[Haskell] Haskell Weekly News: November 22, 2006

Donald Bruce Stewart dons at cse.unsw.edu.au
Wed Nov 22 07:45:18 EST 2006

Haskell Weekly News
Issue 50 - November 22, 2006

   Welcome to issue 50 of HWN, a weekly newsletter covering developments
   in the Haskell community.

   This week a new release of the Haskell XML Toolbox, and details for
   the inaugural Haskell Hackathon are announced. And the HWN half
   century of issues is on the board!


     * Haskell XML Toolbox 7.0. Uwe Schmidt [1]released a new version of
       the [2]Haskell XML Toolbox. New in 7.0 is a module for XSLT
       transformation. The XSLT module implements most of the XSLT
       standard. The development of the XSLT module is done by Tim
       Walkenhost in his master thesis, describing the design of the
       transformer (and the limitations) is included in the distribution.
       HXT 7.0 works with ghc-6.4 and ghc-6.6. [3]A tutorial is available
       in the Haskell wiki.

   1. http://article.gmane.org/gmane.comp.lang.haskell.general/14487
   2. http://www.fh-wedel.de/~si/HXmlToolbox/index.html
   3. http://www.haskell.org/haskellwiki/HXT

     * Hac: Haskell Hackathon 2007. The Hac organisers [4]announced that
       the inaugural Haskell Hackathon, [5]Hac 2007, will be held at
       Oxford University Computing Laboratory, January 10-12, 2007. The
       plan is to hack on Haskell infrastructure, tools, libraries and
       compilers. To attend please register, and get ready to hack those

   4. http://article.gmane.org/gmane.comp.lang.haskell.general/14489
   5. http://haskell.org/haskellwiki/Hac_2007

     * System.FilePath 0.11. Neil Mitchell [6]announced the release of
       [7]System.FilePath 0.11, a library for manipulating FilePath's
       correctly on both Posix and Windows.

   6. http://article.gmane.org/gmane.comp.lang.haskell.general/14485
   7. http://www-users.cs.york.ac.uk/~ndm/projects/libraries.php#filepath

     * Darcs release candidate. Tommy Pettersson [8]announced it's time
       for a new darcs release candidate, 1.0.9rc2. There will probably
       be yet another release candidate (rc3) before final 1.0.9. Get

   8. http://article.gmane.org/gmane.comp.version-control.darcs.devel/5010

     * Safe library 0.1. Neil Mitchell [9]announced the release of
       [10]Safe library, 0.1. People often have a problem with pattern
       match errors, and the only helpful message they get is: 'pattern
       match error'. The Safe library hopes to eliminate some of the
       frustration this causes by providing versions of these partial
       functions with more helpful error messages.

   9. http://article.gmane.org/gmane.comp.lang.haskell.general/14475
  10. http://www-users.cs.york.ac.uk/~ndm/projects/libraries.php#safe

     * LocH, located errors 0.1. Don Stewart [11]announced the release of
       LocH, a small Haskell module providing source location-specific
       error messages and debugging strings for Haskell code. It uses the
       compiler-expanded 'assert' token, rather than cpp or m4, to
       provide a lightweight approach to generating source locations. No
       preprocessor is required. More information is available at [12]the
       LocH site, including [13]API documentation.

  11. http://article.gmane.org/gmane.comp.lang.haskell.general/14475
  12. http://www.cse.unsw.edu.au/~dons/loch.html
  13. http://www.cse.unsw.edu.au/~dons/loch/Debug-Trace-Location.html

     * Starting your own Haskell project. Jason Dagit and Don Stewart
       [14]expanded on the document describing how best to [15]set up a
       new Haskell project, leading to the creation of [16]mkcabal,a new
       tool for setting up cabalised Haskell projects.

  14. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16689/focus=16689
  15. http://haskell.org/haskellwiki/How_to_write_a_Haskell_program
  16. http://article.gmane.org/gmane.comp.lang.haskell.cabal.devel/269


   This section covers the [17]Haskell' standardisation process.

     * [18]Defaults
     * [19]Pattern guards and where clauses

  17. http://hackage.haskell.org/trac/haskell-prime
  18. http://thread.gmane.org/gmane.comp.lang.haskell.prime/1907/focus=1907
  19. http://thread.gmane.org/gmane.comp.lang.haskell.prime/1904/focus=1904


   This week's proposals and extensions to the [20]standard libraries.

     * [21]Add parsing (and some other changes) to the time package

  20. http://haskell.org/haskellwiki/Library_submissions
  21. http://article.gmane.org/gmane.comp.lang.haskell.libraries/5706


     * New Arrows tutorial. Tim Newsham [22]wrote a small arrows
       tutorial, and is looking for feedback.

  22. http://www.thenewsh.com/~newsham/x/arrow.txt

     * Yhc.Core backends for Haskell/Javascript/C. Neil Mitchell
       [23]asked about the direction the Yhc Core backends should take.

  23. http://article.gmane.org/gmane.comp.lang.haskell.yhc/460

     * The Burrows Wheeler Transformation. Jon Fairbairn [24]proposed a
       game to find the most elegant implementation of the Burrows
       Wheeler transformation and its inverse.

  24. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16650/focus=16650

     * More fusion. Claus Reinke [25]described a method for avoiding the
       O(n) overhead of cons in strict ByteStrings. Some alternative
       strategies were also suggested.

  25. http://thread.gmane.org/gmane.comp.lang.haskell.glasgow.user/11267/focus=11267

     * Extending TypeEq: topEq for types. Nicolas Frisby [26]described a
       solution to an interesting type problem using TypeEq, Oleg
       followed up with an alternate solution

  26. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16638/focus=16638

     * Debugging by the rules. Don Stewart [27]described an idea to use
       rewrite rules to change mysterious failing functions to more
       useful variants. More details on using rewrite rules for various
       ticks have been [28]collected on the wiki.

  27. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16577/focus=16577
  28. http://www.haskell.org/haskellwiki/Playing_by_the_rules

     * Generalising zip. Jason Dagit [29]wondered about a generalisation
       of zip to encode functions like isPrefixOf

  29. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16626/focus=16626

     * Heterogeneous collections. Valentin Gjorgjioski [30]asked about
       techniques for heterogeneous data in Haskell. Several solutions
       were suggested, and a [31]new wiki page collects the details.

  30. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/16653/focus=16653
  31. http://haskell.org/haskellwiki/Heterogenous_collections

Blog noise

   [32]Haskell news from the blogosphere.
     * [33]The Maybe type in Java
     * [34]Erlang User Conference
     * [35]The Missing LINQ
     * [36]APLAS 06
     * [37]The New Lambda Expressions Feature in C# 3.0
     * [38]Edit Graphs
     * [39]A search engine (core) written in Haskell
     * [40]Vim indentation mode for Haskell
     * [41]Haskell Transactional Cache
     * [42]Haskell support added to Google Code Search
     * [43]The type system of ECMA Eiffel (modelled in Haskell)
     * [44]Diff in Haskell
     * [45]Computers were invented to keep track of boring things
     * [46]Lazy lists as iterators
     * [47]Library use in the Common Lisp community
     * [48]Local and global side effects with monad transformers
     * [49]Eratosthenes sieve
     * [50]Lazy streams for Lua
     * [51]Language design
     * [52]Overlap function in Haskell for rectangles

  32. http://planet.haskell.org/
  33. http://blog.tmorris.net/maybe-in-java
  34. http://www.process-one.net/index.php/en/comments/erlang_user_conference_2006/
  35. http://eamon.nerbonne.org/2006/11/gwc-missing-linq.html
  36. http://blog.tmorris.net/aplas-06/
  37. http://www.developer.com/net/csharp/article.php/3598381
  38. http://alangloria.blogspot.com/2006/11/edit-graphs-im-currently-hacking.html
  39. http://haskell-web.blogspot.com/2006/11/search-engine-written-in-haskell.html
  40. http://koweycode.blogspot.com/2006/11/haskell-vim-indentation.html
  41. http://haskell-web.blogspot.com/2006/11/transactional-cache-for-haskell.html
  42. http://groups.google.com/group/Google-Code-Search/browse_thread/thread/a1f83fae9d771c29/8ad7cd89b262ee28#8ad7cd89b262ee28
  43. http://teameiffel.blogspot.com/2006/11/type-system-of-ecma-eiffel.html
  44. http://alangloria.blogspot.com/2006/11/okay.html
  45. http://dynamic.ropine.com/yesh/article/computers-were-invented-to-keep-track-of-boring-things
  46. http://community.livejournal.com/evan_tech/206250.html
  47. http://sigkill.dk/blog/archives/240-Library-use-in-the-Common-Lisp-community.html
  48. http://sigfpe.blogspot.com/2006/09/local-and-global-side-effects-with.html
  49. http://kenta.blogspot.com/2006/11/eratosthenes-sieve.html
  50. http://salimma.livejournal.com/72850.html
  51. http://jlouisramblings.blogspot.com/2006/11/on-language-design.html
  52. http://sancho-ex.livejournal.com/7056.html

Quotes of the Week

     * Larry Wall: People who succeed in brushing up on Haskell do so by
       brushing up lazily.

     * xerox: [dons] then again, bots themselves are simple. [xerox]
       '...they are just a morphism in the category of IRC channels
       together with an endomapping ...'

     * Dave Love: Presumably people with the taste to program in Haskell
       will use Emacs anyway.

     * Baughn: I know I always have trouble explaining what the weather
       is like without involving foldr somehow.

     * Korollary: Darcs is free of chemical toxins of big pharma. It's
       made using all natural herbs and other woo. It's good for you.

     * Pseudonym: A 'newbie', in Haskell, is someone who hasn't yet
       implemented a compiler. They've only written a monad tutorial.

     * astrolabe: I guess missile launching would have to be in IO

     * dons: Java's type system is unsuitable for young children, the
       elderly or infirm of constitution

     * earthy: The Haskell standard Prelude is ... a treasure trove. But
       it does require breaking your mind and reassembling the pieces to
       unlock the trove.

     * emu: Hijack the stack and take this compiler to Fun-land!

     * norpan: The comonad of the No monad is the Yes monad?

     * robreim: I'm in your base hacking all your lambdas

     * shapr: I was chatting with someone who writes Haskell and at some
       point they said they're not an academic, and I said that too. And
       then there was what I perceived to be a small disbelieving

     * simonpj: Maybe if I had an Oleg implant I could express all this
       in the type system

     * skew: [On the subject of strictness] There is a sequet

     * ski: Please talk to your son or daughter about parametric

     * wadler: The way we can tell it's C# instead of Haskell is because
       it's nine lines instead of two.

Code Watch

     * Wed Nov 8 09:14:52 PST 2006. Alexey Rodriguez. [53]Addition of
       PAPI to the RTS. [54]PAPI is a library that supports use of the
       performance counters built into most CPUs for measuring things
       like cache misses and branch mispredictions. Alexey Rodriguez has
       added support for PAPI to the RTS, so we can take measurements of
       any of the CPU performance counters during the run of a Haskell
       program, and we even separate out results for the GC from results
       for the mutator.

  53. http://article.gmane.org/gmane.comp.lang.haskell.cvs.ghc/17864
  54. http://icl.cs.utk.edu/papi/

About the Haskell Weekly News

   Each week, new editions are posted to [55]the Haskell mailing list as
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  55. http://www.haskell.org/mailman/listinfo/haskell
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  60. http://haskell.org/haskellwiki/HWN/es
  61. http://haskell.org/haskellwiki/HWN

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