toTomanString function
Implementation
String toTomanString(String s, {bool fromRial = false}) {
s = digitToEnglish(s);
if (int.tryParse(s) == null || int.parse(s).isNegative) {
throw Exception('$s is invalid.');
}
if (fromRial) s = s.substring(0, s.length - 1);
s = digitToFarsiString(s);
return '$s تومان';
}