use v5.14;
use re "/sixm";

$_ = "This part is past all of this paaRTy of the string. Paaaaarty on!";

my @matches = ();
sub show_matches {
    printf "Got %d matches:\n", scalar @matches;
    my $i = 1;
    for (@matches) {
        printf "   %2d\t$_\n", $i++, $_;
    }
}

    @matches = /      pa .*  rt         /g;
show_matches();

    @matches = /      pa .*? rt         /g;
show_matches();

    @matches = / (?= (pa .*  rt) )      /g;
show_matches();

    @matches = ();
          () = /      (pa .* rt)
                (?{push @matches, $^N})
                      (*FAIL)
                                        /g;
show_matches();