Haskell Weekly News: March 27, 2006

Submitted by dons on Tue, 03/28/2006 - 9:53pm.

Haskell Weekly News: March 27, 2006

Greetings, and thanks for reading issue 30 of HWN, a weekly newsletter covering developments in the Haskell community. Each Monday, new editions are posted to the Haskell mailing list and to The Haskell Sequence. RSS is also available.

A busy, exciting week!


  • monadLib 2.0. Iavor Diatchki announced the release of monadLib 2.0 -- library of monad transformers for Haskell. 'monadLib' is a descendent of 'mtl', the monad template library that is distributed with most Haskell implementations. Check out the library web page.

  • Text.Regex.Lazy (0.33). Chris Kuklewicz announced the release of Text.Regex.Lazy. This is an alternative to Text.Regex along with some enhancements. GHC's Text.Regex marshals the data back and forth to C arrays, to call libc. This is far too slow (and strict). This module understands regular expression Strings via a Parsec parser and creates an internal data structure (Text.Regex.Lazy.Pattern). This is then transformed into a Parsec parser to process the input String, or into a DFA table for matching against the input String or FastPackedString. The input string is consumed lazily, so it may be an arbitrarily long or infinite source.

  • HDBC 0.99.2. John Goerzen released HDBC 0.99.2, along with 0.99.2 versions of all database backends. John says "If things go well, after a few weeks of testing, this version will become HDBC 1.0.0". HDBC is a multi-database interface system for Haskell.

  • Planet Haskell. Isaac Jones asked if someone could volunteer to set up "Planet Haskell", an RSS feed aggregator in the style of Planet Debian, Planet Gnome or Planet Perl. Happily, Antti-Juhani Kaijanaho stepped up, and now Planet Haskell is live at http://planet.haskell.org. Antti-Juhani asks that any Haskell people with blogs submit their feed urls to him, so check it out!

  • Haskell on Gentoo Linux Duncan Coutts writes that GHC 6.4.1 has been marked stable on x86, amd64, sparc and ppc, for Gentoo Linux. (We also support ppc64, alpha and hppa.) Gentoo also has a collection of over 30 Haskell libraries and tools. There is also a #gentoo-haskell irc channel on freenode.

  • Concurrent Yhc. The Yhc dev team reports that Yhc now includes support for concurrency! The interface is the same as Concurrent GHC. Currently only

    • Control.Concurrent
    • Control.Concurrent.MVar
    • Control.Concurrent.QSem

    are implemented, however many other abstractions can be written in Haskell in terms of MVars.

  • GHC 6.4.2 Release Candidates Simon Marlow announced that GHC was moving into release-candidate mode for version 6.4.2. Grab a snapshot and try it out. The available builds are: x86_64-unknown-linux (Fedora Core 5), i386-unknown-linux (glibc 2.3 era), and Windows (i386-unknown-mingw32). Barring any serious hiccups, the release should be out in a couple of weeks.

  • HaRe 0.3. Sneaking out without us noticing, in January, a new snapshot of HaRe, the Haskell refactoring tool, was released. This snapshot of HaRe 0.3 is now compatible with the latest GHC and Programmatica. New refactorings have also been added.


This section covers activity on Haskell' standardisation process.


  • Disruptive Haskell. Paul Johnson forked a long discussion on how Haskell can be seen as a disruptive technology, and what Haskell's "brand" might be. Many interesting contributions were made.

  • Bit streaming Haskell. Per Gustafsson, having made a proposal to extend the Erlang `binary' data type from being a sequence of bytes (a byte stream) to being a sequence of bits (a bitstream), with the ability to do pattern matching at the bit level, asked for help writing efficient (and beautiful) Haskell versions of his bitstream benchmarks. Several improved programs were submitted, bringing the Haskell code into line with the OCaml and Erlang entries.

Quotes of the Week

Pseudonym's condensed LtU guide to the static types vs dynamic types debate:

  • Haskell-vs-Scheme is an issue on which reasonable people differ.
  • Ruby-vs-Java is an issue on which unreasonable people differ.
Everything else is details. :-)

Seen on #haskell:

shapr :: Science News had an article about a tribe of isolated villagers
in Brazil that don't have recursion or indirection in their language.

Contributing to HWN

You can help us create new editions of this newsletter. Please see the contributing information, send stories to dons -at- cse.unsw.edu.au. The darcs repository is available at darcs get http://www.cse.unsw.edu.au/~dons/code/hwn