[TUHS] getopt (was Re: Any Good dmr Anecdotes?

[Bakul Shah <bakul@bitblocks.com>]

On Tue, 10 Jul 2018 18:31:27 -0700 Larry McVoy <lm@mcvoy.com> wrote:
Larry McVoy writes:
> On Wed, Jul 11, 2018 at 10:20:50AM +1000, Noel Hunt wrote:
> > I'm surprised why anyone would bother with these routines
> > anymore, given the startling simplicity of Plan9's arg(3).
> > One stands in awe of such simplicity. I believe it was
> > William Cheswick who designed it, but I may be wrong.

plan9 arg macros are indeed very nice.

> It's nice but I like long opts.  The getopt in BK (and now in L)
> looks like this and produces its own help (which does miss the 
> short opts, my bad, I could fix that).  Look at the default in
> the switch:
>
> 	string	c;
> 	string	lopts[] = {
> 		"bigy:",
> 		"date-split",
    ...
> 		"title:",
> 		"ysize:",
> 	};
>
> 	while (c = getopt(av, "fj:", lopts)) {
> 		switch (c) {
> 		    case "bigy": bigy = (int)optarg; break;
> 		    case "date-split": dates = 1; break;
    ...
> 		    case "title": title = optarg; break;
> 		    case "thumbnails": thumbnails = 1; break;
> 		    case "ysize": ysize = (int)optarg; break;
> 		    default: 
> 			printf("Usage: photos.l");

[You can also do a switch on string in Go.]

Having to write the same strings twice is a pain. May be even
three times, if you add usage()!

I don't much like long options as they tend to proliferate.
-- Your typical engineer doesn't like to make hard choices so
indecisions turn into options!

If there have to be long options, I want to be able to
abbreviate them and I want word completion and context
sensitive help as invariably long options end up having
complex semantics.