December 2006 - Haskell

ANNOUNCE: dlist, difference lists supporting O(1) append
by dons＠cse.unsw.edu.au 12 Dec '06

12 Dec '06

This is DList, 0.1 I've cabalised, and packed up a small difference lists module. In case you've not used them, they are a Haskell idiom for implementing O(1) append and snoc, using functions to represent lists. I use them from time to time, and thought it a good idea to finally pack them into a library for all to share. Home: http://www.cse.unsw.edu.au/~dons/dlist.html Docs: http://www.cse.unsw.edu.au/~dons/dlist/Data-DList.html Source: http://www.cse.unsw.edu.au/~dons/code/dlist/ I've also described the entire process of releasing this library here: http://cgi.cse.unsw.edu.au/~dons/blog/2006/12/11#release-a-library-today Cheers, Don P.S. If you love Haskell, you'll write a library today!

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Call for papers -- FOAL: Foundations of Aspect-Oriented Languages 2007
by Ralf Lammel 11 Dec '06

11 Dec '06

[Added a subject. Please accept my apologies! Foundations of AOP and AO languages have benefitted from the functional programming community for a while now. Haskellers, please have a look. Thanks! Ralf] Call For Papers FOAL: Foundations of Aspect-Oriented Languages 2007 A one day workshop affiliated with AOSD 2007 in Vancouver, British Columbia. Submission Deadline: 23:00 GMT, 10 January 2007 Notification of Acceptance: 2 February 2007 Final Versions of Papers Due: 1 March 2007 Workshop: 13 March 2007 Themes and Goals FOAL is a forum for research in foundations of aspect-oriented programming languages. Areas of interest include but are not limited to: * Semantics of aspect-oriented languages * Specification and verification for such languages * Type systems * Static analysis * Theory of testing * Theory of aspect composition * Theory of aspect translation (compilation) and rewriting The workshop aims to foster work in foundations, including formal studies, promote the exchange of ideas, and encourage workers in the semantics and formal methods communities to do research in the area of aspect-oriented programming languages. All theoretical and foundational studies of this topic are welcome. The goals of FOAL are to: * Make progress on the foundations of aspect-oriented programming languages. * Exchange ideas about semantics and formal methods for aspect-oriented programming languages. * Foster interest within the programming language theory and types communities in aspect-oriented programming languages. * Foster interest within the formal methods community in aspect-oriented programming and the problems of reasoning about aspect-oriented programs. Workshop Format The planned workshop format is primarily presentation of papers and group discussion. Talks will come in three categories: long (30 minutes plus 15 minutes of discussion), regular (20 minutes plus 5 minutes of discussion) and short (7 minutes plus 3 minutes of discussion). The short talks will allow for presentations of topics for which results are not yet available, perhaps for researchers who are seeking feedback on ideas or seek collaborations. We also plan to ensure sufficient time for discussion of each presentation by limiting the overall number of talks. Submissions Invitation to the workshop will be based on papers selected by the program committee; those wishing to attend but not having a paper to submit should contact the organizers directly to see if there is sufficient space in the workshop. FOAL solicits long, regular, and short papers on all areas of formal foundations of AOP languages. Submissions will be read by the program committee and designated reviewers. Papers will be selected for long, regular, and short presentation at the workshop based on their length, scientific merit, innovation, readability, and relevance. Papers previously published or already being reviewed by another conference are not eligible. Some papers may not be selected for presentation, and some may be selected for presentation in shorter talks than their paper length would otherwise command. We will limit the length of paper presentations and the number of papers presented to make sure that there is enough time for discussion. Papers presented at the workshop will be included in a technical report (from Iowa State University). Authors will retain their own copyright to the papers. Publication of papers at other venues will thus remain possible. We will also investigate having a special issue of a journal for revisions of selected papers after the workshop. Authors should note the following details: * Submissions are due no later than 23:00 GMT, 10 January 2007. (This is a firm deadline.) * Authors must indicate whether they wish to be considered for a long, regular, or short presentation. * Papers for long presentations must not exceed 10 pages in length; those for regular presentations must not exceed 7 pages in length, and those for short presentations must not exceed 3 pages in length. * Some papers may not be selected for presentation, and some may be selected for presentation in shorter talks than requested. * We encourage use of the ACM Conference format <http://www.acm.org/sigs/pubs/proceed/template.html> for submissions, as this will be required for accepted papers. You must add page numbers (which are not part of the standard format) to your submissions, to make adding comments easier. * Submissions are to be made to the following URL: http://continue.cs.brown.edu/servlets/foal07/continue.ss We will notify the corresponding author of papers that are selected for presentation at the workshop by 2 February 2006. Early registration for AOSD (you must register for AOSD to attend the workshop) is 9 February 2006. Final versions of papers for the proceedings will be due on 1 March 2006. Important Dates Submission Deadline: 23:00 GMT, 10 January 2007 Notification of Acceptance: 2 February 2007 Final Versions of Papers Due: 1 March 2007 Workshop: 13 March 2007 For more information, visit the FOAL Workshop home page (at http://www.cs.iastate.edu/FOAL)

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(no subject)
by Ralf Lammel 11 Dec '06

11 Dec '06

[Foundations of AOP and AO languages have benefitted from the functional programming community for a while now. Haskellers, please have a look. Thanks! Ralf] Call For Papers FOAL: Foundations of Aspect-Oriented Languages 2007 A one day workshop affiliated with AOSD 2007 in Vancouver, British Columbia. Submission Deadline: 23:00 GMT, 10 January 2007 Notification of Acceptance: 2 February 2007 Final Versions of Papers Due: 1 March 2007 Workshop: 13 March 2007 Themes and Goals FOAL is a forum for research in foundations of aspect-oriented programming languages. Areas of interest include but are not limited to: * Semantics of aspect-oriented languages * Specification and verification for such languages * Type systems * Static analysis * Theory of testing * Theory of aspect composition * Theory of aspect translation (compilation) and rewriting The workshop aims to foster work in foundations, including formal studies, promote the exchange of ideas, and encourage workers in the semantics and formal methods communities to do research in the area of aspect-oriented programming languages. All theoretical and foundational studies of this topic are welcome. The goals of FOAL are to: * Make progress on the foundations of aspect-oriented programming languages. * Exchange ideas about semantics and formal methods for aspect-oriented programming languages. * Foster interest within the programming language theory and types communities in aspect-oriented programming languages. * Foster interest within the formal methods community in aspect-oriented programming and the problems of reasoning about aspect-oriented programs. Workshop Format The planned workshop format is primarily presentation of papers and group discussion. Talks will come in three categories: long (30 minutes plus 15 minutes of discussion), regular (20 minutes plus 5 minutes of discussion) and short (7 minutes plus 3 minutes of discussion). The short talks will allow for presentations of topics for which results are not yet available, perhaps for researchers who are seeking feedback on ideas or seek collaborations. We also plan to ensure sufficient time for discussion of each presentation by limiting the overall number of talks. Submissions Invitation to the workshop will be based on papers selected by the program committee; those wishing to attend but not having a paper to submit should contact the organizers directly to see if there is sufficient space in the workshop. FOAL solicits long, regular, and short papers on all areas of formal foundations of AOP languages. Submissions will be read by the program committee and designated reviewers. Papers will be selected for long, regular, and short presentation at the workshop based on their length, scientific merit, innovation, readability, and relevance. Papers previously published or already being reviewed by another conference are not eligible. Some papers may not be selected for presentation, and some may be selected for presentation in shorter talks than their paper length would otherwise command. We will limit the length of paper presentations and the number of papers presented to make sure that there is enough time for discussion. Papers presented at the workshop will be included in a technical report (from Iowa State University). Authors will retain their own copyright to the papers. Publication of papers at other venues will thus remain possible. We will also investigate having a special issue of a journal for revisions of selected papers after the workshop. Authors should note the following details: * Submissions are due no later than 23:00 GMT, 10 January 2007. (This is a firm deadline.) * Authors must indicate whether they wish to be considered for a long, regular, or short presentation. * Papers for long presentations must not exceed 10 pages in length; those for regular presentations must not exceed 7 pages in length, and those for short presentations must not exceed 3 pages in length. * Some papers may not be selected for presentation, and some may be selected for presentation in shorter talks than requested. * We encourage use of the ACM Conference format <http://www.acm.org/sigs/pubs/proceed/template.html> for submissions, as this will be required for accepted papers. You must add page numbers (which are not part of the standard format) to your submissions, to make adding comments easier. * Submissions are to be made to the following URL: http://continue.cs.brown.edu/servlets/foal07/continue.ss We will notify the corresponding author of papers that are selected for presentation at the workshop by 2 February 2006. Early registration for AOSD (you must register for AOSD to attend the workshop) is 9 February 2006. Final versions of papers for the proceedings will be due on 1 March 2006. Important Dates Submission Deadline: 23:00 GMT, 10 January 2007 Notification of Acceptance: 2 February 2007 Final Versions of Papers Due: 1 March 2007 Workshop: 13 March 2007 For more information, visit the FOAL Workshop home page (at http://www.cs.iastate.edu/FOAL)

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Num is such a fat and greedy class
by Dan Weston 11 Dec '06

11 Dec '06

The following observations are not new, insightful, or gracious, but I was lusting after the innocent +,-,* operators for my own evil ends and was mildly curious why... Num is such a fat and greedy class. If you want to marry Cinderella, you have to take her ugly stepsisters too. 1) Groups may only want to define addition. Why can't they use + (instead of <+>, >++++?&**+>, or other such perversion)? 2) Affine spaces have a (-) but no (+). Worse, the signature might be (-) :: Point -> Point -> Vector, which doesn't unify with (a -> a -> a). Wouldn't the following be more useful/general? class Subtraction a b | a -> b where (-) :: a -> a -> b Or would this require needless type annotation for the common subset of (a -> a -> a) instances? 3) Quaternions have no signum, unit quaternions have (*), (/) but no (+) or (-), abs would have a different signatures (Quaternion -> Double) which doesn't unify with (a -> a), and fields cannot be scaled with (*) as in (*) :: (Field f) => Double -> f -> f Would it not make sense to put each of these operators (division too) into their own individual superclasses that Num inherits? My (obviously naive) philosophy about type classes is that operations should be bundled only when they are mutually recursive (i.e. there is more than one useful minimal definition). If there is just one minimal set of operations, they can be in their own parent class too. Then again, I should get over my lust and stick with my own operators <+++++++++>, <---------------------->, and <*******>. Not too pretty, but they have a wonderful personality all their own! Dan

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Re: [Haskell] ANNOUNCE: ZMachine 0.0
by Samuel Bronson 09 Dec '06

09 Dec '06

On 12/9/06, Neil Mitchell <ndmitchell(a)gmail.com> wrote: > Hi Samuel, > > For future releases can you put up a little description of what a Z > Machine is in the email? Hmm. That would probably be a good idea ;-). But I don't see why I can't do that now, too. Except I actually want to describe the Z-machine, because apparantly the Z machine is a big giant machine covered in what looks like lightning. Anyway, here is the description from Wikipedia: 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. Infocom compiled game code to files containing Z-machine instructions (called story files, or Z-code files), and could therefore port all its text adventures to a new platform simply by writing a Z-machine implementation for that platform. With the large number of incompatible home computer systems in use at the time, this was an important advantage over using native code (or developing some compiler for each system). And I'll also note that, since then, a lot of people have used Graham Nelson's Inform compiler to write their own "text adventure games" (or "interactive fiction", as they like to call it) for the Z-machine, many of which are available at the IF archive (ifarchive.org)

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ANNOUNCE: ZMachine 0.0
by Samuel Bronson 09 Dec '06

09 Dec '06

I've written a (partial) Z-machine interpreter in Haskell. It is missing lots of stuff, but I got it to the point where it doesn't cause actual pain to play with it ;-). It uses gtk2hs for the interface, though other interfaces could be implemented without actually changing the interpreter proper. (Though I suppose you'd want to get rid of all the trace output if you were going to write a curses UI.) You can either darcs get http://naesten.dyndns.org:8080/repos/ZMachine or grab a tarball at http://naesten.dyndns.org:8080/repos/ZMachine/ZMachine-0.0.tar.gz Patches and comments are greatly desired. (Except for "where is the status area". At least I don't have the stuff intended for the status area going to the main output area like it used to!)

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ANN: hpodder 0.99.1
by John Goerzen 08 Dec '06

08 Dec '06

Version 0.99.1 of hpodder is out. This version has been altered to be compatible with the new MissingH, ConfigFile, and hslogger packages. It also contains some minor bugfixes. hpodder has a new homepage: http://software.complete.org/hpodder

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ANN: MissingH 0.18.0
by John Goerzen 08 Dec '06

08 Dec '06

I'm pleased to announce release 0.18.0 of MissingH. This release implements the first part of the MissingH transition discussed on haskell-cafe. Detail on the planned changes can be found at http://software.complete.org/missingh/wiki/TransitionPlanning. Note that not all of those changes have been carried out with this release. 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. * All modules renamed to more closely follow current Haskell naming practices 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. It also serves as a staging area of sorts for useful, general-purpose Haskell code. This could be code that may eventually wind up in base Haskell libraries, or it could grow into a library in its own and be forked off. Or it could remain in MissingH indefinately. You can find the MissingH homepage, which features a wiki, downloads, API reference, darcs repository viewer, and bug tracker, at: http://software.complete.org/missingh -- John Goerzen Author, Foundations of Python Network Programming http://www.amazon.com/exec/obidos/tg/detail/-/1590593715

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ANN: hslogger 1.0.0
by John Goerzen 08 Dec '06

08 Dec '06

hslogger 1.0.0 has been released. hslogger is a logging framework for Haskell. Here are some of its features: * 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 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. You can find the hslogger homepage, which features a wiki, downloads, API reference, darcs repository viewer, and bug tracker, at: http://software.complete.org/hslogger

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ANN: ConfigFile 1.0.0
by John Goerzen 08 Dec '06

08 Dec '06

Hi, I'm pleased to announce version 1.0.0 of ConfigFile. ConfigFile is a parser and writer for handling sectioned config files in Haskell. The 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. ConfigFile provides simple calls to both read and write config files. It's possible to make a config file parsable by this module, the Unix shell, and make. ConfigFile was previously a part of the MissingH library where it was known as ConfigParser. The code in this release is unchanged from its state in MissingH, other than the changes necessary to make it a standalone package. You can find the ConfigFile homepage, which features a wiki, downloads, API reference, darcs repository viewer, and bug tracker, at: http://software.complete.org/configfile

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