Re: [PATCH v11 2/4] parse-options.c: make OPTION_COUNTUP respect "unspecified" values

> Pranit Bauva <pranit.bauva@gmail.com> writes:
>
>> On Fri, Apr 1, 2016 at 12:11 AM, Junio C Hamano <gitster@pobox.com> wrote:
>>>
>>>         case OPTION_COUNTUP:
>>> +               if (*(int *)opt->value < 0)
>>> +                       *(int *)opt->value = 0;
>>>                 *(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
>>>
>>> That is, upon hitting this case arm, we know that an explicit option
>>> was given from the command line, so the "unspecified" initial value,
>>> if it is still there, gets reset to 0, and after doing that, we just
>>> do the usual thing.
>>
>> This does look cleaner. Nice thinking that there is no need to
>> actually specify when it gets 0. It gets 0 no matter what as long as
>> OPTION_COUNTUP is speficied in any format (with or without --no) and
>> variable is "unspecified".
>
> I do not think there is any planned users of such an enhancement,
> but the above points us into a future possibility to be able to do
> this:
>
>         case OPTION_COUNTUP:
> +               if (*(int *)opt->value < 0)
> +                       *(int *)opt->value = -*(int *)opt->value - 1;
>                 *(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
>
> That is, by using "-2" as the "unspecified" value, you can start
> counting up from 2 (i.e. the presence of the option resets the
> variable to 1 and then the option being not "unset" increments it)
> if your application wants to.