XP Subcommand / Options / Arguments parsing

Command.cs

using System;
using System.Collections.Generic;

interface Command
{
    int Run(Dictionary<string, string> options, IList<string> arguments);
}

run.cs

using System;
using System.Collections.Generic;

class run : Command
{

    public int Run(Dictionary<string, string> options, IList<string> arguments)
    {
        Console.Write("run(");
        foreach (var pair in options)
        {
            Console.Write("{0}=\"{1}\" ", pair.Key, pair.Value);
        }
        Console.WriteLine("arguments=[{0}])", String.Join(", ", arguments));

        return 0;
    }
}

xp.cs

using System;
using System.IO;
using System.Reflection;
using System.Collections.Generic;

class xp
{
    private static Dictionary<string, string> subcommands = new Dictionary<string, string>()
    {
        { "-e", "eval" },
        { "-v", "version" },
        { "-w", "write" },
        { "-d", "dump" }
    };

    public static int Main(string[] args)
    {
        var offset = 0;
        var subcommand = "run";
        var options = new Dictionary<string, string>()
        {
            { "include_path", "" }
        };

        for (var i = 0; i < args.Length; i++)
        {
            if ("-cp" == args[i])
            {
                options["include_path"] += ";" + args[++i];
            }
            else if (subcommands.ContainsKey(args[i]))
            {
                subcommand = subcommands[args[i]];
                offset = ++i;
                break;
            }
            else
            {
                subcommand = args[i];
                offset = ++i;
                break;
            }
        }

        try
        {
            var command = Assembly.LoadFrom(subcommand + ".dll").GetType(subcommand);
            var exit = command.GetMethod("Run").Invoke(Activator.CreateInstance(command, null), new object[]
            {
                options,
                new ArraySegment<string>(args, offset, args.Length - offset)
            });
            return exit is int ? (int)exit : 0x00;
        }
        catch (FileNotFoundException)
        {
            Console.Error.WriteLine("*** No such subcommand `{0}'", subcommand);
            return 0xff;
        }
    }
}

See xp-framework/rfc#303