It'll be in Perl6 and is available now in Perl6::Rules. From the perldoc:

An interpolated array:

    use Perl6::Rules;
    @cmds = ('get','put','save','load','dump','quit');
    $str =~ m/ @::cmds /;
[download]

matches if any of its elements eq matches the string at that point. So the above example is equivalent to:

    $str =~ /get|put|save|load|dump|quit/;
[download]