How to implement custom command line & execution

Question

I\'m trying to build a custom commandline for my app, i have several basic commands, and i simply use bunch of \"if\" statements to check what the command is. currently it looks

Answer 1

You could stuff all commands into a Dictionary<string, someDelegate>; if you can live with all commands having the same return type.

I have used string and set up a few commands.

I make use of the params keyword to avoid the ugly new object[] on each call.

You still need to cast the arguments, unless you can make them all one type. (Which may actually be not such a bad idea, as they all come from an input string..)

Here is an example:

public delegate string cmdDel(params object[] args);

Dictionary<string,  cmdDel> cmd = new Dictionary<string,  cmdDel>();

Add a few functions:

cmd.Add("clear", cmd_clear);
cmd.Add("exit", cmd_exit);
cmd.Add("add", cmd_add);
cmd.Add("log", cmd_log);

With these bodies:

public string cmd_clear(params object[] args)
{
    return "cleared";
}

public string cmd_exit(params object[] args)
{
    return "exit";
}

public string cmd_add(params object[] args)
{
    return ((int)args[0] + (int)args[1]).ToString();
}

public string cmd_log(params object[] args)
{
    StringBuilder log = new StringBuilder();
    foreach (object a in args) log.Append(a.ToString() + " ");
    return log.ToString(); 
}

And test:

Console.WriteLine(cmd["clear"]());
Console.WriteLine(cmd["add"]( 23, 42));
Console.WriteLine(cmd["log"]( 23, "+" + 42, "=", cmd["add"]( 23, 42) ));
Console.WriteLine(cmd["exit"]());

cleared

65

23 + 42 = 65

exit

Of course you still need to use (at least) as many lines for setup as you have commands. And also need to do a similar amount of error checking.

But the command processing part can get pretty simple.