roman_numbers

Description:

roman numbers

Library converts Arabic numbers into Roman and vice versa. It supports range
starting from zero (including) up to 5 billion (excluding).
Usage #
A simple usage example:
import 'package:roman_numbers/roman_numbers.dart';

main() {
var arabic = RomanNumbers.fromRoman('MMXXI');
print('MMXXI converted to arabic: $arabic');
assert(arabic == 2021);
var roman = RomanNumbers.toRoman(2021);
print('2021 converted to roman: $roman');
assert(roman == 'MMXXI');

//large numbers
arabic = RomanNumbers.fromRoman('M̿M̿M̿M̿D̿C̿C̿C̿L̿X̿X̿X̿V̿I̿I̿I̿D̅C̅C̅C̅L̅X̅X̅X̅V̅I̅I̅I̅DCCCLXXXVIII');
print('M̿M̿M̿M̿D̿C̿C̿C̿L̿X̿X̿X̿V̿I̿I̿I̿D̅C̅C̅C̅L̅X̅X̅X̅V̅I̅I̅I̅DCCCLXXXVIII converted to arabic: $arabic');
assert(arabic == 4888888888);

roman = RomanNumbers.toRoman(4732156498);
print('4732156498 converted to roman: $roman');
assert(roman == 'M̿M̿M̿M̿D̿C̿C̿X̿X̿X̿M̅M̅C̅L̅V̅I̅CDXCVIII');
}
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Details #
Implementation supports various unicode characters for conversion:

0: N, n
1: I, i, Ⅰ, ⅰ
2: Ⅱ, ⅱ
3: Ⅲ, ⅲ
4: Ⅳ, ⅳ
5: V, v, Ⅴ, ⅴ
6: Ⅵ, ⅵ, ↅ
7: Ⅶ, ⅶ
8: Ⅷ, ⅷ
9: Ⅸ, ⅸ
10: X, x, Ⅹ, ⅹ
11: Ⅺ, ⅺ
12: Ⅻ, ⅻ
50: L, l, Ⅼ, ⅼ, ↆ
100: C, c, Ⅽ, ⅽ
500: D, d, Ⅾ, ⅾ
1000: M, m, Ī, ī, Ⅿ, ⅿ, ↀ
5000: ↁ
10000: ↂ
50000: ↇ
100000: ↈ

Characters:

̅ (U+0304 COMBINING MACRON) and
̅ (U+0305 COMBINING OVERLINE) are used as thousands multiplier and
̿ (U+033F COMBINING DOUBLE OVERLINE) as millions multiplier.
E.g. V̅ is 5000, C̅ = 100000 or M̿ is one billion.

According to the Proposal to Add Additional Ancient Roman Characters to UCS
there are more characters and multipliers that were used, however they are not part of
the Unicode characters set.
Features and bugs #
Please file feature requests and bugs at the issue tracker.