From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Jeff King <peff@peff.net>
Cc: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 2/3] parse-options: make OPT_ARGUMENT() more useful
Date: Fri, 15 Mar 2019 14:24:50 +0100 (STD) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1903151421110.41@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20190315031553.GB28943@sigill.intra.peff.net>
[-- Attachment #1: Type: text/plain, Size: 2659 bytes --]
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
next prev parent reply other threads:[~2019-03-15 13:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-13 19:20 [PATCH 0/2] Allow difftool to be run outside of Git worktrees Johannes Schindelin via GitGitGadget
2019-03-13 19:20 ` [PATCH 2/2] difftool: allow running outside Git worktrees with --no-index Johannes Schindelin via GitGitGadget
2019-03-13 20:46 ` Jeff King
2019-03-14 12:16 ` Johannes Schindelin
2019-03-15 3:08 ` Jeff King
2019-03-13 19:20 ` [PATCH 1/2] difftool: remove obsolete (and misleading) comment Johannes Schindelin via GitGitGadget
2019-03-14 11:25 ` [PATCH v2 0/3] Allow difftool to be run outside of Git worktrees Johannes Schindelin via GitGitGadget
2019-03-14 11:25 ` [PATCH v2 1/3] difftool: remove obsolete (and misleading) comment Johannes Schindelin via GitGitGadget
2019-03-14 11:25 ` [PATCH v2 2/3] parse-options: make OPT_ARGUMENT() more useful Johannes Schindelin via GitGitGadget
2019-03-15 3:15 ` Jeff King
2019-03-15 13:24 ` Johannes Schindelin [this message]
2019-03-18 2:47 ` Junio C Hamano
2019-03-18 21:04 ` Jeff King
2019-03-19 0:25 ` Junio C Hamano
2019-03-14 11:25 ` [PATCH v2 3/3] difftool: allow running outside Git worktrees with --no-index Johannes Schindelin via GitGitGadget
2019-03-15 3:17 ` Jeff King
2019-03-15 13:20 ` Johannes Schindelin
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