Re: [PATCH] grep: use OPT_INTEGER_F for --max-depth

> Am 07.09.23 um 22:40 schrieb Jeff King:
>
> I was thinking more about something like the solutions discussed at
> https://stackoverflow.com/questions/47674663/variable-arguments-inside-a-macro.
> It allows selecting variants based on argument count.
>
> That could look like this (untested except on https://godbolt.org/; the
> EVALs are needed for MSVC for some reason):
>
> #define OPT_INTEGER_FULL(s, l, v, h, f, d) { \
> 	.type = OPTION_INTEGER, \
> 	.short_name = (s), \
> 	.long_name = (l), \
> 	.value = (v), \
> 	.argh = N_("n"), \
> 	.help = (h), \
> 	.flags = (f), \
> 	.defval = (d), \
> }
> #define OPT_INTEGER_4(s, l, v, h) \
> 	OPT_INTEGER_FULL(s, l, v, h, 0, 0)
> #define OPT_INTEGER_5(s, l, v, h, f) \
> 	OPT_INTEGER_FULL(s, l, v, h, f, 0)
> #define OPT_INTEGER_6(s, l, v, h, f, d) \
> 	OPT_INTEGER_FULL(s, l, v, h, (f) | PARSE_OPT_OPTARG, d)
> #define EVAL(x) x
> #define SEVENTH(_1, _2, _3, _4, _5, _6, x, ...) x
> #define OPT_INTEGER(...) \
> 	EVAL(EVAL(SEVENTH(__VA_ARGS__, OPT_INTEGER_6, OPT_INTEGER_5, OPT_INTEGER_4, 0))(__VA_ARGS__))
>
> So OPT_INTEGER(s, l, v, h) would be the same as before.  Add an argument
> and it becomes current OPT_INTEGER_F, add another one and it acts as
> your _OPTARG_F variant.

>> So yeah, I think you'd really want a separate macro. The combinations
>> start to add up (or multiply up, if you prefer ;) ). They _could_ be
>> generated mechanically, I think, as they can all be implemented in terms
>> of a master macro that knows about all features:
>>
>>    #define OPT_BOOL_F(s, l, v, h, f) OPT_BOOL_ALL(s, l, v, h, f, 0)
>>    #define OPT_BOOL(s, l, v, h, f) OPT_BOOL_F(s, l, v, h, 0)
>
> The "f" arg needs to go...
>
>>    #define OPT_BOOL_OPTARG_F(s, l, v, h, arg) OPT_BOOL_ALL(s, l, v, h, f | PARSE_OPT_OPTARG, arg)
>
> ... here, possibly.
>
>>    #define OPT_BOOL_OPTARG(s, l, v, h, arg) OPT_BOOL_OPTARG_F(s, l, v, h, 0, arg)