Validate that this argument works. By default, all arguments are valid.
public function validateArgument($arg) {
// By using % in URLs, arguments could be validated twice; this eases
// that pain.
if (isset($this->argument_validated)) {
return $this->argument_validated;
}
if ($this
->is_exception($arg)) {
return $this->argument_validated = TRUE;
}
$plugin = $this
->get_plugin('argument_validator');
return $this->argument_validated = $plugin
->validate_argument($arg);
}