1: <?php
 2: 
 3: namespace Alchemy\core;
 4: 
 5: 
 6: /**
 7:  * Interface for SQL elements
 8:  */
 9: interface IElement {
10: 
11:     /**
12:      * Apply a tag to this element. The same tag cannot be applied
13:      * with two different values.
14:      *
15:      * @param string $tag
16:      * @param string $value optional value to give tag
17:      */
18:     public function addTag($tag, $value = true);
19: 
20: 
21:     /**
22:      * Get the locally-unique element id
23:      *
24:      * @return string
25:      */
26:     public function getID();
27: 
28: 
29:     /**
30:      * If the tag has been applied to this object, returns its
31:      * value, else false
32:      *
33:      * @param  string $tag tag name
34:      * @return mixed       value or false
35:      */
36:     public function getTag($tag);
37: 
38: 
39:     /**
40:      * List of all tags that apply to this element
41:      *
42:      * @return array
43:      */
44:     public function listTags();
45: }