The second example you showed ...

sub get_captures {
    my ($pattern, $line) = @_;
    my @captures = $line =~ m/($pattern)/;
    shift(@captures);
    return @captures;
}
[download]

... won't work in the production code of which my code presented here is a sample. That's because it would impose upon my users an unnecessary and likely-to-be-forgotten requirement: that they enclose the regex in parentheses so as to guarantee that at least one substring is captured.

More interesting is this approach, which you tucked away:

sub get_captures {
    my ($pattern, $line) = @_;
    my @captures = $line =~ m/$pattern/;
    return @captures[0 .. $#+ - 1];
}
[download]

Once I understand @+ and @- better, I'll see whether I like this better than Grandfather's suggestion.

Thank you very much.