Consider custom parsers/converters/handler for types?

[RobThree]

I would love to be able to do:

public class Options
{
    [Option('o', "out", Required = true, HelpText = "Output file")]
    public string OutFile { get; set; }
    [Option('d', "duration", Required = false, Default = "1:00:00", HelpText = "Duration")]
    public TimeSpan Duration { get; set; }
    [Option('e', "endpoint", Required = true, HelpText = "IP Endpoint (<ip>:<port>)")]
    public IPEndPoint Endpoint { get; set; }
}

Where I can use types like TimeSpan and IPEndPoint or any other type. Ofcourse, we would need to be able to specify a parser/converter/handler/whatever that takes the value and converts it to the desired type. I imagine it be like:

public class Options
{
    [Option('o', "out", Required = true, HelpText = "Output file")]
    public string OutFile { get; set; }
    [Option('d', "duration", Required = false, Default = "1:00:00", HelpText = "Duration", Converter = typeof(MyTimeSpanConverter))]
    public TimeSpan Duration { get; set; }
    [Option('e', "endpoint", Required = true, HelpText = "IP Endpoint (<ip>:<port>)", Converter = typeof(MyIPEndpointConverter))]
    public IPEndPoint Endpoint { get; set; }
}

Next these 'converters' should implement something like an IConvert<T> that defines a method T Convert(string value) where they take a string (the commandline argument) and convert to the desired type. Another option would be to not use the attributes but be able to specify handlers like:

Parser.Default
    .Register<TimeSpan, MyTimeSpanConverter>()
    .Register<IPEndPoint, MyIPEndPointConverter>()
    .ParseArguments<Options>(args)
    ....

Would that be something that you would consider? (Maybe not exactly following the idea given above, but the broader idea of being able to handle custom types).

[znakeeye]

Some ideas to solve this:

• Add support for TypeConverterAttribute
• Add support for IConvertible
• Call explicit/implicit cast operator using Expression.Convert