private function compileCondition(Condition $criteria = null)
{
if (null === $criteria) {
return null;
}
$operator = $criteria->getOperator();
if ('regex' === $operator) {
$operator = 'regexp';
}
$segments = [$this->processValue($criteria->getLeft(), $criteria->shouldEscapeLeft()), $operator, $this->processValue($criteria->getRight(), $criteria->shouldEscapeRight())];
return implode(' ', $segments);
}