cakephp/Cake/Database/ExpressionInterface.php

<?php
/**
 * PHP Version 5.4
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         CakePHP(tm) v 3.0.0
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */
namespace Cake\Database;

/**
 * An interface used by Expression objects.
 */
interface ExpressionInterface {

/**
 * Converts the Node into a SQL string fragment.
 *
 * @param Cake\Database\ValueBinder $generator Placeholder generator object
 * @return string
 */
	public function sql(ValueBinder $generator);

/**
 * Iterates over each part of the expression recursively for every
 * level of the expressions tree and executes the $visitor callable
 * passing as first parameter the instance of the expression currently
 * being iterated.
 *
 * @param callable $visitor
 * @return void
 */
	public function traverse(callable $visitor);

}