Boo.Lang.Parser.PrimitiveParser.ParseIntegerLiteralExpression C# (CSharp) Method

        public static IntegerLiteralExpression ParseIntegerLiteralExpression(antlr.IToken token, string s, bool asLong)
        {
            const string HEX_PREFIX = "0x";

            NumberStyles style = NumberStyles.Integer | NumberStyles.AllowExponent;
            int hex_start = s.IndexOf(HEX_PREFIX);
            bool negative = false;

            if (hex_start >= 0)
            {
                if (s.StartsWith("-"))
                {
                    negative = true;
                }
                s = s.Substring(hex_start + HEX_PREFIX.Length);
                style = NumberStyles.HexNumber;
            }

            long value = long.Parse(s, style, CultureInfo.InvariantCulture);
            if (negative) //negative hex number
            {
                value *= -1;
            }
            return new IntegerLiteralExpression(SourceLocationFactory.ToLexicalInfo(token), value, asLong || (value > int.MaxValue || value < int.MinValue));
        }