HTMLPurifier_ElementDef::mergeIn PHP Method

    public function mergeIn($def)
    {
        // later keys takes precedence
        foreach ($def->attr as $k => $v) {
            if ($k === 0) {
                // merge in the includes
                // sorry, no way to override an include
                foreach ($v as $v2) {
                    $this->attr[0][] = $v2;
                }
                continue;
            }
            if ($v === false) {
                if (isset($this->attr[$k])) {
                    unset($this->attr[$k]);
                }
                continue;
            }
            $this->attr[$k] = $v;
        }
        $this->_mergeAssocArray($this->excludes, $def->excludes);
        $this->attr_transform_pre = array_merge($this->attr_transform_pre, $def->attr_transform_pre);
        $this->attr_transform_post = array_merge($this->attr_transform_post, $def->attr_transform_post);
        if (!empty($def->content_model)) {
            $this->content_model = str_replace("#SUPER", $this->content_model, $def->content_model);
            $this->child = false;
        }
        if (!empty($def->content_model_type)) {
            $this->content_model_type = $def->content_model_type;
            $this->child = false;
        }
        if (!is_null($def->child)) {
            $this->child = $def->child;
        }
        if (!is_null($def->formatting)) {
            $this->formatting = $def->formatting;
        }
        if ($def->descendants_are_inline) {
            $this->descendants_are_inline = $def->descendants_are_inline;
        }
    }

 function test_mergeIn()
 {
     $def1 = new HTMLPurifier_ElementDef();
     $def2 = new HTMLPurifier_ElementDef();
     $def3 = new HTMLPurifier_ElementDef();
     $old = 1;
     $new = 2;
     $overloaded_old = 3;
     $overloaded_new = 4;
     $removed = 5;
     $def1->standalone = true;
     $def1->attr = array(0 => array('old-include'), 'old-attr' => $old, 'overloaded-attr' => $overloaded_old, 'removed-attr' => $removed);
     $def1->attr_transform_pre = $def1->attr_transform_post = array('old-transform' => $old, 'overloaded-transform' => $overloaded_old, 'removed-transform' => $removed);
     $def1->child = $overloaded_old;
     $def1->content_model = 'old';
     $def1->content_model_type = $overloaded_old;
     $def1->descendants_are_inline = false;
     $def1->excludes = array('old' => true, 'removed-old' => true);
     $def2->standalone = false;
     $def2->attr = array(0 => array('new-include'), 'new-attr' => $new, 'overloaded-attr' => $overloaded_new, 'removed-attr' => false);
     $def2->attr_transform_pre = $def2->attr_transform_post = array('new-transform' => $new, 'overloaded-transform' => $overloaded_new, 'removed-transform' => false);
     $def2->child = $new;
     $def2->content_model = '#SUPER | new';
     $def2->content_model_type = $overloaded_new;
     $def2->descendants_are_inline = true;
     $def2->excludes = array('new' => true, 'removed-old' => false);
     $def1->mergeIn($def2);
     $def1->mergeIn($def3);
     // empty, has no effect
     $this->assertIdentical($def1->standalone, true);
     $this->assertIdentical($def1->attr, array(0 => array('old-include', 'new-include'), 'old-attr' => $old, 'overloaded-attr' => $overloaded_new, 'new-attr' => $new));
     $this->assertIdentical($def1->attr_transform_pre, $def1->attr_transform_post);
     $this->assertIdentical($def1->attr_transform_pre, array('old-transform' => $old, 'overloaded-transform' => $overloaded_new, 'new-transform' => $new));
     $this->assertIdentical($def1->child, $new);
     $this->assertIdentical($def1->content_model, 'old | new');
     $this->assertIdentical($def1->content_model_type, $overloaded_new);
     $this->assertIdentical($def1->descendants_are_inline, true);
     $this->assertIdentical($def1->excludes, array('old' => true, 'new' => true));
 }