A few days ago I wrote about my fun experiment trying to port facter to rakudo Perl 6. I said it was "almost completely functional".

Well, I was a bit optimistic, it seems :) It took me a few more nights of hacking, but in the end now it's almost completely functional :) It basically runs, I have ported a few facts from Facter's original ruby code too, like the kernel fact, or the physicalprocessorcount fact and other simple ones.

What's missing to declare the experiment successful is the implementation of confines. A confine in facter speak it's a specific restriction that applies to a fact. For example, the physicalprocessorcount fact reads some files from /proc, and that is only available on Linux. So, in this case, the confine rule for physicalprocessorcount is that the fact kernel must have "Linux" as its value. In code that becomes:

Facter.add("physicalprocessorcount", sub ($f) {
    $f.confine("kernel" => "Linux");
    $f.setcode(block => sub {
        Facter::Util::Resolution.exec('grep "physical id" /proc/cpuinfo|cut -d: -f 2|sort -u|wc -l');
    });
});

which is pretty similar to the Ruby counterpart:

Facter.add("physicalprocessorcount") do
    confine :kernel => :linux

    setcode do
        ppcount = Facter::Util::Resolution.exec('grep "physical id" /proc/cpuinfo|cut -d: -f 2|sort -u|wc -l')
    end
end

The Ruby version is still more elegant, but all in all I'm very happy with the outcome so far. It could probably be improved a lot too. Perl 6 is awesome. Get the code from http://github.com/cosimo/perl6-facter/ and feel free to ping me or comment if you want to know more.