News in the Rakudo 2012.05 release

The Rakudo Star release 2012.05 comes with many improvements to the compiler. Some people have asked what they mean, so I want to explain some of them here.

The new -I and -M allow manipulation of the library search path and loading of modules, similar to Perl 5.

perl6 -Ilib t/yourtest.t  # finds your module under lib/

If you want to manipulate the search path from inside a script or module, you can now use the new lib module, again known from Perl 5.

# file t/yourtest.t;
use v6;
use lib 't/lib'; # now can load testing modules from t/lib/Yourmodule/Test.pm
use Yourmodule::Test;
...

If you look at how lib.pm is implemented, you'll notice another new feature: the ability to write a custom EXPORT subroutine -- necessary exactly for things like lib.pm.

But normal exporting and importing is now handled quite well from Rakudo. You can now mark routines as being exported to certain tag names:

module CGI {
    sub h1($text) is export(:HTML) { '<h1>' ~ $text ~ '</h1>' }
    sub param($key) is export { ... };
}

If you want to get only the HTML generating function(s), you can write

use CGI :HTML;

S11 has more details on the exporting and importing mechanism.

You can also import from within a single file by using import instead of use:

module Greeter {
    sub hello($who) is export {
        say "Hello $who";
    }
}

import Greeter; # make sub hello available in the current scope
hello('Perl 6 fans');