-X 2007 will feature eight talks, three system demonstrations, extensive opportunity for discussion, and a keynote address (speaker to be announced). PLAN-X 2007 will be held in the Plaza Hotel (Nice, France) all-day on Saturday, January 20, 2007, just after and collocated with POPL 2007, the ACM SIGPLAN - SIGACT Symposium on Principles of Programming Languages (January 17-19, 2007). -- PROGRAM (Saturday, January 20, 2007) 09:00--10:00 Welcome Invited Talk by Christoph Koch (U Saarland, Germany) (title to be announced) 10:00--10:30 Coffee break 10:30--12:00 Session 1: Research Papers Streaming XML Transformations Using Term Rewriting (Alain Frisch, Keisuke Nakano) How to Recognise Different Kinds of Tree Patterns From Quite a Long Way Away (Jan Hidders, Philippe Michiels, Jerome Simeon, Roel Vercammen) Lux: A Lightweight, Statically Typed XML Update Language (James Cheney) 12:00--01:30 Workshop lunch (provided) 01:30--03:10 Session 2: Research Papers and Demo Presentations A Theory of Contracts for Web Services (Giuseppe Castagna, Nils Gesbert, Luca Padovani) XML Transformation Language Based on Monadic Second Order Logic (Kazuhiro Inaba, Haruo Hosoya) Demo: MTran: An XML Transformation Language Bases on Monadic Second Order Logic (Kazuhiro Inaba, Haruo Hosoya) Demo: XCentric: A Logic-Programming Language for XML Processing (Jorge Coelho, Mário Florido) Demo: LINQ to XSD (Ralf Lämmel) Demo: GeLaBa: A Framework to Define Classes of XML Documents and to Automatically Derive Specialized Infrastructures (Benoit Pin, Georges André Silber) 03:10--04:00 Interactive Demos and Coffee break 04:00--05:30 Session 3: Research Papers XPath Typing Using a Modal Logic with Converse for Finite Trees (Pierre Geneves, Nabil Layaida, Alan Schmitt) Deciding Equivalence of Top-Down XML Transformations in Polynomial Time (Sebastian Maneth, Helmut Seidl) A Logic Your Typechecker Can Count On: Unordered Tree Types in Practice (Nate Foster, Benjamin C. Pierce, Alan Schmitt) -- REGISTRATION PLAN-X 2007 is held in cooperation with POPL 2007. You can register for the workshop via the POPL 2007 registration process (online or offline). Please visit http://www.regmaster.com/conf/popl2007.html Registration rates are shown below. The rates are unaffected by the POPL 2007 early bird registration deadline. Note that you can upgrade an existing POPL 2007 registration to include PLAN-X 2007. Workshop-only registration is possible as well. ACM or SIGPLAN Member $89 Non-Member $99 Student $89 Your registration includes a copy of the PLAN-X 2007 informal proceedings, coffee breaks, and lunch. -- PLAN-X 2007 Workshop Chairs - General Chair - Program Chair Torsten Grust Giorgio Ghelli TU München U Pisa Munich, Germany Pisa, Italy grust(a)in.tum.de ghelli(a)di.unipi.it -- PLAN-X 2007 Program Committee - Michael Benedikt (Lucent, USA) - Daniela Florescu (Oracle, USA) - Alain Frisch (INRIA Roquencourt, France) - Giorgio Ghelli, Chair (U Pisa, Italy) - Haruo Hosoya (U Tokyo, Japan) - Anders Møller (U Aarhus, Denmark) - Mukund Raghavachari (IBM T.J. Watson Research Center, USA) - Alan Schmitt (INRIA Rhône-Alpes, France) - Sophie Tison (U Lille, France) - Philip Wadler (U Edinburgh, UK)

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TLDI'07: Last Call for Participation
by Francois Pottier 14 Dec '06

14 Dec '06

****************************************************************************** The 2007 ACM SIGPLAN Workshop on Types in Language Design and Implementation (TLDI'07) Affiliated with the 34th ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL'07) Call for Participation http://www.cs.berkeley.edu/~necula/tldi07/ ****************************************************************************** Preliminary programme Invited talks: Kathleen Fisher (AT&T Research) Conor McBride (University of Nottingham) Accepted papers: A Garbage-Collecting Typed Assembly Language Chris Hawblitzel, Heng Huang, Lea Wittie and Juan Chen A graphical presentation of MLF types with a linear-time unification algorithm Didier Rémy and Boris Yakobowski An Open Framework for Foundational Proof-Carrying Code Xinyu Feng, Zhaozhong Ni, Zhong Shao and Yu Guo Modular Information Hiding and Type-Safe Linking for C Saurabh Srivastava, Michael Hicks and Jeffrey Foster Semantics of an Effect Analysis for Exceptions Nick Benton and Peter Buchlovsky System F with Type Equality Coercions Martin Sulzmann, Manuel Chakravarty, Simon Peyton Jones and Kevin Donnelly ****************************************************************************** Scope The role of types and proofs in all aspects of language design, compiler construction, and software development has expanded greatly in recent years. Type systems, type analyses, and formal deduction have led to new concepts in compilation techniques for modern programming languages, verification of safety and security properties of programs, program transformation and optimization, and many other areas. In light of this expanding role of types, the ACM SIGPLAN Workshop on Types in Language Design and Implementation (TLDI'07) follows five previous International Workshops on types in compilation and language design (TIC'97, TIC'98, TIC'00, and TLDI'03 and TLDI'05), with the hope of bringing together researchers to share new ideas and results in this area. ****************************************************************************** General Chair François Pottier INRIA Rocquencourt BP 105 78153 Le Chesnay Cedex FRANCE francois.pottier(a)inria.fr Program Chair George Necula University of California 783 Soda Hall Berkeley, CA 94720 necula(a)cs.berkeley.edu Program Committee Damien Doligez, INRIA Peter Lee, Carnegie Mellon University Andrew Kennedy, Microsoft Research, Cambridge Naoki Kobayashi, Tohoku University George Necula (chair), University of California, Berkeley Randy Pollack, Edinburgh University Norman Ramsey, Harvard University David Tarditi, Microsoft Research, Redmond Stephanie Weirich, University of Pennsylvania Hongwei Xi, Boston University

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interpreter ouput in color
by Walter Moreira 14 Dec '06

14 Dec '06

Hi all. I was wondering if some people miss the colored output of some applications, such like the IPython enhanced shell. I've been googling for similar options for Haskell but I found nothing. I feel that the type error messages, for example, would be a lot more readable (or at least quicker to read). Is there a way to write plugins for ghci to get this?, or do you people have some suggestion about what would be the easiest component to hack for applying colors? Thank you. Cheers, Walter

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Re: [Haskell] ANNOUNCE: Phooey -- a Functional UI library for Haskell
by Conal Elliott 13 Dec '06

13 Dec '06

Hi Neil, Thanks for the pointer. From first skim-through at some PropLang library & example code, I'm not seeing much similarity between the two systems. GuiHaskell looks nifty. Cheers, - Conal On 12/13/06, Neil Mitchell <ndmitchell(a)gmail.com> wrote: > > Hi, > > > Thanks for your comments, Steve. They're getting me closer to a clear > > explanation, which will be helpful in the paper I'm writing. > > I was going to polish up PropLang before releasing it, but if you're > writing a paper, and I go and release PropLang just after you've put > the finishing touches on it, you'll hunt me down and kill me :) > > As such, here is an announcement that PropLang exists, and is cool. > > See the darcs repo: http://www.cs.york.ac.uk/fp/darcs/proplang/ - and > hopefully see some documentation in the future :) > > No arrows, but seems to have the same underlying idea. > > The darcs repo has a text editor (it had another sample, I'm sure, but > I can't see it!) > > Some selected hilights: > > -- CREATE VARIABLES > > -- is a document open > document <- newVar False > > -- is a document modified > modified <- newVar False > > -- the filename of the document, if its been saved > filename <- newVar Nothing > > -- SET UP RELATIONS BETWEEN PROPERTIES > txt!enabled =<= document > new!enabled =< with1 document not > saveas!enabled =< with2 document modified (&&) > --save!enabled =< with2 document modified (&&) > save!enabled =< (&&) =$$= document =$= modified > close!enabled =<= document > revert!enabled =<= modified > > -- SUPPORTS EVENTS TOO > new!onClicked += newDocument gui > save!onClicked += saveDocument gui > saveas!onClicked += saveAsDocument gui > close!onClicked += closeDocument gui > open!onClicked += openDocument gui > > -- COOL AND SIMPLE UNDO > revert!onClicked += (txt!text -<- lasttxt) > > modified =< with2 (txt!text) (lasttxt) (/=) > > let titleformat d m f = "TextEditor" ++ > (if d then " - " ++ maybe "<untitled>" id > f else "") ++ > (if m then " *" else "") > > -- REALLY COOL SETTING OF THE TITLE AUTOMATICALLY > window!text =< titleformat =$$= document =$= modified =$= filename > > -- CREATE A STATUS BAR WITH THE WORD COUNT IN ONE LINE! > sb!text =< (\x -> "Word count: " ++ show (length $ words x)) =$$= > txt!text > > I'll write up a tutorial or something at some point. > > It's written using Gtk2Hs, and works fine on both Linux and Windows. > GuiHaskell is written using this: > http://www-users.cs.york.ac.uk/~ndm/projects/guihaskell.php > > Thanks > > Neil >

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Waiting on multiple Chan-nels
by Setzer, Sebastian (ext) 12 Dec '06

12 Dec '06

Hi, How do you wait on multiple channels, but read only from one of them (the first that gets an entry)? Is there a library-function I missed which already does this? What do you think of this solution? Sebastian Setzer -------------------------------------------------------------- -- ghc chantest.hs -o chantest -- Usage: Enter "1", "2" or "0" to exit. import System.IO import Control.Concurrent import Control.Concurrent.Chan main :: IO() main = do chan1 <- newChan chan2 <- newChan c1Thread <- forkIO (printChan "c1" chan1) c2Thread <- forkIO (printChan "c2" chan2) c12Thread <- forkIO (printChannels "c12" [chan1, chan2]) mainloop chan1 chan2 mainloop :: Chan String -> Chan String -> IO () mainloop chan1 chan2 = do c <- getChar command c where -- chan1 and chan2 are in scope, here. go_on :: IO() go_on = mainloop chan1 chan2 command :: Char -> IO() command '0' = do print "done" command '1' = do writeChan chan1 "main: 1" go_on command '2' = do writeChan chan2 "main: 2" go_on command '\n' = do -- ignore go_on command c = do print ("illegal: " ++ [c]) go_on -- return microseconds seconds :: Int -> Int seconds = (* 1000000) printChan :: String -> (Chan String) -> IO() printChan name chan = do -- threadDelay (seconds 3) -- print (name ++ " ready") s <- readChan chan printString name s printChan name chan printChannels :: String -> [Chan String] -> IO() printChannels name channels = do -- select (zip channels (repeat (printString name))) select $ zip channels $ repeat $ printString name printChannels name channels printString :: String -> String -> IO () printString name s = print (name ++ ": " ++ s) select :: [(Chan a, a -> IO())] -> IO () select channel_handler_pairs = do threadDelay (seconds 3) print "TODO: implement select" {- TODO: implement select. - create MVar - For each element of the channel_handler_pairs - list, fork a thread. - wait on an MVar for the signal "I'm done" - kill all helper threads (just to free the resources. They wouldn't do any harm) In the helper-threads: - readChan - try to signal "I'm ready" on the MVar. If another thread was faster, unGetChan and exit - call the handler - signal "I'm done" and exit Problems: - If the Thread gets killed between readChan and unGetChan, the message is lost. - if another thread reads between readChan and unGetChan, its no fifo anymore (unlikely, because why would you want to read with multiple threads on the same Chan? - You'd use dupChan for that purpose. Unless you want every "event" to be handled only once. But then you would'nt use multiple threads, would you?) - "a" must be the same for every channel-handler-pair Thats easy: instead of channel-handler-tuples, put functions MVar -> IO() into the list and provide a nice-looking operator to create them - Probably inefficient (lots of helper threads) -}

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Reading from two fifos
by Setzer, Sebastian (ext) 12 Dec '06

12 Dec '06

Hi, Why doesn't this program start reading from one fifo until the second fifo gets opened (with cat), too? (It doesn't matter which fifo is opened first.) Why doesn't it print "forked" before "fifo1" is opened? After both fifos are open, it works as expected. I have ghc 6.6-3 on debian-linux (testing) Sebastian Setzer ------------------------------------------------------------------ -- Compile: ghc twofifo.hs -o twofifo -threaded -package unix-1.0 -- Usage: -- mkfifo fifo1 -- mkfifo fifo1 -- ./twofifo -- in two separate xterms: -- cat > fifo1 -- ... -- cat > fifo2 -- ... import System.IO import System.Posix.IO import System.Posix.Types import Control.Concurrent main :: IO() main = do f1Thread <- forkOS (openAndShowFile "fifo1") print "forked" hFlush stdout openAndShowFile "fifo2" openAndShowFile :: String -> IO() openAndShowFile name = do fd <- openFd name ReadOnly Nothing defaultFileFlags showFile name fd showFile :: String -> Fd -> IO() showFile name fd = do threadWaitRead fd (s, count) <- fdRead fd 1024 print (name ++ ": " ++ s) hFlush stdout showFile name fd

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The Monad.Reader call for copy
by Wouter Swierstra 12 Dec '06

12 Dec '06

It's still not too late to write something for the next issue of The Monad.Reader! We have a nice issue slowly shaping up, but your contribution is still very welcome. * The Monad.Reader * There are a large number of conferences and journals that accept research papers related to Haskell; unfortunately, the platform for non-academic publications is far less developed. This is where The Monad.Reader fits in. I believe that there are lots of people on these mailing lists that have plenty of ideas that might not be suitable for the the Haskell Workshop, for instance, but are nonetheless worth writing about. Sometimes such ideas end up as posts on a Haskell mailing list; sometimes they get posted on personal blogs; sometimes they disappear altogether. A lot of e-mails to these mailing lists deserve a more lasting place. * Submission Details * Get in touch with me if you intend to submit something -- the sooner you let me know what you're up to, the better. Please submit articles for the next issue by e-mail (wss at cs.nott.ac.uk) to me before **January 19th, 2007** . Articles should be written according to the guidelines available from http://www.haskell.org/haskellwiki/TheMonadReader Please submit your article PDF format. If you would like to submit an article, but have trouble with LaTeX please let me know and we'll sort something out. After a bit of deliberation, I decided it may be best to ask authors to make their source .tex source files available under a BSD license. This seems to "play nice" with other licenses; the originally proposed Creative Commons license caused some trouble. All the best, Wouter This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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Haskell Weekly News: December 12, 2006
by dons＠cse.unsw.edu.au 12 Dec '06

12 Dec '06

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/ Issue 53 - December 12, 2006 --------------------------------------------------------------------------- Welcome to issue 53 of HWN, a weekly newsletter covering developments in the Haskell community. Lots of new, practical Haskell libraries released this week, including support for ogg sound file parsing, a new user interface library, ftp clients and servers, database bindings as well as config files and logging. Announcements Visual Haskell 0.2. Krasimir Angelov [1]announced the final version of [2]Visual Haskell 0.2 is available! This is the first version that is: available for both VStudio 2003 and VStudio 2005; distributed with a stable GHC version (6.6). Additionally the plugin itself is much more stable than its first 0.0 version. 1. http://article.gmane.org/gmane.comp.lang.haskell.general/14608 2. http://www.haskell.org/visualhaskell Phooey: functional user interfaces for Haskell. Conal Elliott [3]announced Phooey, [4]a functional UI library for Haskell. GUIs are usually programmed in an 'unnatural' style, in that implementation dependencies are inverted, relative to logical dependencies. This reversal results directly from the imperative orientation of most GUI libraries. While outputs depend on inputs from a user and semantic point of view, the imperative approach imposes an implementation dependence of inputs on outputs. Phooey ('Phunctional ooser ynterfaces') retains the functional style, in which outputs are expressed in terms of inputs. In addition, Phooey supports dynamic input bounds, flexible layout, and mutually-referential widgets. It is [5]available via darcs. 3. http://article.gmane.org/gmane.comp.lang.haskell.general/14635 4. http://darcs.haskell.org/packages/phooey/doc 5. http://darcs.haskell.org/packages/phooey HOgg 0.2.0. Conrad Parker [6]announced HOgg 0.2.0. The [7]HOgg package provides a commandline tool for manipulating Ogg files, and a corresponding Haskell library. This is the initial public release. The focus is on correctness of Ogg parsing and production. The capabilities of the hogg commandline tool are roughly on par with those of the [8]oggz* tools, although hogg does not yet provide an equivalent to oggz-validate. HOgg supports chained and multiplexed Ogg bitstreams conformant with [9]RFC3533. HOgg can parse headers for CMML, FLAC, OggPCM, Speex, Theora and Vorbis media codecs, and can read and write Ogg Skeleton bitstreams. 6. http://article.gmane.org/gmane.comp.lang.haskell.cafe/17102 7. http://snapper.kfish.org/~conrad/software/hogg/ 8. http://www.annodex.net/software/liboggz/index.html 9. http://www.ietf.org/rfc/rfc3533.txt 10. http://article.gmane.org/gmane.comp.lang.haskell.general/14610 ftphs. John Goerzen [10]announced ftphs, [11]an FTP client and server library for Haskell. Its features include: easy to use operation; full support of text and binary transfers; optional lazy interaction; server can serve up a real or a virtual filesystem tree; Standards compliant. ftphs was previously a part of the MissingH library. The code in this release is unchanged from its state in MissingH, other than the changes necessary to make it a standalone package. 11. http://software.complete.org/ftphs AnyDBM 1.0.0. John Goerzen [12]announced AnyDBM, a generic DBM-type interface. [13]AnyDBM provides a generic infrastructure for supporting storage of hash-like items with String-to-String mappings. It can be used for in-memory or on-disk storage. Two simple backend drivers are included with this package: one that is RAM-only, and one that is persistent and disk-backed. The hdbc-anydbm package provides another driver, which lets you use simple tables in any SQL database to provide a DBM-like interface. MissingPy also provides a Python driver which lets you use any Python anydbm driver under Haskell AnyDBM. 12. http://article.gmane.org/gmane.comp.lang.haskell.general/14613 13. http://software.complete.org/anydbm ConfigFile 1.0.0. John Goerzen [14]announced ConfigFile, a parser and writer for handling sectioned config files in Haskell. The [15]ConfigFile module works with configuration files in a standard format that is easy for the user to edit, easy for the programmer to work with, yet remains powerful and flexible. It is inspired by, and compatible with, Python's ConfigParser module. It uses files that resemble Windows .INI-style files, but with numerous improvements. 14. http://article.gmane.org/gmane.comp.lang.haskell.general/14612 15. http://software.complete.org/configfile hslogger. John Goerzen [16]announced hslogger, a logging framework for Haskell. [17]hslogger's features include: each log message has a priority and a source associated with it; multiple log writers can be on the system; configurable global actions based on priority and source; extensible log writers (handlers); default handlers that write to the console, file handles, or syslog; easy to use operation. hslogger is the first package to be split off from the MissingH source. 16. http://article.gmane.org/gmane.comp.lang.haskell.general/14611 17. http://software.complete.org/hslogger MissingH 0.18.0. John Goerzen [18]announced MissingH 0.18.0. [19]MissingH is a large collection of assorted utility libraries for Haskell. Its primary audience is Haskell programmers that want to get practical things done fast. This release implements the first part of the MissingH transition. The major changes are: most code from other sources that had been merged into MissingH has been split off; stable, mostly standalone components of MissingH have been split off: hslogger, ftphs, ConfigFile, AnyDBM, and all modules renamed to more closely follow current Haskell naming practices. 18. http://article.gmane.org/gmane.comp.lang.haskell.general/14614 19. http://software.complete.org/missingh ZMachine 0.0. Samuel Bronson [20]announced a (partial) Z-machine interpreter in Haskell. It uses gtk2hs for the interface, though other interfaces could be implemented without actually changing the interpreter proper. The Z-machine is a virtual machine that was developed by Joel Berez and Marc Blank in 1979 and used by Infocom for its text adventure games. 20. http://article.gmane.org/gmane.comp.lang.haskell.glasgow.user/11397 Halp: Haskell Logic Prover. Dan Mead [21]announced the release of Halp, the simple logic prover. Right now it only supports simple first order logic but predicates are on the way. Theres also a simple gui written in Java 5 which is in the [22]darcs repository. 21. http://article.gmane.org/gmane.comp.lang.haskell.cafe/17104/ 22. http://taz.cs.wcupa.edu/~dmead/code/halp/ DList 0.1. Don Stewart [23]announced dlist 0.1, a library for difference lists in Haskell. Difference lists are a Haskell idiom for implementing O(1) append on lists, using functions to represent the lists. 23. http://article.gmane.org/gmane.comp.lang.haskell.general/14623 Haskell' This section covers the [24]Haskell' standardisation process. * [25]Infix multiparameter type classes * [26]Type sections * [27]Are pattern guards obsolete? 24. http://hackage.haskell.org/trac/haskell-prime 25. http://thread.gmane.org/gmane.comp.lang.haskell.prime/1948/focus=1948 26. http://thread.gmane.org/gmane.comp.lang.haskell.prime/1955/focus=1955 27. http://thread.gmane.org/gmane.comp.lang.haskell.prime/1956/focus=1956 Discussion Ninety Nine Haskell Problems. Andrew Wagner [28]mentioned that 99 Lisp exercises have been [29]ported to Haskell. Solving these exercises is a great way for relatively new haskell programmers to contribute something, since most of the problems are relatively simple. So have at them! All you need to do is write a canonical Haskell solution, and add it to the wiki. Please follow the instructions for 'reserving' a problem so we're not all duplicating each others' work. We should be able to knock these problems out in a matter of hours! 28. http://article.gmane.org/gmane.comp.lang.haskell.cafe/17324 29. http://haskell.org/haskellwiki/99_Haskell_exercises MissingH status. John Goerzen [30]announced that MissingH now has [31]a new Trac-based homepage, complete with wiki, Darcs repository information, source browser, bug tracker, and the various pieces of MissingH have been split off already into separate packages. The full list of changes is [32]available. 30. http://article.gmane.org/gmane.comp.lang.haskell.cafe/17156 31. http://software.complete.org/missingh 32. http://software.complete.org/missingh/wiki/TransitionPlanning Reversing a string of words: C# v Perl v Ruby v Haskell. Andrew Savige [33]invoked the Haskell cafe magicians with a comparison of string processing support across languages. 33. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/17197/focus=17197 Unlifted type variables in GHC. Brian Alliet [34]asked about the intricacies of supporting type variables with an unlifted kind. 34. http://thread.gmane.org/gmane.comp.lang.haskell.glasgow.user/11397/focus=11… Wanted: libraries. Don Stewart [35]asked for information about missing or substandard libraries to be documented on the wiki. 35. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/17222/focus=17222 Haskell for Dummies. Kirsten Chevalier [36]launched an interesting discussion to produce a new 'Practical Haskell' or 'Haskell for Dummies' textbook. 36. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/17240/focus=17240 Stratified monads. Mark Carroll [37]asked about experience with Espinosa's stratified monads in Haskell. 37. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/17266/focus=17266 Conference roundup hal: Haskell in Leipzig. [38]More than 25 Haskellers from all over Germany gathered in Leipzig for the first HaL, Haskell in Leipzig, meeting. The range of different backgrounds was broad and spanned both the academic and the business worlds, encompassing seasoned Haskell programmers as well as beginners. There were five talks and two discussion sessions, and a functional breakfast. One of the discussion sessions had IDE support (in particular, in Eclipse) as its topic, the other focused on the possibilities for promoting Haskell in the software industry. The talk topics ranged from the use of Haskell in web technology and in climate research, to specifics of programming (MonadFix, coding guidelines). A very Haskell-like language (CAL Quark) that offers access to Java libraries and can be compiled to JVM bytecode was also introduced. A second 'Haskell in Leipzig' meeting is planned for early spring 2007. [39]Summaries of the talks are available. 38. http://iba-cg.de/haskell.html 39. http://iba-cg.de/haskell.html The Haskell Hackathon. The Hac organisers [40]announced that extended registration for Hac 07, the Haskell libraries and infrastructure hackathon is open, via the [41]Hac website. 40. http://article.gmane.org/gmane.comp.lang.haskell.cafe/17132 41. http://haskell.org/haskellwiki/Hac_20007 Blog noise [42]Haskell news from the blogosphere. * [43]A Tree Grows Up in Haskell: Building a Dictionary Type * [44]Functional programming is a silver bullet * [45]Silver Bullets Incoming! * [46]The Division Bell Tolls for Me, Part One * [47]The Division Bell Tolls for Me, Part Two * [48]The Division Bell Tolls for Me, Part Three * [49]The Division Bell Tolls for Me, Part Four (Conclusion) * [50]The Divisive Aftermath * [51]Non-standard analysis, automatic differentiation, Haskell, and other stories * [52]Adventures in Haskell: parsing the game world * [53]Generalised Haskell * [54]Haskell tool tips * [55]Reconsidering my approach to learning Haskell * [56]A Sermon on Programming Languages * [57]Polyglot Programming * [58]Fibonacci series one-liner in Haskell * [59]An infinite list in Java * [60]The beauty of Haskell * [61]On Unit Testing and Type Safety * [62]Rewriting PLEAC Haskell? * [63]A newbie in Haskell land : The (->) monad * [64]Quick interpreters with the Reader monad * [65]bhc: Basic Haskell Compiler * [66]The lambda revolution: how you can help 42. http://planet.haskell.org/ 43. http://scienceblogs.com/goodmath/2006/12/a_tree_grows_up_in_haskell_bui_1.p… 44. http://cogito.blogthing.com/2006/12/06/no-silver-bullet-and-functional-prog… 45. http://cogito.blogthing.com/2006/12/08/silverbulletsincoming/ 46. http://praisecurseandrecurse.blogspot.com/2006/12/division-bell-tolls-for-m… 47. http://praisecurseandrecurse.blogspot.com/2006/12/division-bell-tolls-for-m… 48. http://praisecurseandrecurse.blogspot.com/2006/12/division-bell-tolls-for-m… 49. http://praisecurseandrecurse.blogspot.com/2006/12/division-bell-tolls-for-m… 50. http://praisecurseandrecurse.blogspot.com/2006/12/divisive-aftermath.html 51. http://vandreev.wordpress.com/2006/12/04/non-standard-analysis-and-automati… 52. http://jpmoresmau.blogspot.com/2006/12/adventures-in-haskell-parsing-game.h… 53. http://neilmitchell.blogspot.com/2006/12/generalised-haskell.html 54. http://monad.carnalreason.org/wordpress/?p=21 55. http://monad.carnalreason.org/wordpress/?p=20 56. http://www.dailyspeculations.com/ 57. http://memeagora.blogspot.com/2006/12/polyglot-programming.html 58. http://gimbo.org.uk/archives/2006/12/#001887 59. http://jpmoresmau.blogspot.com/2006/12/in-haskell-you-can-define-infinite.h… 60. http://clemens.endorphin.org/weblog/archives/2006-06.shtml#e2006-06-23T09_1… 61. http://blogs.teamb.com/craigstuntz/archive/2006/12/08/UnitTestingAndTypeSaf… 62. http://koweycode.blogspot.com/2006/12/rewriting-pleac-haskell.html 63. http://www.alpheccar.org/en/posts/show/61 64. http://cgi.cse.unsw.edu.au/~dons/blog/2006/12/11#interpreters-with-reader-m… 65. http://neilmitchell.blogspot.com/2006/12/bhc-basic-haskell-compiler.html 66. http://www.cse.unsw.edu.au/~dons/blog/2006/12/11#release-a-library-today Quotes of the Week * Jim Apple: The Haskell list probably has the widest 'knowledge bandwidth' of any mailing list I've ever seen, from total beginner questions to highly abstruse stuff which probably represents the cutting edge of PhD research. All are answered with detail and good humour. * [Seen on the Haskell mailing list]: Wow! I found your help terrific! Thank you! Can I give you some money? * Paul Johnson: Is functional programming an actual bona-fide silver bullet as defined by Brooks? I believe it is. Functional programming is based on a sound theory of scalable software engineering, and the empirical evidence clearly and consistently supports the theory. * Clemens Fruhwirth: After all the elegance I have to conclude that Haskell definitely deserves to be looked at. * sorear: Haskell is amazing. I'm still working on my infinite-types unifier, and in a day I've added sums, products, and lambda abstractions, refactored the code until there was a net *decrease* in LOC, and helped man #haskell all at the same time. This'd take me a week in C, no doubt. * Claus Reinke: The aim of update programming is to transform a store whose contents describe a problem into a store whose contents describe a solution. The aim of functional programming is to transform a program which describes a problem into a program which describes a solution. * Daveman: What if I don't want to obey the laws? Do they throw me in jail with the other bad monads? * Stinger: Sometimes Haskell seems like an arms race between weird mathematical constructs and my brain * astrolabe: Below a certain level of competence, coding is a destructive act. Like playing the violin. * dons: Gimme some lambda warez! * wy: [wy] lennart: Wow. You won the IOCCC three times! [augustss] I'm bad at C programming ;) * shapr: I think the Haskell approach works fine. That is, stick with research and do the best you can. Then after fifteen years of gestation, take over the world. * edwinb: Where does 'Oleg cornered me in a pub and explained delimited continuations to me' fit in? * emu: Design patterns are what you choose for wallpaper and carpets * kyevan: My skull is already mostly duct tape. And I'm only on page 25 of YAHT! * shapr: There's an important niche market for OSes that don't crash. Code Watch Tue Dec 5 23:18:45 PST 2006. Simon Peyton Jones. [67]Improve dependency analysis makes more dictionaries inlinable. 67. http://article.gmane.org/gmane.comp.lang.haskell.cvs.ghc/18123 Sat Dec 9 09:42:03 PST 2006. Ian Lynagh. [68]Add PowerPC to the list of SMP arches 68. http://article.gmane.org/gmane.comp.lang.haskell.cvs.ghc/18173 Mon Dec 11 14:25:34 PST 2006. Wolfgang Thaller. [69]Support MO_WriteBarrier in PowerPC NCG (lwsync instruction). 69. http://article.gmane.org/gmane.comp.lang.haskell.cvs.ghc/18217 About the Haskell Weekly News Each week, new editions are posted to [70]the Haskell mailing list as well as to [71]the Haskell Sequence and [72]Planet Haskell. [73]RSS is also available, and headlines appear on [74]haskell.org. Headlines are available as [75]PDF. The Haskell Weekly News is also [76]available in Spanish translation. To help create new editions of this newsletter, please see the [77]contributing information. Send stories to dons at cse.unsw.edu.au. The darcs repository is available at darcs get [78]http://www.cse.unsw.edu.au/~dons/code/hwn 70. http://www.haskell.org/mailman/listinfo/haskell 71. http://sequence.complete.org/ 72. http://planet.haskell.org/ 73. http://sequence.complete.org/node/feed 74. http://haskell.org/ 75. http://www.cse.unsw.edu.au/~dons/code/hwn/archives/20061212.pdf 76. http://haskell.org/haskellwiki/HWN/es 77. http://haskell.org/haskellwiki/HWN 78. http://www.cse.unsw.edu.au/~dons/code/hwn

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[newbie]any nice code to read?
by 云杨 12 Dec '06

12 Dec '06

hello,all, I am new to haskell,and have read some tutorial, but I would like to read some "real" code from "real" haskell project, I believe this will help me study and use haskell quickly. would anyone please give me some suggestion about opensource project that a new haskell user should study? thanks you.

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