IsNumeric.php

<?php
/*
 * citeproc-php
 *
 * @link        http://github.com/seboettg/citeproc-php for the source repository
 * @copyright   Copyright (c) 2016 Sebastian Böttger.
 * @license     https://opensource.org/licenses/MIT
 */
 
namespace Seboettg\CiteProc\Constraint;
 
use NumberFormatter;
use Seboettg\CiteProc\CiteProc;
use Seboettg\CiteProc\Util\NumberHelper;
use stdClass;
 
class IsNumeric extends AbstractConstraint
{
 
    protected function matchForVariable($variable, $data)
    {
        if (isset($data->{$variable})) {
            return $this->parseValue($data->{$variable});
        }
        return false;
    }
 
    private function parseValue($evalValue)
    {
        if (is_numeric($evalValue)) {
            return true;
        } elseif (preg_match(NumberHelper::PATTERN_ORDINAL, $evalValue)) {
            $numberFormatter = new NumberFormatter(
                CiteProc::getContext()->getLocale()->getLanguage(),
                NumberFormatter::ORDINAL
            );
            return $numberFormatter->parse($evalValue) !== false;
        } elseif (preg_match(NumberHelper::PATTERN_ROMAN, $evalValue)) {
            return NumberHelper::roman2Dec($evalValue) !== false;
        } elseif (preg_match(NumberHelper::PATTERN_COMMA_AMPERSAND_RANGE, $evalValue)) {
            return true;
        }
        return false;
    }
}