Constraint.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;
 
interface Constraint
{
    const MATCH_NONE = "none";
 
    const MATCH_ANY = "any";
 
    const MATCH_ALL = "all";
 
    public function validate($value, $citationNumber = null);
}