YuriyGuts.RegexBuilder.RegexNodeCharacterSet.ToRegexPattern C# (CSharp) Method

        public override string ToRegexPattern()
        {
            string characterSetPattern;
            if (UseCharacterCodes)
            {
                StringBuilder patternBuilder = new StringBuilder();
                foreach (char c in characters)
                {
                    patternBuilder.AppendFormat(CultureInfo.InvariantCulture, "\\u{0:x4}", (int)c);
                }
                characterSetPattern = patternBuilder.ToString();
            }
            else
            {
                characterSetPattern = characterListExpression;
            }

            string result = string.Format(CultureInfo.InvariantCulture, (IsNegative ? "[^{0}]" : "[{0}]"), characterSetPattern);
            if (HasQuantifier)
            {
                result += Quantifier.ToRegexPattern();
            }

            return result;
        }