System.CSharpHelpers.IsValidTypeNameOrIdentifier C# (CSharp) Method

        internal static bool IsValidTypeNameOrIdentifier(string value, bool isTypeName)
        {
            bool nextMustBeStartChar = true;

            if (value.Length == 0)
                return false;

            // each char must be Lu, Ll, Lt, Lm, Lo, Nd, Mn, Mc, Pc
            //
            for (int i = 0; i < value.Length; i++)
            {
                char ch = value[i];
                UnicodeCategory uc = CharUnicodeInfo.GetUnicodeCategory(ch);
                switch (uc)
                {
                    case UnicodeCategory.UppercaseLetter:        // Lu
                    case UnicodeCategory.LowercaseLetter:        // Ll
                    case UnicodeCategory.TitlecaseLetter:        // Lt
                    case UnicodeCategory.ModifierLetter:         // Lm
                    case UnicodeCategory.LetterNumber:           // Lm
                    case UnicodeCategory.OtherLetter:            // Lo
                        nextMustBeStartChar = false;
                        break;

                    case UnicodeCategory.NonSpacingMark:         // Mn
                    case UnicodeCategory.SpacingCombiningMark:   // Mc
                    case UnicodeCategory.ConnectorPunctuation:   // Pc
                    case UnicodeCategory.DecimalDigitNumber:     // Nd
                        // Underscore is a valid starting character, even though it is a ConnectorPunctuation.
                        if (nextMustBeStartChar && ch != '_')
                            return false;

                        nextMustBeStartChar = false;
                        break;
                    default:
                        // We only check the special Type chars for type names.
                        if (isTypeName && IsSpecialTypeChar(ch, ref nextMustBeStartChar))
                        {
                            break;
                        }

                        return false;
                }
            }

            return true;
        }