[TUHS] Systematic approach to command-line interfaces [ meta issues ]

Jon Steinhart jon at fourwinds.com
Sun Aug 1 07:32:06 AEST 2021

Richard Salz writes:
> On Sat, Jul 31, 2021 at 3:21 PM Jon Steinhart <jon at fourwinds.com> wrote:
> > opinion, it doesn't add value to do something that's already been done
> > but differently; it detracts from value because now there's yet another
> > competing way to do something.
> >
> You mean like not using getopt and rolling your own?  Shrug.
> while ((i = getopt(argc, argv, "xxxxx:xxxx")) != -1)
>    switch (i) {
>    case ....
>   }
> argc -= optind;
> argv += optind;
> So I never got getopt().  One of my rules is that I don't use a library
> > in cases where the number of lines of gunk that that it takes to use a
> > library function is >= the number of lines to just write it myself.
> I don't know, what lines in the above are extra beyond what you write?  The
> last two if being generous I suppose.

Well, in my opinion that's not really an accurate representation of using getopt.

I would of course write the #include line, and the table of options, which would
end up being >= the number of lines that it takes me to do this...

	while (--argc > 0) {
		if (*(++argv)[0] == '-') {
			for (p = *argv + 1; *p != '\0'; p++) {
				switch (*p) {

Even if it took a few more lines to do it my way, I'm a believer that good coding
style keeps "meatspace locality of reference" in mind.  As programmers, we put in
a lot of effort to ensure locality of reference for computers, but then completely
toss it for people who aren't as good as it.  So given a choice of a few lines of
code versus having to look something up somewhere else, I choose the few lines of

Being a geezer, I have lots of code lying around from which I can extract working
fragments such as the one above.  Writing those few lines of code provides insulation
from supply-side attack vectors bugs in libraries, versioning issues, having to load
debug libraries, and so on.

I realize that this isn't a huge deal by itself; it's a philosophical point.  When
I strace any random program that I didn't write I'm astonished by the amount of
library loading that takes place.  So any issues are multiplied by n.

Don't get me wrong; I use plenty of libraries.  But I tend to use those for stuff
that is so common that there is a benefit from shared libraries (or at least there
was before everything got containerized) and for libraries that do actual hard stuff.
But I don't use libraries for small snippets of code that I could easily write
myself yielding better code clarity for others reading my code.


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