Re: [PATCH 06/19] reset.c: remove unnecessary variable 'i'

On Wed, Jan 9, 2013 at 11:39 AM, Junio C Hamano [off-list ref] wrote:

Martin von Zweigbergk [off-list ref] writes:

quoted

Throughout most of parse_args(), the variable 'i' remains at 0. In the
remaining few cases, we can do pointer arithmentic on argv itself
instead.
---
This is clearly mostly a matter of taste. The remainder of the series
does not depend on it in any way.

I agree that it indeed is a matter of taste between

 (1) look at av[i], check with (i < ac) for the end, and increment i to
     iterate over the arguments; and

 (2) look at av[0], check with (0 < ac) for the end, and increment
     av and decrement ac at the same time to iterate over the
     arguments.

When (ac, av) appear as a pair, however, adjusting only av without
adjusting ac is asking for future trouble.  It violates a common
expectation that av[ac] points at the NULL at the end of the list.

Good points.

If a code chooses to use !av[0] as the terminating condition and
never looks at ac, then incrementing only av is fine, but in such a
case, the function probably should lose ac altogether.

Makes sense. I've picked this style for now (i.e. dropped both 'i' and
'argc'). I was surprised by the style that referred to the variable in
many places where it was know to be 0, but I'm no experienced C
programmer, so if that's a common practice when it comes to argument
parsing, I'm also happy to drop the patch. Let me know what you
prefer.