Re: [RFC/PATCH v2 0/4] A new library for plumbing output

On Sat, Apr 17, 2010 at 03:02:39PM +0200, Jakub Narebski wrote:

Something like that (please remember that it is still in vague beginnings
of an idea stage:

  OUT_OBJECT(
     OUT_FIELD("mode",   OUT_MODE, tree.mode), SP,
     OUT_FIELD("type",   "%s", tree.object.type), SP,
     OUT_FIELD("object", OUT_SHA1, tree.object.sha1), TAB,
     OUT_FIELD("file", OUT_FILE(sep), tree.filename), 
     sep
  );

Doing that would require variadic macros, which are a C99-ism. So you
would have to do:

  OUT_OBJECT_START();
    OUT_FIELD("mode", OUT_MODE, tree.mode); OUT_SP;
    ...
  OUT_OBJECT_END();

which is not all that different from what Julian has now. I do think
some type-specific conversions might be handy. They don't even need to
be macros. E.g.,:

  void output_mode(struct output_context *oc, int mode)
  {
    output_strf(oc, "mode", "%06o", mode);
  }

OTOH, looking over Julian's last patch series, there really aren't that
many that would be generally applicable, and as you can see they only
save a few characters, not even a line. A few bigger objects could be
factored out, but he has already done that (e.g., see
wt_porcelain_unmerged in his v2 3/4).

-Peff