For quite some time perl provided a form of
my declarations that
includes a type name, like this:
my Str $x = 'foo';
However, that didn't do anything useful, until Vincent Pit came along
and wrote the excellent
Lexical::Types
module, which allows you to extend the semantics of typed lexicals and
actually make them do something useful. For that, it simply invokes a
callback for every
my declaration with a type in the scopes it is
loaded. Within that callback you get the variable that is being
declared as well as the name of the type used in the declaration.
We also have Moose type constraints and the great
MooseX::Types module,
that allows us to define our own type libraries and import the type
constraints into other modules.
Let's glue those modules together. Consider this code:
use MooseX::Types::Moose qw/Int/;
use Lexical::Types;
my Int $x = 42;
The first problem is that the perl compiler expects a package with the
name of the type used in
my to exist. If there's no such package
compilation will fail.
Creating top-level namespaces for all the types we want to use would
obviously suck. Luckily the compiler will also try to look for a
function with the name of the type in the current scope. If that
exists and is inlineable, it will call that function and use the
return value as a package name.
In the above code snippet an
Int function already exists. We
imported that from
MooseX::Types::Moose. Unfortunately it isn't
inlineable. Even if it were, compilation would still fail, because it
would return a
Moose::Meta::TypeConstraint instead of a valid
package name.
To fix that, let's rewrite the code to this:
use MooseX::Types::Moose qw/Int/;
use MooseX::Lexical::Types qw/Int/;
my Int $x = 42;
Let's also write a MooseX::Lexical::Types module that replaces
existing imported type exports with something that can be inlined and
returns an existing package name based on the type constraint's name.
package MooseX::Lexical::Types;
use Class::MOP;
use MooseX::Types::Util qw/has_available_type_export/;
use namespace::autoclean;
sub import
my ($class, @args) = @_;
my $caller = caller();
my $meta = Class::MOP::class_of($caller) Class::MOP::Class->initialize($caller);
for my $type_name (@args)
my $type_constraint = has_available_type_export($caller, $type_name);
my $package = 'MooseX::Lexical::Types::TYPE::' . $type_constraint->name;
Class::MOP::Class->create($package);
$meta->add_package_symbol('&'.$type_name => sub () $package );
Lexical::Types->import;
1;
With that the example code now compiles. Unfortunately it breaks every
other usecase of MooseX::Types. The export will still need to return a
Moose::Meta::TypeConstraint at run time so this will continue to
work:
has some_attribute => (is => 'ro', isa => Int);
So instead of returning a plain package name from our exported
function we will return an object that delegates all method calls to
the actual type constraint, but evaluates to our special package name
when used as a string:
my $decorator = MooseX::Lexical::Types::TypeDecorator->new($type_constraint);
$meta->add_package_symbol('&'.$type_name => sub () $decorator );
and:
package MooseX::Lexical::Types::TypeDecorator;
use Moose;
use namespace::autoclean;
extends 'MooseX::Types::TypeDecorator';
use overload '""' => sub
'MooseX::Lexical::Types::TYPE::' . $_[0]->__type_constraint->name
;
1;
Now we're able to use
Int as usual and have Lexical::Types invoke
its callback on
MooseX::Lexical::Types::TYPE::Int. Within that
callback we will need the real type constraint again, but as it is
invoked as a class method with no good way to pass in additional
arguments, we will need to store the type constraint somewhere. I
choose to simply add a method to the type class we create when
constructing our export. After that, all we need is to implement our
Lexical::Types callback. We will put that in a class all our type
classes will inherit from:
Class::MOP::Class->create(
$package => (
superclasses => ['MooseX::Lexical::Types::TypedScalar'],
methods =>
get_type_constraint => sub $type_constraint ,
,
),
);
The Lexical::Types callback will now need to tie things together by
modifying the declared variable so it will automatically validate
values against the type constraint when being assigned to. There are
several ways of doing this. Using
tie on the declared variable
would probable be the easiest thing to do. However, I decided to use
Variable::Magic
(also written by Vincent Pit - did I mention he's awesome?), because
it's mostly invisible at the perl level and also performs rather well
(not that it'd matter, given that validation itself is relatively
slow):
package MooseX::Lexical::Types::TypedScalar;
use Carp qw/confess/;
use Variable::Magic qw/wizard cast/;
use namespace::autoclean;
my $wiz = wizard
data => sub $_[1]->get_type_constraint ,
set => sub
if (defined (my $msg = $_[1]->validate($ $_[0] )))
confess $msg;
();
;
sub TYPEDSCALAR
cast $_[1], $wiz, $_[0];
();
1;
With this, our example code now works. If someone wants to assign,
say,
'foo' to the variable declared as
my Int $x our magic
callback will be invoked, try to validate the value against the type
constraint and fail loudly. WIN!
The code for all this is available
github and should also
be on CPAN shortly.
You might notice warnings about mismatching prototypes. Those are
caused by Class::MOP and fixed in the git version of it, so they'll go
away with the next release.
There's still a couple of caveats, but please see
the documentation
for that.
A few of us are working on spam removal from Debian lists archives.
The wiki page linked above explains how to report spam on Debian mailing lists. This is in short as easy as bouncing a mail to a specific address, from your favourite MUA.
These "reported spams" then need to be reviewed. Once a given message has been identified as "spam" by enough DD's (there are many false positives in the candidates, particularly in non English-speaking mailing lists), it is removed from the archives.
Many mails have already been removed and any help is welcomed.
Since Frans Pop launched this for debian-boot, back in May, I use 1 or 2 hours every Sunday to this work. After working on debian-boot only, I gradually worked on reported spams in other lists. As of now, I only have 4 lists where I still have work to do:
So, next Saturday 
Speaking of Minas Gerais, it is, according to Wikipedia, the fourth in size among the 26 States of Brazil, being just a bit bigger than mainland-France. Minas Gerais is one of the main earth transports hubs of the country (having the largest number of federal roads), and is famous for its tasty food, the beauty of its people, its cheeses, the calm, introspective nature of its people, its interesting way of speaking portuguese, and its alcoholic beverages.
Now, going away from Rio to Belo Horizonte has a single big disadvantage associated with it: we don t get to have the Sea a few minutes away, anymore. Our solution to that is, of course, going to one of the numerous bars (the legend goes around that BH has the largest absolute number of bars of all cities in the world), and drinking instead of swimming! Quem n o tem mar, vai pro bar!
Just this week I went to the movies to check the 
How inspiring can that be?
You can find the original 
With any luck, someone has seen this problem before and can fix it easily. I don t seem to be able to find the fix by searching, but the search terms feel like they re either too general or too specific.
I was trying to install some perl software on a debian lenny system that was upgraded from etch (and previously from sarge). After installing the dependencies, I started getting errors like this:-
Since last weekend 
update:
One of my readers, Florian, sent this nice bit, which I have not read before:
“I read your blog via Planet Debian and immediately felt reminded of Jane
The strongly connected set of the GPG keys graph contains a bit more than 40000 keys now (yes, that’s a lot of geeks!). I wondered what was the biggest clique (complete subgraph) in that graph, and also of course the biggest clique I was in.
It’s easy to grab the whole web of trust 
Participiants: Martin F Krafft <madduck@madduck.net> (vcs-pkg.org), Florian Maier <contact@marsmenschen.com> (LiMux), Cesar Gomez <cesar.gomez@gmail.com> (Linex), Holger Levsen <holger@layer-acht.org> (Debian Edu), Andreas Tille <tille@debian.org>, Mark Shuttleworth <marks@debian.org> (Ubuntu), Bdale Garbee (Debian)
Another point release for Etch has been done; now it's the time for the CD
team to roll out new images after the next mirror pulse. The official
announcements (prepared by Alexander Reichle-Schmehl, thanks!) will follow
shortly afterwards. FTP master of the day was Joerg Jaspert, who
did his first point release since Woody, as he told us on IRC. We
appreciate your work and you spending your time that shortly before
going to Argentina.
This point release includes the etchnhalf update introducing a new kernel
image (based on 2.6.24) and some driver updates. Additionally the
infamous openssl hole will be fixed for good, even for new installs.
Again I want to present you a list of people who contributed to this
release. It cannot be complete as I got the information out of the
