varargs macros and ##

[Bruce Korb]

Zack Weinberg wrote:
> #    It might be better to discard the last preprocessor token instead
> # of the last preceding sequence of non-whitespace characters; in
> # fact, we may someday change this feature to do so.  We advise you...
> 
> ....  Now, it happens that I
> am reimplementing macro expansion, and it will be much easier for the
> reimplementation to discard the last preprocessor token.  It's my
> opinion that it is definitely better to do so; the behavior is less
> surprising to the user, and much more likely to be what they wanted.
> 
> Does anyone object to my changing this behavior?

Do it.  If it ever gets into a C spec someday, it will certainly
be this behavior, and not the non-whitespace-gobbling behavior!
Unless, of course, it is constrained to only gobbling a single
comma.  There really is not any need to gobble anything else.  :-)
With such a constraint:

  #define foo( x... )   ....

becomes usable.  (I am aware of the lack of symmetry with the
procedure header. :)