Why D Needs Attributes (Was: Command-line arguments)

[superdan]

Nick Sabalausky Wrote:

> "Nick Sabalausky" <a at a.a> wrote in message 
> news:g4k93l$1mh$1 at digitalmars.com...
> > "Jarrett Billingsley" <kb3ctd2 at yahoo.com> wrote in message 
> > news:g4ju5s$2dh0$1 at digitalmars.com...
> >> "Matt" <no-one at none.nowhere.com> wrote in message
> >> news:g4jqum$269v$1 at digitalmars.com...
> >>> Is there an established library in D for handling command-line 
> >>> arguments?
> >>>
> >>> In particular:
> >>> - handling differences between Windows and UNIX shells (i.e. wildcard
> >>> expansion)
> >>> - handling equivalent options such as "-n 10" === --count=10
> >>> - handling combination of multiple flags, e.g. "-lcf" == "-l -f -c"
> >>>
> >>> Thanks
> >>>
> >>> Matt
> >>
> >> I don't believe there is an argument parser in either Phobos 1 or Phobos 
> >> 2.
> >> However, there is one in Tango.
> >>
> >
> > Command-line parsing is one of the big reasons I really wish D had C#/Java 
> > style attributes. I came across this one particular C# command-line parser 
> > (written by a Peter Hallam) a few years ago and absolutely fell in love 
> > with it, and by extention, attributes. (I'd link to it, but it was on 
> > GotDotNet, which MS replaced with something else and didn't move this 
> > particular program over. So I'm attaching the lastest version I have (only 
> > about 11k), even though there are newer versions...somewhere.)
> >
> > Just check out how awesomely simple it makes this sample case:
> >
> > BEGIN CODE
> > class WCArguments
> > {
> >    public bool lines;
> >    public bool words;
> >    public bool chars;
> > 
> > [Utilities.DefaultCommandLineArgument(Utilities.CommandLineArgumentType.MultipleUnique)]
> >    public string[] files;
> >
> > 
> > [Utilities.CommandLineArgument(Utilities.CommandLineArgumentType.AtMostOnce, 
> > ShortName = "num")]
> >    public int number;
> >    public string[] junk;
> > }
> >
> > class WC
> > {
> >    static void Main(string[] args)
> >    {
> >        WCArguments parsedArgs = new WCArguments();
> >        if (!Utilities.Utility.ParseCommandLineArguments(args, parsedArgs))
> >        {
> >            // error encountered in arguments. Display usage message
> > 
> > System.Console.Write(Utilities.Utility.CommandLineArgumentsUsage(typeof(WCArguments)));
> >        }
> >        else
> >        {
> >            // insert application code here
> >        }
> >    }
> > }
> > END CODE
> >
> > The WCArguments class is itself the very definition of the program's 
> > command-line arguments. And attributes can be used to specify things like 
> > "DefaultCommandLineArgument", "MultipleUnique", "AtMostOnce", "ShortName", 
> > "Required", etc. Later versions include automatically-generated help 
> > screens. And the command-line syntax is the same 
> > ultra-clean-consistent-and-unambiguous commandline syntax that MS's 
> > command-line .NET tools use.
> >
> > D2 could probably come close to this with its compile-time reflection, but 
> > I don't think there'd be a comparably simple way to specify the things 
> > that this uses attributes for.
> >
> 
> I just took a look at Phobos2's getopt. It's impressively code to this in 
> functionality. But I still think this is much cleaner and more DRY 
> ("drier"?)
> 
> 

in the words of the annoying chick in friends: oh....... my....... god! how could that dung be better than this?

void main(string[] args) 
{
    bool lines = true, words = true, chars = true;
    string[] files;
    int number;

    getopt(args,
        "lines", &lines,
        "words", &words,
        "lines", &lines,
        "files", &files,
        "num", &number);
    ........
}

this does everything that does /without/ adding a new class and redundant shit in square brackets. the fact that there could be multiple files is inferred from the type string[]. no new class, no attributes, no mess. shit man that c# stuff really blows. awesomely blows if you wish. how can anyone like that shit. to say nothing about the no-good generated help string that always is too short and uninformative to help shit. 

p.s. look! i wrote an entire post and no fuck! fuck me but this is weird. oops i fucked up again. :)