toSingular function
Return singular form of plural.
Implementation
String toSingular(String plural) {
final RegExp isAbbr = RegExp(r'[A-Z0-9]$');
if (isAbbr.hasMatch(plural)) return plural;
String singular = plural;
for (final RegExp re in _singularRules.keys) {
if (re.hasMatch(plural)) {
singular = plural.replaceFirstMapped(re, _singularRules[re]!);
break;
}
}
return singular;
}