1000, 'D' => 500, 'C' => 100, 'L' => 50, 'X' => 10, 'V' => 5, 'I' => 1, ]; /** * Recursively calculate the arabic value of a roman numeral. * * @param mixed[] $roman */ private static function calculateArabic(array $roman, int &$sum = 0, int $subtract = 0): int { $numeral = array_shift($roman); if (!isset(self::ROMAN_LOOKUP[$numeral])) { throw new Exception('Invalid character detected'); } $arabic = self::ROMAN_LOOKUP[$numeral]; if (count($roman) > 0 && isset(self::ROMAN_LOOKUP[$roman[0]]) && $arabic < self::ROMAN_LOOKUP[$roman[0]]) { $subtract += $arabic; } else { $sum += ($arabic - $subtract); $subtract = 0; } if (count($roman) > 0) { self::calculateArabic($roman, $sum, $subtract); } return $sum; } /** * ARABIC. * * Converts a Roman numeral to an Arabic numeral. * * Excel Function: * ARABIC(text) * * @param string|string[] $roman Should be a string, or can be an array of strings * * @return array|int|string the arabic numberal contrived from the roman numeral * If an array of numbers is passed as the argument, then the returned result will also be an array * with the same dimensions */ public static function evaluate(mixed $roman): array|int|string { if (is_array($roman)) { return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $roman); } // An empty string should return 0 $roman = substr(trim(strtoupper((string) $roman)), 0, 255); if ($roman === '') { return 0; } // Convert the roman numeral to an arabic number $negativeNumber = $roman[0] === '-'; if ($negativeNumber) { $roman = trim(substr($roman, 1)); if ($roman === '') { return ExcelError::NAN(); } } try { $arabic = self::calculateArabic(mb_str_split($roman, 1, 'UTF-8')); } catch (Exception) { return ExcelError::VALUE(); // Invalid character detected } if ($negativeNumber) { $arabic *= -1; // The number should be negative } return $arabic; } }