tokenization of english numerals.php

<?php // regular expression for tokenization of english numerals from 1 to 999.999

$re = "/(?<=\W)(?:(?:(?:(?:(?:(?:(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine))) )?(hundred)s?)? ?(?:and )?(?:(?:(?:(?:(twenty)|(thirty)|(forty)|(fifty)|(sixty)|(seventy)|(eighty)|(ninety))(?:[- ]?(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine)))?)|(?:(?:(eleven)|(twelve)|(thirteen)|(fourteen)|(fifteen)|(sixteen)|(seventeen)|(eighteen)|(nineteen)))|(?:(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine)))|(?:(ten))))?) )?(thousand)s?)? ?(?:(?:(?:(?:(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine))) )?(hundred)s?)? ?(?:and )?(?:(?:(?:(?:(twenty)|(thirty)|(forty)|(fifty)|(sixty)|(seventy)|(eighty)|(ninety))(?:[- ]?(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine)))?)|(?:(?:(eleven)|(twelve)|(thirteen)|(fourteen)|(fifteen)|(sixteen)|(seventeen)|(eighteen)|(nineteen)))|(?:(?:(one)|(two)|(three)|(four)|(five)|(six)|(seven)|(eight)|(nine)))|(?:(ten))))?)? ?(?:and)? ?(?:(quarter)|(half)|(three quarter)s?)?(?=\W)/um";

// and tokens

$tokens = array(
    'one'   => 1,
    'two'   => 2,
    'three' => 3,
    'four'  => 4,
    'five'  => 5,
    'six'   => 6,
    'seven' => 7,
    'eight' => 8,
    'nine'  => 9,
    'ten'   => 10,
    'eleven'    => 11,
    'twelve'    => 12,
    'thirteen'  => 13,
    'fourteen'  => 14,
    'fifteen'   => 15,
    'sixteen'   => 16,
    'seventeen' => 17,
    'eighteen'  => 18,
    'nineteen'  => 19,
    'twenty'    => 20,
    'thirty'    => 30,
    'forty'     => 40,
    'fifty'     => 50,
    'sixty'     => 60,
    'seventy'   => 70,
    'eighty'    => 80,
    'ninety'    => 90,
    'hundred'   => 100,
    'thousand'  => 1000,
    'quarter'   => '0.25',
    'half'      => '0.5',
    'three quarter' => '0.75',
);