Slug function

sample.php

<?php
echo slug('João Batista Neto'); //joao-batista-neto

slug.php

<?php
/**
 * Check if a given string is utf8
 * @param string $string
 * @return boolean
 */
function is_utf8( $string ){
    return preg_match('%^(?:
                      [\x09\x0A\x0D\x20-\x7E] |
                      [\xC2-\xDF][\x80-\xBF] |
                      \xE0[\xA0-\xBF][\x80-\xBF] |
                      [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2} |
                      \xED[\x80-\x9F][\x80-\xBF] |
                      \xF0[\x90-\xBF][\x80-\xBF]{2} |
                      [\xF1-\xF3][\x80-\xBF]{3} |
                      \xF4[\x80-\x8F][\x80-\xBF]{2})*$%xs',
                      $string);
}

/**
 * Remove diacritics (accents) from a string.
 * @param string $string
 * @return string
 */
function remove_diacritics($string) {
    return preg_replace(array('/\xc3[\x80-\x85]/', //upper case
                              '/\xc3\x87/',
                              '/\xc3[\x88-\x8b]/',
                              '/\xc3[\x8c-\x8f]/',
                              '/\xc3([\x92-\x96]|\x98)/',
                              '/\xc3[\x99-\x9c]/',
                              '/\xc3[\xa0-\xa5]/', //lower case
                              '/\xc3\xa7/',
                              '/\xc3[\xa8-\xab]/',
                              '/\xc3[\xac-\xaf]/',
                              '/\xc3([\xb2-\xb6]|\xb8)/',
                              '/\xc3[\xb9-\xbc]/'),
                        str_split('ACEIOUaceiou', 1),
                        is_utf8( $string ) ? $string : utf8_encode($string));
}

/**
 * Creates a "slug" from a string
 * @param string $string
 * @return string
 */
function slug($string) {
    return return preg_replace(array('/[^a-z0-9]/', '/-{2,}/'), '-', strtolower(remove_diacritics($string)));
}