code: public static function SEARCHSENSITIVE($needle, $haystack, $offset = 1)
      {
          $needle = Functions::flattenSingleValue($needle);
          $haystack = Functions::flattenSingleValue($haystack);
          $offset = Functions::flattenSingleValue($offset);
  
          if (!is_bool($needle)) {
              if (is_bool($haystack)) {
                  $haystack = ($haystack) ? Calculation::getTRUE() : Calculation::getFALSE();
              }
  
              if (($offset > 0) && (StringHelper::countCharacters($haystack) > $offset)) {
                  if (StringHelper::countCharacters($needle) == 0) {
                      return $offset;
                  }
  
                  $pos = mb_strpos($haystack, $needle, --$offset, 'UTF-8');
                  if ($pos !== false) {
                      return ++$pos;
                  }
              }
          }
  
          return Functions::VALUE();
      }
docs: SEARCHSENSITIVE.
  
  @param string $needle The string to look for
  @param string $haystack The string in which to look
  @param int $offset Offset within $haystack
  
  @return string