use Benchmark 'cmpthese';

my $str = "alphabet X alphabet" x 100 . "junk at the end" x 10;
cmpthese(-5, {
  last => sub { my $x = $str; $x =~ s/([A-Z])[^A-Z]*$/$1/ },
  capt_repl => sub { my $x = $str; $x =~ s/(.*[A-Z]).*/$1/ },
  rx_rx => sub { my $x = $str; $x =~ /.*[A-Z]/g and $x =~ s/\G.*// },
  sexeger => sub {
    my $x = $str; ($x = reverse $x) =~ s/^[^A-Z]+//; $x = reverse $x;
  },
});

print "-------------- now a short one --------------------------------\n";

$str = "a very short one";
cmpthese(-5, {
  last => sub { my $x = $str; $x =~ s/([A-Z])[^A-Z]*$/$1/ },
  capt_repl => sub { my $x = $str; $x =~ s/(.*[A-Z]).*/$1/ },
  rx_rx => sub { my $x = $str; $x =~ /.*[A-Z]/g and $x =~ s/\G.*// },
  sexeger => sub {
    my $x = $str; ($x = reverse $x) =~ s/^[^A-Z]+//; $x = reverse $x;
  },
});

__END__

[16:10] <Joe>              Rate      last   sexeger capt_repl     rx_rx
[16:10] <Joe> last       4329/s        --      -78%      -82%      -86%
[16:10] <Joe> sexeger   19386/s      348%        --      -19%      -37%
[16:10] <Joe> capt_repl 23859/s      451%       23%        --      -22%
[16:10] <Joe> rx_rx     30778/s      611%       59%       29%        --
[16:10] <Joe> -------------- now a short one --------------------------------
[16:10] <Joe>               Rate   sexeger capt_repl     rx_rx      last
[16:10] <Joe> sexeger   261969/s        --       -4%       -6%      -70%
[16:10] <Joe> capt_repl 271691/s        4%        --       -3%      -68%
[16:10] <Joe> rx_rx     279271/s        7%        3%        --      -67%
[16:10] <Joe> last      859023/s      228%      216%      208%        --