From: Junio C Hamano <gitster@pobox.com>
To: Pranit Bauva <pranit.bauva@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] api-parse-options.txt: document OPT_CMDMODE()
Date: Thu, 24 Mar 2016 09:07:09 -0700 [thread overview]
Message-ID: <xmqqtwjvamhe.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <01020153a7e08100-cf66fc9f-7293-4d8c-98c6-f322721c741f-000000@eu-west-1.amazonses.com> (Pranit Bauva's message of "Thu, 24 Mar 2016 09:07:01 +0000")
Pranit Bauva <pranit.bauva@gmail.com> writes:
> OPT_CMDMODE() was introduced in the release of 1.8.5 which makes the use
> of subcommands in the form of arguments a lot cleaner and easier.
> ---
Sign-off?
> Documentation/technical/api-parse-options.txt | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
> index 5f0757d..8130d26 100644
> --- a/Documentation/technical/api-parse-options.txt
> +++ b/Documentation/technical/api-parse-options.txt
> @@ -231,6 +231,12 @@ There are some macros to easily define options:
> pass the command-line option, which can be specified multiple times,
> to another command.
>
> +`OPT_CMDMODE(short, long, &int_var, description, enum_val)`::
> + Introduce an option for subcommands. It is useful when you want to use
> + the command with a particular sub command only and ignore other sub
> + commands it has. It will set `int_var` to enum_val if the argument is
> + invoked.
> +
Sorry, but I do not get what "when you want to... ignore other sub
command it has" wants to say.
CMDMODE is a mechanism to actively notice when multiple "operation
mode" options that specify mutually incompatible operation modes are
given and error out without the user of parse_options() to implement
that mutual exclusion herself. That is, if you have 'add', 'remove'
and 'edit' operation modes, with OPT_BOOL(), you would have to say:
options[] = {
OPT_BOOL('a', "add", &add, ...),
OPT_BOOL('r', "remove", &remove, ...),
OPT_BOOL('e', "edit", &edit, ...),
...
};
parse_options(ac, av, prefix, options, ...);
if (!!add + !!remove + !!edit > 1)
die("at most one add/remove/edit can be used at a time");
if (add)
do_add();
if (remove)
do_remove();
if (edit)
do_edit();
but with CMDMODE, you can do:
options[] = {
OPT_BOOL('a', "add", &mode, ...),
OPT_BOOL('r', "remove", &mode, ...),
OPT_BOOL('e', "edit", &mode, ...),
...
};
parse_options(ac, av, prefix, options, ...);
switch (mode) {
case 'a': do_add(); break;
case 'r': do_remove(); break;
case 'e': do_edit(); break;
...
}
and parse_options notices that "mode" is shared across these three
options, and implements the mutual-exclusion itself.
next prev parent reply other threads:[~2016-03-24 16:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 9:07 [PATCH] api-parse-options.txt: document OPT_CMDMODE() Pranit Bauva
2016-03-24 16:07 ` Junio C Hamano [this message]
2016-03-24 16:55 ` Pranit Bauva
2016-03-24 17:16 ` Junio C Hamano
2016-03-24 18:04 ` Pranit Bauva
2016-03-25 18:58 ` [PATCH v2] " Pranit Bauva
2016-03-25 19:08 ` Pranit Bauva
2016-03-25 21:24 ` Junio C Hamano
2016-03-25 20:14 ` [PATCH v3] " Pranit Bauva
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