function render()
{
// Validate defaultParam's value.
$def = $this->getDefaultParam();
if (!empty($def)) {
if (!$this->props->defines($def)) {
throw new ComponentException($this, "Invalid value for <kbd>defaultParam</kbd> on <b><{$this->props->macro}></b>; parameter <kbd>{$def}</kbd> does not exist");
}
// Move children to default parameter.
if ($this->hasChildren()) {
$type = $this->props->getTypeOf($def);
if ($type != type::content && $type != type::metadata) {
throw new ComponentException($this, sprintf("The macro's default parameter <kbd>{$def}</kbd> can't hold content because its type is <kbd>%s</kbd>.", type::getNameOf($type)));
}
$param = new Metadata($this->context, ucfirst($def), $type);
$this->props->set($def, $param);
$param->attachTo($this);
$param->setChildren($this->getChildren());
}
} elseif ($this->hasChildren()) {
throw new ComponentException($this, 'You may not specify content for this tag because it has no default property');
}
parent::render();
}
