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

        internal int TypeFromCode(char ch)
        {
            switch (ch)
            {
                case 'b':
                    return UseOptionE() ? RegexNode.ECMABoundary : RegexNode.Boundary;
                case 'B':
                    return UseOptionE() ? RegexNode.NonECMABoundary : RegexNode.Nonboundary;
                case 'A':
                    return RegexNode.Beginning;
                case 'G':
                    return RegexNode.Start;
                case 'Z':
                    return RegexNode.EndZ;
                case 'z':
                    return RegexNode.End;
                default:
                    return RegexNode.Nothing;
            }
        }