public function buildProximityMatch($operator, $operands, &$params)
{
if (!isset($operands[0], $operands[1], $operands[2])) {
throw new InvalidParamException("Operator '{$operator}' requires three operands.");
}
list($column, $value, $proximity) = $operands;
return $this->buildMatchColumn($column) . ' ' . $this->buildMatchValue($value, $params) . '~' . (int) $proximity;
}