1: <?php
 2: 
 3: namespace Alchemy\core\query;
 4: use Alchemy\core\Element;
 5: 
 6: 
 7: /**
 8:  * Class for composing expressions
 9:  */
10: class Expression extends Element {
11: 
12:     protected $elements = array();
13: 
14: 
15:     public static function __callStatic($name, $args) {
16:         $def = self::get_definition(trim(strtolower($name), '_'));
17:         $elements = (isset($args[0]) && is_array($args[0])) ? $args[0] : $args;
18: 
19:         return new $def['tags']['element.class']($def['tags']['element.type'], $elements);
20:     }
21: 
22: 
23:     public function __construct($type, array $elements) {
24:         parent::__construct($type);
25:         $cls = get_called_class();
26: 
27:         $def = self::get_definition($type);
28:         $tag = $def['tags']['expr.element'];
29: 
30:         if ($def['arity'] != -1 && $def['arity'] != count($elements)) {
31:             throw new \Exception("{$cls} '{$type}': Expected {$def['arity']} elements, got " . count($elements));
32:         }
33: 
34:         foreach ($elements as $element) {
35:             if (!$element->getTag($tag)) {
36:                 throw new \Exception("{$cls} '{$type}': Expected '{$tag}' at position {$key}");
37:             }
38:         }
39: 
40:         $this->elements = $elements;
41:     }
42: 
43: 
44:     public function getDescription($maxdepth = 3, $curdepth = 0) {
45:         $str = parent::getDescription($maxdepth, $curdepth);
46: 
47:         if ($curdepth <= $maxdepth) {
48:             $i = str_repeat('  ', $curdepth);
49:             $elements = array();
50:             foreach($this->elements as $element) {
51:                 $elements[] = $element->getDescription($maxdepth, $curdepth + 1);
52:             }
53: 
54:             $str .= " [\n$i  ".implode(",\n$i  ", $elements)."\n$i]";
55:         }
56: 
57:         return $str;
58:     }
59: 
60: 
61:     public function elements() {
62:         return $this->elements;
63:     }
64: 
65: 
66:     /**
67:      * Recursively get all scalar parameters used by this expression
68:      *
69:      * @return array array(Scalar, Scalar, ...)
70:      */
71:     public function parameters() {
72:         $params = array();
73: 
74:         foreach ($this->elements as $element) {
75:             if (method_exists($element, 'parameters')) {
76:                 $params = array_merge($params, $element->parameters());
77:             }
78:         }
79: 
80:         return $params;
81:     }
82: 
83: 
84:     public function tables() {
85:         $tables = array();
86: 
87:         foreach($this->elements as $element) {
88:             if ($element instanceof Expression) {
89:                 $tables += $element->tables();
90:             } elseif ($element instanceof ColumnRef) {
91:                 $tables[$element->table()->getID()] = $element->table();
92:             }
93:         }
94: 
95:         return $tables;
96:     }
97: }
98: