[Haskell-cafe] Haskell Weekly News: Issue 103 - January 31, 2009

Brent Yorgey byorgey at seas.upenn.edu
Sat Jan 31 10:04:00 EST 2009

Haskell Weekly News
Issue 103 - January 31, 2009

   Welcome to issue 103 of HWN, a newsletter covering developments in the
   [1]Haskell community.


   HDBC v2.0 now available. John Goerzen [2]announced that [3]HDBC v2.0 is
   now available. Simultaneously, [4]HDBC-sqlite3, [5]HDBC-postgresql, and
   [6]HDBC-odbc v2.0 have also been uploaded to Hackage. A guide to new
   features and migration can be [7]found here.

   Extensible and Modular Generics for the Masses: emgm-0.2. Sean Leather
   [8]announced the second major release of [9]Extensible and Modular
   Generics for the Masses (EMGM), a library for generic programming in
   Haskell using type classes and a sum-of-products view. Improvements
   over emgm-0.1 include type representation derivation using Template
   Haskell, documentation improvements, a bimap function, and more.

   incremental-sat-solver. Sebastian Fischer [10]announced the
   [11]incremental-sat-solver library, which provides an implementation of
   the [12]Davis-Putnam-Logemann-Loveland algorithm for the Boolean
   satisfiability problem. It not only allows solving Boolean formulas in
   one go, but also adding constraints and query bindings of variables

   data-spacepart - space partitioning data structure[s] (initial
   release). Corey O'Connor [13]announced the [14]data-spacepart package,
   the goal of which is to be a collection of space partitioning data
   structures. Currently, there is only a simple quadtree implementation.

   Wired 0.2. Emil Axelsson [15]announced a new release of [16]Wired. The
   most important news in this release is that it now contains a 45nm cell
   library, which means that you can use Wired to create and analyze
   modern VLSI designs today!

   CFP Haskell Symposium 2009. Stephanie Weirich [17]announced a call for
   papers for the [18]2009 Haskell Symposium in Edinburgh, Scotland. The
   deadline for submissions is May 8.

   testpack (first release). John Goerzen [19]announced the release of
   [20]testpack, a collection of a few utilities for tests: some tools to
   convert QuickCheck properties into HUnit test cases, and various
   shortcuts and tools to increase verbosity while running tests in both
   QuickCheck and HUnit.

   convertible (first release). John Goerzen [21]announced a new package,
   [22]convertible. At its heart, it's a very simple typeclass that's
   designed to enable a reasonable default conversion between two
   different types without having to remember a bunch of functions. The
   return type from this conversion is "Either ConvertError a", and
   conversions are expected to do sanity checking (such as bounds checking
   when converting to types like Int), so as to produce neither garbage
   nor exceptions as part of the conversion process. The package also
   includes instances of the Convertible typeclass for common type
   conversions. working with numeric types as well as dates and times.
   Notably, it has code to convert between System.Time types and their
   Data.Time siblings, and vice versa, a capability I found annoyingly
   lacking in the standard library.

   Progress with IDE. Juergen Nicklisch-Franken [23]announced that the
   [24]Leksah 0.4.0 pre-release is now available. Current features include
   a Haskell customized editor with candy, project management support
   based on Cabal, a visual editor for Cabal files, navigation aids, a
   module browser, session support, and more.

   Hayoo! beta 0.3. Timo B. [25]announced the next beta version 0.3 of
   [26]Hayoo!, the Haskell API search engine with find-as-you-type and
   suggestions. Hayoo! now works even if your browser does not support

   DecisionTree 0.0. Adrian Neumann [27]announced the [28]DecisionTree
   package, which provides an implementation of the ID3 algorithm and can
   be used to classify data with discrete valued attributes.

   orchid-0.0.7. Sebastiaan Visser [29]announced a new release of
   [30]Orchid, just another Haskell Wiki. This release features a number
   of improvements, including a [31]filestore backend, searching, deleting
   and renaming support, and more. Check out the [32]demo.

   gitit 0.5. John MacFarlane [33]announced the latest release of
   [34]Gitit, the multitalented distributed wiki written in Haskell. This
   release uses the [35]filestore library and hence also supports a darcs
   backend, and also features optimizations, better search, better diffs,
   and more. You can check out a [36]running example.

   filestore 0.1. Gwern Branwen [37]announced [38]filestore 0.1, which
   provides a uniform, abstract, generic interface for storing versioned
   files on disk. It allows calling programs to use generic commands to
   store strings or binary data and perform various queries, such as 'what
   files are in this repository?' or 'what were the contents of this file
   at revision XXXXXXX?' or 'give me a diff of this file between revision
   XXXXXXX and revision YYYYYYY.' Because the interface is abstract, the
   calling program is insulated from the messy details of the backend
   (which might be a VCS or a database). Darcs and Git are fully
   supported. There are plans for a SQLite backend.

   Scurry :: A cross platform (if you put your mind to it) P2P VPN. John
   Van Enk [39]announced the release of [40]Scurry, a P2P VPN application
   written in Haskell (and a little C).


   Why binding to existing widget toolkits doesn't make any sense. Achim
   Schneider began an interesting [41]discussion on the proper approach to
   GUI toolkits in Haskell.

   Laws and partial values. Henning Thielemann began [42]a long thread on
   the semantics of laws (such as the monoid laws).

Blog noise

   [43]Haskell news from the [44]blogosphere.
     * Sebastian Fischer: [45]Using SmallCheck to Shatter an Audacious
     * Xmonad: [46]Quad head xmonad.
     * Darcs: [47]darcs weekly news #15.
     * Osfameron: [48]More longest paths, and sick folds..
     * Eric Kow (kowey): [49]haskell-ji.
     * Jeff Heard: [50]Control.Monad.IfElse.
     * Conal Elliott: [51]What is automatic differentiation, and why does
       it work?.
     * Luke Palmer: [52]Fun with PiSigma.
     * Neil Mitchell: [53]Small scripts with Haskell.
     * LHC Team: [54]Release notes..
     * LHC Team: [55]Thoughts on a new code generator.
     * Xmonad: [56]contribs review: ThreeColumnsMiddle, CenteredMaster,
     * Osfameron: [57]There's the nub (snippet in Perl and Haskell).
     * Malcolm Wallace: [58]codec implementations.
     * Sebastian Fischer: [59]Fun with Infinite Global Constants.
       Just-in-time, memoized binomial coefficients.
     * Chris Done: [60]Some libgd changes.
     * Luke Palmer: [61]A world without orphans. Luke muses on the
       benefits to be gained by outlawing orphan instances.
     * Creighton Hogg: [62]Fear of releasing code.
     * LHC Team: [63]Thoughts on a new code generator.
     * Don Stewart (dons): [64]What is Haskell good for?. Lots of things,
       if this tag cloud has anything to say about it.
     * Arch Haskell News: [65]Haskell wiki stack in Arch.
     * Conal Elliott: [66]Comparing formulations of higher-dimensional,
       higher-order derivatives.
     * Conal Elliott: [67]Fostering creativity by relinquishing the
     * Arch Haskell News: [68]Arch Haskell News: Jan 11 2009.
     * Dan Piponi (sigfpe): [69]Fast incremental regular expression
       matching with monoids. A very cool article showing how to use
       fingertrees storing memoized automaton transition functions to do
       fast incremental regular expression matching (or, in general, fast
       incremental lexing).

Quotes of the Week

     * lilac: is happy with his infinite type. it's ducks all the way
       across and down.
     * Gracenotes: You are likely to be eaten by a poset
     * RossMellgren: Apparently 64-bit GHC is sufficiently advanced to be
       indistinguishable from magic.
     * cjb: It's all fun and games until somebody loses an IOVar.
     * sigfpe: If I took some Ritalin, maybe I could write an entire book
       on Haskell and algebra.
     * ddarius: Nothing is evaluated until it is.

About the Haskell Weekly News

   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.

   To help create new editions of this newsletter, please see the
   information on [75]how to contribute. Send stories to byorgey at cis
   dot upenn dot edu. The darcs repository is available at darcs get
   [76]http://code.haskell.org/~byorgey/code/hwn/ .


   1. http://haskell.org/
   2. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51664
   3. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC
   4. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC%2Dsqlite3
   5. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC%2Dpostgresql
   6. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC%2Dodbc
   7. http://software.complete.org/software/wiki/hdbc/NewIn20
   8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51646
   9. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/emgm
  10. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51564
  11. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/incremental-sat-solver
  12. http://en.wikipedia.org/wiki/DPLL_algorithm
  13. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51505
  14. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-spacepart
  15. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51484
  16. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Wired
  17. http://article.gmane.org/gmane.comp.lang.haskell.general/16818
  18. http://haskell.org/haskell-symposium/2009/
  19. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51482
  20. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/testpack
  21. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51481
  22. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/convertible
  23. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51475
  24. http://www.leksah.org/
  25. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51450
  26. http://holumbus.fh-wedel.de/hayoo
  27. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51407
  28. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/DecisionTree
  29. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51395
  30. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/orchid
  31. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/filestore
  32. http://funct.org/wiki/
  33. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51392
  34. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/gitit
  35. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/filestore
  36. http://gitit.johnmacfarlane.net/
  37. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51388
  38. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/filestore
  39. http://article.gmane.org/gmane.comp.lang.haskell.cafe/51364
  40. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Scurry
  41. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/51478
  42. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/51299
  43. http://planet.haskell.org/
  44. http://haskell.org/haskellwiki/Blog_articles
  45. http://www-ps.informatik.uni-kiel.de/~sebf/haskell/smallcheck-experience.html
  46. http://xmonad.wordpress.com/2009/01/31/quad-head-xmonad/
  47. http://blog.darcs.net/2009/01/darcs-weekly-news-15.html
  48. http://greenokapi.net/blog/2009/01/31/more-longest-paths-and-sick-folds/
  49. http://koweycode.blogspot.com/2009/01/haskell-ji.html
  50. http://vis.renci.org/jeff/?p=96
  51. http://conal.net/blog/posts/what-is-automatic-differentiation-and-why-does-it-work/
  52. http://lukepalmer.wordpress.com/2009/01/28/fun-wth/
  53. http://neilmitchell.blogspot.com/2009/01/small-scripts-with-haskell.html
  54. http://lhc-compiler.blogspot.com/2009/01/release-notes.html
  55. http://lhc-compiler.blogspot.com/2009/01/thoughts-on-new-code-generator.html
  56. http://xmonad.wordpress.com/2009/01/27/contribs-review-threecolumnsmiddle-centeredmaster-mosaic/
  57. http://greenokapi.net/blog/2009/01/27/theres-the-nub-snippet-in-perl-and-haskell/
  58. http://feeds.feedburner.com/~r/malcolm/~3/523603226/codec-implementations.html
  59. http://www-ps.informatik.uni-kiel.de/~sebf/haskell/infinite-constants.html
  60. http://chrisdone.com/blog/2009/01/26/Some-libgd-changes
  61. http://lukepalmer.wordpress.com/2009/01/25/a-world-without-orphans/
  62. http://abstractabsurd.blogspot.com/2009/01/fear-of-releasing-code.html
  63. http://lhc-compiler.blogspot.com/2009/01/thoughts-on-new-code-generator.html
  64. http://donsbot.wordpress.com/2009/01/24/what-is-haskell-good-for/
  65. http://archhaskell.wordpress.com/2009/01/25/haskell-wiki-stack-in-arch/
  66. http://conal.net/blog/posts/comparing-formulations-of-higher-dimensional-higher-order-derivatives/
  67. http://conal.net/blog/posts/fostering-creativity-by-relinquishing-the-obvious/
  68. http://archhaskell.wordpress.com/2009/01/11/arch-haskell-news-jan-11-2009/
  69. http://sigfpe.blogspot.com/2009/01/fast-incremental-regular-expression.html
  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://haskell.org/haskellwiki/HWN
  76. http://code.haskell.org/~byorgey/code/hwn/

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