code: protected static function getNextToken(array &$tokens, $index, array $excludeTokens = [])
      {
          $tokenCount = count($tokens);
          while ($index < $tokenCount && isset($tokens[$index+1])
          && self::shouldSkip($tokens[$index + 1], $excludeTokens)) {
              $index++;
          }
  
          if (! isset($tokens[$index+1])) {
              return false;
          }
  
          return is_array($tokens[$index+1]) ? $tokens[$index+1][0] : $tokens[$index+1];
      }
docs: Finds the next token in token array after a given index.
  @param array $tokens Token array to lookup
  @param int $index Position to start lookup at
  @param array $excludeTokens Excluded tokens list
  
  @return int|string|false The next match if found, or false. Token is guaranteed to be a scalar if a match is found.