Announce: Rakudo Perl 6 development release #21 ("Seattle")

On behalf of the Rakudo development team, I'm pleased to announce
the September 2009 development release of Rakudo Perl #21 "Seattle".
Rakudo is an implementation of Perl 6 on the Parrot Virtual Machine [1].
The tarball for the September 2009 release is available from
http://github.com/rakudo/rakudo/downloads .

Due to the continued rapid pace of Rakudo development and the frequent
addition of new Perl 6 features and bugfixes, we recommend building Rakudo
from the latest source, available from the main repository at github.
More details are available at http://rakudo.org/how-to-get-rakudo.

Rakudo Perl follows a monthly release cycle, with each release code named
after a Perl Mongers group.  September 2009 is code named "Seattle" for the
enthusiasm they have shown for Perl 6 during monthly meetings, and the
feedback, encouragement and support given me for the past several years.

Since the 2009-08 release, Rakudo Perl builds from an "installed
Parrot" instead of using Parrot's build tree.  This release of Rakudo
requires Parrot 1.6.0.  For the latest information on building and
using Rakudo Perl, see the README file section titled "Building and
invoking Rakudo".  (Quick note: the "--gen-parrot" option still
automatically downloads and builds Parrot as before, if you prefer
that approach.)

Also, unlike previous versions of Rakudo Perl, the "perl6"
(or "perl6.exe") executables only work when invoked from the
Rakudo root directory until a "make install" is performed.
Running "make install" will install Rakudo and its libraries
into the Parrot installation that was used to build it, and then
the executables will work when invoked from any directory.

Some of the specific major changes and improvements occuring
with this release include:
  
* Rakudo is now passing 15,497 spectests, an increase of 3,128
  passing tests since the August 2009 release.  With this release
  Rakudo is now passing 71.5% of the available spectest suite.

* Rakudo now supports contextual variables.

* Rakudo now supports the rational (Rat) data type.

* Rakudo now supports overloading of many of the builtin operators,
  many of which are now defined in the core setting.  Many have
  also been improved to be more faithful to the specification
  with respect to types and coercions.

* Substantially improved support for trait handling.  Most of the
  "built-in" traits are now defined in the core setting.

* The %*ENV variable now works properly for modifying the process environment.

Since the Perl 6 specification is still in flux, some deprecated features
have been removed from Rakudo. Prominently among those are:

 * '=$handle' is deprecated in favor of '$handle.get' (one line)
   and '$handle.lines' (all lines).

 * 'int $obj' is deprecated in favor of '$obj.Int'.

The development team thanks all of our contributors and sponsors for
making Rakudo Perl possible.  If you would like to contribute,
see http://rakudo.org/how-to-help , ask on the perl6-compiler@perl.org
mailing list, or ask on IRC #perl6 on freenode.

The next release of Rakudo (#22) is scheduled for October 22, 2009.
A list of the other planned release dates and codenames for 2009 is
available in the "docs/release_guide.pod" file.  In general, Rakudo
development releases are scheduled to occur two days after each
Parrot monthly release.  Parrot releases the third Tuesday of each month.

Have fun!

References:
[1]  Parrot, http://parrot.org/
