bug#46889: cperl-mode: Fix indentation issues [PATCH]

[Lars Ingebrigtsen <larsi@gnus.org>]

haj@posteo.de (Harald Jörg) writes:

> As a by-catch, the new code fixes the ancient Bug#8077.
>
> This patch also fixes the first part of Bug#11733.  The "other
> indentation bug" reported in Bug#11733 (using a colon as a Perl regexp
> terminator) is a different story and not covered by this patch.
>
> Also fixed now (without known bug number): labels with a space before,
> or a comment after the colon are now correctly indented and fontified.

Sounds good.

> With this patch in effect, CPerl mode should finally have caught up with
> Perl 5.30!

:-)

> Many thanks to Mattias Engdegård for his patient explanations how rx
> expressions can be used without breaking compatibility to Emacs 26.1.
> Until now, this allowed two ugly regexp literals to be eliminated.

Funnily enough, that's the one thing I was going to ask you about with
this patch.

I'm not an experienced rx user -- at all -- but is this the best way to
do this?

> +(eval-and-compile
> +  (defconst cperl--ws-rx
> +    '(sequence (or space "\n"))

It was the eval-and-compile that made me look at this bit...

[...]

> +(defconst cperl-maybe-white-and-comment-rex
> +  (rx-to-string `(group (eval cperl--ws*-rx)))

I'm thinking of the rx `eval' things everywhere.  Wouldn't defining
these rx expressions with `rx-define' be more straighforward, and then
you'd have:

> +(defconst cperl-maybe-white-and-comment-rex
> +  (rx-to-string `(group cperl--ws*-rx))

(Similarly for basically all the rx `eval' bits.

Now, rx expands the `eval' at compile time, I think, so it doesn't
really make that much difference in practice, but it seems slightly
clearer, perhaps?

(Added Mattias to the CCs.)

-- 
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   bloggy blog: http://lars.ingebrigtsen.no