System.Text.RegularExpressions.RegexParser.Textto C# (CSharp) Method

        internal void Textto(int pos)
        {
            _currentPos = pos;
        }

 internal static string Unescape(string input)
 {
     for (int i = 0; i < input.Length; i++)
     {
         if (input[i] == '\\')
         {
             StringBuilder builder = new StringBuilder();
             RegexParser parser = new RegexParser(CultureInfo.InvariantCulture);
             parser.SetPattern(input);
             builder.Append(input, 0, i);
             do
             {
                 i++;
                 parser.Textto(i);
                 if (i < input.Length)
                 {
                     builder.Append(parser.ScanCharEscape());
                 }
                 i = parser.Textpos();
                 int startIndex = i;
                 while ((i < input.Length) && (input[i] != '\\'))
                 {
                     i++;
                 }
                 builder.Append(input, startIndex, i - startIndex);
             }
             while (i < input.Length);
             return builder.ToString();
         }
     }
     return input;
 }