From: Jeff King <peff@peff.net>
Date: Sat, 17 Apr 2010 14:00:53 GMT
Subject: Re: [RFC/PATCH v2 0/4] A new library for plumbing output
Message-ID: <20100417140053.GA10997@coredump.intra.peff.net>
In-Reply-To: <201004171502.42044.jnareb@gmail.com>

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