[Haskell] Haskell Weekly News: Issue 103 - January 31, 2009
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
HDBC v2.0 now available. John Goerzen announced that HDBC v2.0 is
now available. Simultaneously, HDBC-sqlite3, HDBC-postgresql, and
HDBC-odbc v2.0 have also been uploaded to Hackage. A guide to new
features and migration can be found here.
Extensible and Modular Generics for the Masses: emgm-0.2. Sean Leather
announced the second major release of 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 announced the
incremental-sat-solver library, which provides an implementation of
the 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 announced the 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 announced a new release of 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 announced a call for
papers for the 2009 Haskell Symposium in Edinburgh, Scotland. The
deadline for submissions is May 8.
testpack (first release). John Goerzen announced the release of
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 announced a new package,
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 announced that the
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. announced the next beta version 0.3 of
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 announced the 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 announced a new release of
Orchid, just another Haskell Wiki. This release features a number
of improvements, including a filestore backend, searching, deleting
and renaming support, and more. Check out the demo.
gitit 0.5. John MacFarlane announced the latest release of
Gitit, the multitalented distributed wiki written in Haskell. This
release uses the filestore library and hence also supports a darcs
backend, and also features optimizations, better search, better diffs,
and more. You can check out a running example.
filestore 0.1. Gwern Branwen announced 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 announced the release of 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 discussion on the proper approach to
GUI toolkits in Haskell.
Laws and partial values. Henning Thielemann began a long thread on
the semantics of laws (such as the monoid laws).
Haskell news from the blogosphere.
* Sebastian Fischer: Using SmallCheck to Shatter an Audacious
* Xmonad: Quad head xmonad.
* Darcs: darcs weekly news #15.
* Osfameron: More longest paths, and sick folds..
* Eric Kow (kowey): haskell-ji.
* Jeff Heard: Control.Monad.IfElse.
* Conal Elliott: What is automatic differentiation, and why does
* Luke Palmer: Fun with PiSigma.
* Neil Mitchell: Small scripts with Haskell.
* LHC Team: Release notes..
* LHC Team: Thoughts on a new code generator.
* Xmonad: contribs review: ThreeColumnsMiddle, CenteredMaster,
* Osfameron: There's the nub (snippet in Perl and Haskell).
* Malcolm Wallace: codec implementations.
* Sebastian Fischer: Fun with Infinite Global Constants.
Just-in-time, memoized binomial coefficients.
* Chris Done: Some libgd changes.
* Luke Palmer: A world without orphans. Luke muses on the
benefits to be gained by outlawing orphan instances.
* Creighton Hogg: Fear of releasing code.
* LHC Team: Thoughts on a new code generator.
* Don Stewart (dons): What is Haskell good for?. Lots of things,
if this tag cloud has anything to say about it.
* Arch Haskell News: Haskell wiki stack in Arch.
* Conal Elliott: Comparing formulations of higher-dimensional,
* Conal Elliott: Fostering creativity by relinquishing the
* Arch Haskell News: Arch Haskell News: Jan 11 2009.
* Dan Piponi (sigfpe): 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
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.
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