Prepares parameters
array $parameters:
array
private function prepareParameters($parameters) {
$filtered = array();
foreach ($parameters as $key => $value) {
if (is_array($value)) {
$value = $this
->prepareParameters($value);
}
elseif ($value instanceof Reference) {
$value = '@' . $value;
}
$filtered[$key] = $value;
}
return $this
->escape($filtered);
}