Re: [PATCH] diff: "lisp" userdiff_driver

From: Scott L. Burson <scott@sympoiesis.com>
Date: Nov 27, 2025, 02:10 UTC
Message-ID: <CAF5LJ4AgJvMHej1uRm5Q0v_BTavmm+aXPBC-nGmBp9URX16Gkw@mail.gmail.com>
In-Reply-To: <CALnO6CBFKjewrkPeEUh7Q-A2dZ7Fknjy4DszG8xCKu-NvGETfQ@mail.gmail.com>

On Thu, Nov 20, 2025 at 8:47 AM D. Ben Knoble <ben.knoble@gmail.com> wrote:

Show 7 quoted lines

> Without "going there," I think there are enough differences to warrant
> a different driver. (OTOH, I have sometimes wanted to teach the Scheme
> driver that most "def" things are probably definitions.) Our
> indentation is less rigid in that indented forms may be more deeply
> nested than only one or two spaces (and we of course have more
> definition forms than "only things starting with def"), and I don't
> understand the downthread desire to not permit tabs.

The proposal on the table is not to replace the current Scheme regexp with the Lisp one, but rather to disjoin them, so as to match any line that either one would match. So you don't need to worry about false negatives.

The thing about tabs was that, the way I had initially written the regexp, it would have matched a line starting with one or two tabs, or a tab and a space -- but no other whitespace -- followed by "(def". This was not my intention. I was just trying to match lines starting with a space or two and "(def". Again, this is in addition to the lines currently being matched by the Scheme regexp.

> As for Scheme community, I'll suggest asking on the Racket channels
> (Discourse is probably best if you want a mailing-list-like
> discussion?)

I have asked on Reddit under /r/scheme, and got only the same objection that you offered ("define" etc. forms more deeply nested), with the same resolution (disjoining the new pattern to the existing one).

Reddit says my post got some 4300 views. That seems like an adequate sample to me, but I can try elsewhere if you think it's important.

I have an updated version of the patch ready; I will submit it shortly.