Mono.CSharp.Driver.IsExternAliasValid C# (CSharp) Method

		static bool IsExternAliasValid (string identifier)
		{
			if (identifier.Length == 0)
				return false;
			if (identifier [0] != '_' && !Char.IsLetter (identifier [0]))
				return false;

			for (int i = 1; i < identifier.Length; i++) {
				char c = identifier [i];
				if (Char.IsLetter (c) || Char.IsDigit (c))
					continue;

				UnicodeCategory category = Char.GetUnicodeCategory (c);
				if (category != UnicodeCategory.Format || category != UnicodeCategory.NonSpacingMark ||
						category != UnicodeCategory.SpacingCombiningMark ||
						category != UnicodeCategory.ConnectorPunctuation)
					return false;
			}
			
			return true;
		}