Hi Junio,
On Fri, 22 Jan 2021, Junio C Hamano wrote:
> "Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx>
> writes:
>
> > + i = strlen(range);
> > + c = i > 2 ? range[--i] : 0;
> > + if (c == '!')
> > + i--; /* might be ...^! */
> > + else if (isdigit(c)) {
> > + /* handle ...^-<n> */
> > + while (i > 2 && isdigit(range[--i]))
> > + ; /* keep trimming trailing digits */
> > + if (i < 2 || range[i--] != '-')
> > + return 0;
> > + } else
> > + return 0;
> > +
> > + /* Before the `!` or the `-<n>`, we expect `<rev>^` */
> > + return i > 0 && range[i] == '^';
>
> This is still way too complex for my liking, but at least I cannot
> immediately spot a glaring off-by-one like the previous round ;-)
Maybe I am too stuck with the idea of avoiding regular expressions after
that StackOverflow incident... Maybe
static regex_t *regex;
if (strstr(range, ".."))
return 1;
if (!regex) {
regex = xmalloc(sizeof(*regex));
if (regcomp(regex, "\\^(!|-[0-9]*)$", REG_EXTENDED))
BUG("could not compile regex");
}
return !regexec(regex, range, 0, NULL, 0);
is more readable, and acceptable in this context?
> This is a tangent ([*1*]), but we often equate an omission to
> implicitly specified HEAD; e.g. "git log @{u}.." is what we did
> since we started building on top of our upstream. I wonder if it
> makes sense to allow similar short-hand so that ^! alone would mean
> HEAD^!, ^@ alone would mean HEAD^@, and so on.
I don't know. On one hand, it would make things more consistent. On the
other hand, it would be relatively hard to explain, I think. And we
already have the shortcut `@!^`, which is hard enough to explain as it is.
Ciao,
Dscho
