| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  | /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  * Picos Twig extension to implement additional filters | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  |  * @author  Daniel Rudolf | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  |  * @link    http://picocms.org | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  |  * @license http://opensource.org/licenses/MIT | 
            
                                                                                                            
                            
            
                                    
            
            
                | 9 |  |  |  * @version 1.0 | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  | class PicoTwigExtension extends Twig_Extension | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  | { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  |      * Current instance of Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  |      * @see PicoTwigExtension::getPico() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  |      * @var Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  |     private $pico; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |      * Constructs a new instance of this Twig extension | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  |      * @param Pico $pico current instance of Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |     public function __construct(Pico $pico) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |         $this->pico = $pico; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  |      * Returns the extensions instance of Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  |      * @see    Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 35 |  |  |      * @return Pico the extensions instance of Pico | 
            
                                                                                                            
                            
            
                                    
            
            
                | 36 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  |     public function getPico() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 38 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 39 |  |  |         return $this->pico; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 40 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 41 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 42 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |      * Returns the name of the extension | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |      * @see    Twig_ExtensionInterface::getName() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 46 |  |  |      * @return string the extension name | 
            
                                                                                                            
                            
            
                                    
            
            
                | 47 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 48 |  |  |     public function getName() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 49 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 50 |  |  |         return 'PicoTwigExtension'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 51 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 52 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 53 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 54 |  |  |      * Returns the Twig filters markdown, map and sort_by | 
            
                                                                                                            
                            
            
                                    
            
            
                | 55 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 56 |  |  |      * @see    Twig_ExtensionInterface::getFilters() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 57 |  |  |      * @return Twig_SimpleFilter[] array of Picos Twig filters | 
            
                                                                                                            
                            
            
                                    
            
            
                | 58 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 59 |  |  |     public function getFilters() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 60 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 61 |  |  |         return array( | 
                            
                    |  |  |  | 
                                                                                        
                                                                                     | 
            
                                                                                                            
                            
            
                                    
            
            
                | 62 |  |  |             'markdown' => new Twig_SimpleFilter('markdown', array($this, 'markdownFilter')), | 
            
                                                                                                            
                            
            
                                    
            
            
                | 63 |  |  |             'map' => new Twig_SimpleFilter('map', array($this, 'mapFilter')), | 
            
                                                                                                            
                            
            
                                    
            
            
                | 64 |  |  |             'sort_by' => new Twig_SimpleFilter('sort_by', array($this, 'sortByFilter')), | 
            
                                                                                                            
                            
            
                                    
            
            
                | 65 |  |  |         ); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 66 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 67 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 68 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 69 |  |  |      * Parses a markdown string to HTML | 
            
                                                                                                            
                            
            
                                    
            
            
                | 70 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 71 |  |  |      * This method is registered as the Twig `markdown` filter. You can use it | 
            
                                                                                                            
                            
            
                                    
            
            
                | 72 |  |  |      * to e.g. parse a meta variable (`{{ meta.description|markdown }}`). | 
            
                                                                                                            
                            
            
                                    
            
            
                | 73 |  |  |      * Don't use it to parse the contents of a page, use the `content` filter | 
            
                                                                                                            
                            
            
                                    
            
            
                | 74 |  |  |      * instead, what ensures the proper preparation of the contents. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 75 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 76 |  |  |      * @param  string $markdown markdown to parse | 
            
                                                                                                            
                            
            
                                    
            
            
                | 77 |  |  |      * @return string           parsed HTML | 
            
                                                                                                            
                            
            
                                    
            
            
                | 78 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 79 |  |  |     public function markdownFilter($markdown) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 80 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 81 |  |  |         if ($this->getPico()->getParsedown() === null) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 82 |  |  |             throw new LogicException( | 
            
                                                                                                            
                            
            
                                    
            
            
                | 83 |  |  |                 'Unable to apply Twig "markdown" filter: ' | 
            
                                                                                                            
                            
            
                                    
            
            
                | 84 |  |  |                 . 'Parsedown instance wasn\'t registered yet' | 
            
                                                                                                            
                            
            
                                    
            
            
                | 85 |  |  |             ); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 86 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 87 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 88 |  |  |         return $this->getPico()->getParsedown()->text($markdown); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 89 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 90 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 91 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 92 |  |  |      * Returns a array with the values of the given key or key path | 
            
                                                                                                            
                            
            
                                    
            
            
                | 93 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 94 |  |  |      * This method is registered as the Twig `map` filter. You can use this | 
            
                                                                                                            
                            
            
                                    
            
            
                | 95 |  |  |      * filter to e.g. get all page titles (`{{ pages|map("title") }}`). | 
            
                                                                                                            
                            
            
                                    
            
            
                | 96 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 97 |  |  |      * @param  array|Traversable $var        variable to map | 
            
                                                                                                            
                            
            
                                    
            
            
                | 98 |  |  |      * @param  mixed             $mapKeyPath key to map; either a scalar or a | 
            
                                                                                                            
                            
            
                                    
            
            
                | 99 |  |  |      *     array interpreted as key path (i.e. ['foo', 'bar'] will return all | 
            
                                                                                                            
                            
            
                                    
            
            
                | 100 |  |  |      *     $item['foo']['bar'] values) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 101 |  |  |      * @return array                         mapped values | 
            
                                                                                                            
                            
            
                                    
            
            
                | 102 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 103 |  |  |     public function mapFilter($var, $mapKeyPath) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 104 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 105 |  |  |         if (!is_array($var) && (!is_object($var) || !is_a($var, 'Traversable'))) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 106 |  |  |             throw new Twig_Error_Runtime(sprintf( | 
            
                                                                                                            
                            
            
                                    
            
            
                | 107 |  |  |                 'The map filter only works with arrays or "Traversable", got "%s"', | 
            
                                                                                                            
                            
            
                                    
            
            
                | 108 |  |  |                 is_object($var) ? get_class($var) : gettype($var) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 109 |  |  |             )); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 110 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 111 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 112 |  |  |         $result = array(); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 113 |  |  |         foreach ($var as $key => $value) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 114 |  |  |             $mapValue = $this->getKeyOfVar($value, $mapKeyPath); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 115 |  |  |             $result[$key] = ($mapValue !== null) ? $mapValue : $value; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 116 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 117 |  |  |         return $result; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 118 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 119 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 120 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 121 |  |  |      * Sorts an array by one of its keys or a arbitrary deep sub-key | 
            
                                                                                                            
                            
            
                                    
            
            
                | 122 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 123 |  |  |      * This method is registered as the Twig `sort_by` filter. You can use this | 
            
                                                                                                            
                            
            
                                    
            
            
                | 124 |  |  |      * filter to e.g. sort the pages array by a arbitrary meta value. Calling | 
            
                                                                                                            
                            
            
                                    
            
            
                | 125 |  |  |      * `{{ pages|sort_by("meta:nav"|split(":")) }}` returns all pages sorted by | 
            
                                                                                                            
                            
            
                                    
            
            
                | 126 |  |  |      * the meta value `nav`. Please note the `"meta:nav"|split(":")` part of | 
            
                                                                                                            
                            
            
                                    
            
            
                | 127 |  |  |      * the example. The sorting algorithm will never assume equality of two | 
            
                                                                                                            
                            
            
                                    
            
            
                | 128 |  |  |      * values, it will then fall back to the original order. The result is | 
            
                                                                                                            
                            
            
                                    
            
            
                | 129 |  |  |      * always sorted in ascending order, apply Twigs `reverse` filter to | 
            
                                                                                                            
                            
            
                                    
            
            
                | 130 |  |  |      * achieve a descending order. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 131 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 132 |  |  |      * @param  array|Traversable $var         variable to sort | 
            
                                                                                                            
                            
            
                                    
            
            
                | 133 |  |  |      * @param  mixed             $sortKeyPath key to use for sorting; either | 
            
                                                                                                            
                            
            
                                    
            
            
                | 134 |  |  |      *     a scalar or a array interpreted as key path (i.e. ['foo', 'bar'] | 
            
                                                                                                            
                            
            
                                    
            
            
                | 135 |  |  |      *     will sort $var by $item['foo']['bar']) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 136 |  |  |      * @param  string            $fallback    specify what to do with items | 
            
                                                                                                            
                            
            
                                    
            
            
                | 137 |  |  |      *     which don't contain the specified sort key; use "bottom" (default) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 138 |  |  |      *     to move those items to the end of the sorted array, "top" to rank | 
            
                                                                                                            
                            
            
                                    
            
            
                | 139 |  |  |      *     them first, or "keep" to keep the original order of those items | 
            
                                                                                                            
                            
            
                                    
            
            
                | 140 |  |  |      * @return array                          sorted array | 
            
                                                                                                            
                            
            
                                    
            
            
                | 141 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 142 |  |  |     public function sortByFilter($var, $sortKeyPath, $fallback = 'bottom') | 
            
                                                                                                            
                            
            
                                    
            
            
                | 143 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 144 |  |  |         if (is_object($var) && is_a($var, 'Traversable')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 145 |  |  |             $var = iterator_to_array($var, true); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 146 |  |  |         } elseif (!is_array($var)) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 147 |  |  |             throw new Twig_Error_Runtime(sprintf( | 
            
                                                                                                            
                            
            
                                    
            
            
                | 148 |  |  |                 'The sort_by filter only works with arrays or "Traversable", got "%s"', | 
            
                                                                                                            
                            
            
                                    
            
            
                | 149 |  |  |                 is_object($var) ? get_class($var) : gettype($var) | 
            
                                                                                                            
                            
            
                                    
            
            
                | 150 |  |  |             )); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 151 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 152 |  |  |         if (($fallback !== 'top') && ($fallback !== 'bottom') && ($fallback !== 'keep')) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 153 |  |  |             throw new Twig_Error_Runtime('The sort_by filter only supports the "top", "bottom" and "keep" fallbacks'); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 154 |  |  |         } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 155 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 156 |  |  |         $twigExtension = $this; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 157 |  |  |         $varKeys = array_keys($var); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 158 |  |  |         uksort($var, function ($a, $b) use ($twigExtension, $var, $varKeys, $sortKeyPath, $fallback, &$removeItems) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 159 |  |  |             $aSortValue = $twigExtension->getKeyOfVar($var[$a], $sortKeyPath); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 160 |  |  |             $aSortValueNull = ($aSortValue === null); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 161 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 162 |  |  |             $bSortValue = $twigExtension->getKeyOfVar($var[$b], $sortKeyPath); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 163 |  |  |             $bSortValueNull = ($bSortValue === null); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 164 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 165 |  |  |             if ($aSortValueNull xor $bSortValueNull) { | 
                            
                    |  |  |  | 
                                                                                        
                                                                                     | 
            
                                                                                                            
                            
            
                                    
            
            
                | 166 |  |  |                 if ($fallback === 'top') { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 167 |  |  |                     return ($aSortValueNull - $bSortValueNull) * -1; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 168 |  |  |                 } elseif ($fallback === 'bottom') { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 169 |  |  |                     return ($aSortValueNull - $bSortValueNull); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 170 |  |  |                 } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 171 |  |  |             } elseif (!$aSortValueNull && !$bSortValueNull) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 172 |  |  |                 if ($aSortValue != $bSortValue) { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 173 |  |  |                     return ($aSortValue > $bSortValue) ? 1 : -1; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 174 |  |  |                 } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 175 |  |  |             } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 176 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 177 |  |  |             // never assume equality; fallback to original order | 
            
                                                                                                            
                            
            
                                    
            
            
                | 178 |  |  |             $aIndex = array_search($a, $varKeys); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 179 |  |  |             $bIndex = array_search($b, $varKeys); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 180 |  |  |             return ($aIndex > $bIndex) ? 1 : -1; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 181 |  |  |         }); | 
            
                                                                                                            
                            
            
                                    
            
            
                | 182 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 183 |  |  |         return $var; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 184 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 185 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 186 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 187 |  |  |      * Returns the value of a variable item specified by a scalar key or a | 
            
                                                                                                            
                            
            
                                    
            
            
                | 188 |  |  |      * arbitrary deep sub-key using a key path | 
            
                                                                                                            
                            
            
                                    
            
            
                | 189 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 190 |  |  |      * @param  array|Traversable|ArrayAccess|object $var     base variable | 
            
                                                                                                            
                            
            
                                    
            
            
                | 191 |  |  |      * @param  mixed                                $keyPath scalar key or a | 
            
                                                                                                            
                            
            
                                    
            
            
                | 192 |  |  |      *     array interpreted as key path (when passing e.g. ['foo', 'bar'], | 
            
                                                                                                            
                            
            
                                    
            
            
                | 193 |  |  |      *     the method will return $var['foo']['bar']) specifying the value | 
            
                                                                                                            
                            
            
                                    
            
            
                | 194 |  |  |      * @return mixed                                         the requested | 
            
                                                                                                            
                            
            
                                    
            
            
                | 195 |  |  |      *     value or NULL when the given key or key path didn't match | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 196 |  |  |      */ | 
            
                                                        
            
                                    
            
            
                | 197 |  |  |     public static function getKeyOfVar($var, $keyPath) | 
            
                                                        
            
                                    
            
            
                | 198 |  |  |     { | 
            
                                                        
            
                                    
            
            
                | 199 |  |  |         if (empty($keyPath)) { | 
            
                                                        
            
                                    
            
            
                | 200 |  |  |             return null; | 
            
                                                        
            
                                    
            
            
                | 201 |  |  |         } elseif (!is_array($keyPath)) { | 
            
                                                        
            
                                    
            
            
                | 202 |  |  |             $keyPath = array($keyPath); | 
            
                                                        
            
                                    
            
            
                | 203 |  |  |         } | 
            
                                                        
            
                                    
            
            
                | 204 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 205 |  |  |         foreach ($keyPath as $key) { | 
            
                                                        
            
                                    
            
            
                | 206 |  |  |             if (is_object($var)) { | 
            
                                                        
            
                                    
            
            
                | 207 |  |  |                 if (is_a($var, 'ArrayAccess')) { | 
                            
                    |  |  |  | 
                                                                                        
                                                                                     | 
            
                                                        
            
                                    
            
            
                | 208 |  |  |                     // use ArrayAccess, see below | 
            
                                                        
            
                                    
            
            
                | 209 |  |  |                 } elseif (is_a($var, 'Traversable')) { | 
            
                                                        
            
                                    
            
            
                | 210 |  |  |                     $var = iterator_to_array($var); | 
            
                                                        
            
                                    
            
            
                | 211 |  |  |                 } elseif (isset($var->{$key})) { | 
            
                                                        
            
                                    
            
            
                | 212 |  |  |                     $var = $var->{$key}; | 
            
                                                        
            
                                    
            
            
                | 213 |  |  |                     continue; | 
            
                                                        
            
                                    
            
            
                | 214 |  |  |                 } elseif (is_callable(array($var, 'get' . ucfirst($key)))) { | 
            
                                                        
            
                                    
            
            
                | 215 |  |  |                     try { | 
            
                                                        
            
                                    
            
            
                | 216 |  |  |                         $var = call_user_func(array($var, 'get' . ucfirst($key))); | 
            
                                                        
            
                                    
            
            
                | 217 |  |  |                         continue; | 
            
                                                        
            
                                    
            
            
                | 218 |  |  |                     } catch (BadMethodCallException $e) { | 
            
                                                        
            
                                    
            
            
                | 219 |  |  |                         return null; | 
            
                                                        
            
                                    
            
            
                | 220 |  |  |                     } | 
            
                                                        
            
                                    
            
            
                | 221 |  |  |                 } else { | 
            
                                                        
            
                                    
            
            
                | 222 |  |  |                     return null; | 
            
                                                        
            
                                    
            
            
                | 223 |  |  |                 } | 
            
                                                        
            
                                    
            
            
                | 224 |  |  |             } elseif (!is_array($var)) { | 
            
                                                        
            
                                    
            
            
                | 225 |  |  |                 return null; | 
            
                                                        
            
                                    
            
            
                | 226 |  |  |             } | 
            
                                                        
            
                                    
            
            
                | 227 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 228 |  |  |             if (isset($var[$key])) { | 
            
                                                        
            
                                    
            
            
                | 229 |  |  |                 $var = $var[$key]; | 
            
                                                        
            
                                    
            
            
                | 230 |  |  |                 continue; | 
            
                                                        
            
                                    
            
            
                | 231 |  |  |             } | 
            
                                                        
            
                                    
            
            
                | 232 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 233 |  |  |             return null; | 
            
                                                        
            
                                    
            
            
                | 234 |  |  |         } | 
            
                                                        
            
                                    
            
            
                | 235 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 236 |  |  |         return $var; | 
            
                                                        
            
                                    
            
            
                | 237 |  |  |     } | 
            
                                                        
            
                                    
            
            
                | 238 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 239 |  |  |  | 
            
                        
If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.