I came up with this:

sub prop3
{
    my $str = shift;
    my $level = shift || 0;
    return $str unless $level;  # 3rd update
    my @str = split(/[()]/, $str);
    splice @str, 0, $level;
    my $out = join('(', @str);
    $out .= ')' x ( @str - 1 );
    return $out;
}
[download]

But it's actually about 10% slower than the original. Go figure.


update: more testing - it really is slower. Very aggravating to me, since it looks like good clean code to me.


update again: Also came up with this, which is somewhat quicker, but uglier:

sub getpropstr
{
    local $_ = shift;
    my $level = shift || 0;
    if ( $level == -1 ) { /([^()]+)\)+$/; return $1 }
    while ( $level-- > 0)
    {
        chop;
        s/^[^(]+\(//;
    }
    return $_;
}
[download]

3rd update: line commented w/ '3rd update' in my first routine makes it closer to the same speed as the OP's original.

--Bob Niederman, http://bob-n.com