[TUHS] getopt (was Re: Any Good dmr Anecdotes?
Bakul Shah
bakul at bitblocks.com
Wed Jul 11 13:34:58 AEST 2018
On Tue, 10 Jul 2018 18:31:27 -0700 Larry McVoy <lm at 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.
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