#!/usr/bin/perl -w

use strict;
use Benchmark;

my @data = qw{1949 1950 1951 1999 2000 2001 2010 2049 2050 2051 2102 22102 19534 19080 20010};

sub grinder() {
        foreach( @data ) {
            chomp;
            print "$_ ",  /^(19[5-9]\d|20([0-4]\d|50))$/ ? "ok\n" : "nok\n";
        }
}
sub roger() {
        foreach (@data) {
                chomp;
                print "$_ ", /^(?:19|20)(?:(?:(?<=19)[5-9]|(?<=20)[0-4])[0-9]|50)/x ? "Ok\n" : "not ok\n";
        }
}
sub posixguy() {
        foreach (@data) {
                chomp;
                print "$_ ", /^(19[5-9]\d)|(20([0-4]\d)|50)$/ ? "ok\n" : "nok\n";
        }
}
sub abigail() {
        foreach (@data) {
                chomp;
                local $" = "|";
                print "$_ ", /^(?:@{[1950 .. 2050]})$/ ? "ok\n" : "nok\n";
        }
}

timethese(10000, {grinder=>'grinder()', roger=>'roger()', posixguy=>'posixguy()', abigail=>'abigail()'});