in reply to Peeling the Peelings

The following should do what you want if the input is in the format you specify, i.e. nested function with single arguments.

my $example1 = 'this(is(a(test)))';

foreach (0..4) {
    print "level $_: '", peel($example1, $_), "'\n";
}
print "level -1: '", peel($example1, -1), "'\n";

sub peel {
    my ($str, $level) = @_;
    if ($level < 0) {
        $str =~ /([^\(\)]+)\)+\Z/;
        return $1;
    }
    my $opening = '(?:[^\(]+\(){' . $level . '}';
    my $closing = '\){' . $level . '}';
    $str =~ /\A$opening(.+?)$closing\Z/;
    return $1;
}

[download]

Hope this helps, -gjb-

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Re: Re: Peeling the Peelings
by waswas-fng (Curate) on Jul 01, 2003 at 21:01 UTC 
                   Rate Peel Get_Proparg
Peel         1359/s    --   -76%
Get_Proparg  5780/s  325%    --

    [download]
    Looks like thats a wee bit slower.

    -Waswas
[reply]
[d/l]

      It's easy to optimize a bit, although it's still 20% slower than Aristotle's version :-(

      my %cache = ('-1' => qr/([^\(\)]+)\)+\Z/);

sub peel {
  my $str = shift;
  my $level = shift || 0;
  if (!exists $cache{$level}) {
    my $opening = '[^\(]+\(' x $level;
    my $closing = '\)' x $level;
    $cache{$level} = qr/\A$opening(.+?)$closing\Z/;
  }
  $str =~ $cache{$level};
  return $1;
}

      [download]
      The benchmark results are: 
                   Rate   Fatvamp       gjb      bobn Aristotle
Fatvamp   21155/s        --      -14%      -17%      -28%
gjb       24631/s       16%        --       -3%      -16%
bobn      25523/s       21%        4%        --      -13%
Aristotle 29497/s       39%       20%       16%        --

      [download]

      Best regards, -gjb-

[reply]
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