Re: [PATCH] refactor various if (x) FREE_AND_NULL(x) to just FREE_AND_NULL(x)

From: Jeff King <peff@peff.net>
Date: Aug 17, 2018, 17:39 UTC
Message-ID: <20180817173951.GA9474@sigill.intra.peff.net>
In-Reply-To: <20180817173308.GA9111@sigill.intra.peff.net>

On Fri, Aug 17, 2018 at 01:33:08PM -0400, Jeff King wrote:

Show 12 quoted lines

> > And revised even more to also spell "E" as "E != NULL" (and "!E" as
> > "E == NULL"), which seems to make a difference, which is even more
> > sad.  I do not want to wonder if I have to also add "NULL == E" and
> > other variants, so I'll stop here.
> 
> I think it makes sense that these are all distinct if you're using
> coccinelle to do stylistic transformations between them (e.g., enforcing
> curly braces even around one-liners).
> 
> I wonder if there is a way to "relax" a pattern where these semantically
> equivalent cases can all be covered automatically. I don't know enough
> about the tool to say.

Hmm. They seem to call these "standard isomorphisms":

  http://coccinelle.lip6.fr/standard.iso.html

but I'm not sure of the correct way to use them (e.g., if we want to apply them for matching but not actually transform the code, though I am not actually opposed to transforming the code, too).

-Peff