Hi Peff, On Thu, 14 Mar 2019, Jeff King wrote: > On Thu, Mar 14, 2019 at 04:25:04AM -0700, Johannes Schindelin via GitGitGadget wrote: > > > diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt > > index 2b036d7838..2e2e7c10c6 100644 > > --- a/Documentation/technical/api-parse-options.txt > > +++ b/Documentation/technical/api-parse-options.txt > > @@ -198,8 +198,10 @@ There are some macros to easily define options: > > The filename will be prefixed by passing the filename along with > > the prefix argument of `parse_options()` to `prefix_filename()`. > > > > -`OPT_ARGUMENT(long, description)`:: > > +`OPT_ARGUMENT(long, &int_var, description)`:: > > Introduce a long-option argument that will be kept in `argv[]`. > > + If this option was seen, `int_var` will be set to one (except > > + if a `NULL` pointer was passed). > > So this effectively makes it into a "bool" that we keep. Almost. It is only a "seen" in the sense that you cannot re-set it to `false`. But yeah, the difference is subtle. > I think that's fine. It always uses NOARG, so it is not like we would > ever need to see "we got --foo, and this is the argument it had". Yep, I checked that. > I did wonder if it was possible for "--no-foo" to trigger this (leaving > the caller who looks at the int unsure if they saw "--foo" or > "--no-foo"), but it seems that the parse-options code checks for > OPTION_ARGUMENT before it ever looks at negation. I checked that, too. > Curiously, it also checks it before doing the usual prefix-matching > magic. So you could otherwise say "--no-inde", but OPT_ARGUMENT() will > not allow it. I think that's probably sane and not worth thinking > further about, but it is an interesting quirk that a user could possibly > run into. I missed that... ¯\_(ツ)_/¯ > > diff --git a/parse-options.c b/parse-options.c > > index cec74522e5..1d57802da0 100644 > > --- a/parse-options.c > > +++ b/parse-options.c > > @@ -286,6 +286,8 @@ static enum parse_opt_result parse_long_opt( > > optname(options, flags)); > > if (*rest) > > continue; > > + if (options->value) > > + *(int *)options->value = options->defval; > > Cute. You could actually assign any defval you like, though of course > the convenient OPT_ARGUMENT() macro just always uses 1. > > I wondered if you might need another cast for defval itself, but it's an > intptr_t (so it's the types that use it as a string that need to cast to > "const char *"). Exactly. > This looks very clean overall, and I agree it's much nicer than the > alternatives for your use case. Thank you! 😊 Dscho
