[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
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Haskell Weekly News
http://sequence.complete.org/hwn/20090131
Issue 103 - January 31, 2009
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Welcome to issue 103 of HWN, a newsletter covering developments in the
[1]Haskell community.
Announcements
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
incrementally.
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
JavaScript.
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).
Discussion
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
Claim.
* 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,
Mosaic.
* 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
obvious.
* 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/ .
References
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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