1: <?php
2: /**
3: * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
4: * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
5: *
6: * Licensed under The MIT License
7: * For full copyright and license information, please see the LICENSE.txt
8: * Redistributions of files must retain the above copyright notice.
9: *
10: * @copyright Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
11: * @link https://cakephp.org CakePHP(tm) Project
12: * @since 3.0.0
13: * @license https://opensource.org/licenses/mit-license.php MIT License
14: */
15: namespace Cake\Database;
16:
17: /**
18: * An interface used by Expression objects.
19: */
20: interface ExpressionInterface
21: {
22: /**
23: * Converts the Node into a SQL string fragment.
24: *
25: * @param \Cake\Database\ValueBinder $generator Placeholder generator object
26: * @return string
27: */
28: public function sql(ValueBinder $generator);
29:
30: /**
31: * Iterates over each part of the expression recursively for every
32: * level of the expressions tree and executes the $visitor callable
33: * passing as first parameter the instance of the expression currently
34: * being iterated.
35: *
36: * @param callable $visitor The callable to apply to all nodes.
37: * @return void
38: */
39: public function traverse(callable $visitor);
40: }
41: