bug#46301: 28.0.50; cc-mode: add support for c++ lambda expression

[Alan Mackenzie <acm@muc.de>]

Hello, Utkarsh.

On Sat, Feb 27, 2021 at 21:17:11 +0530, Utkarsh Singh wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > I've spent the last couple of days fixing the handling of C-M-a/e in
> > cc-cmds.el.  It took rather more than the four line patch you proposed.
> > ;-)  Could I ask you, please, to apply the following patch (which should
> > apply cleanly to the Emacs master branch), byte compile cc-cmds.el, load
> > it into Emacs, and test it for me on your real source code.  Then please
> > report back whether the bug is in fact fixed, and if not, what is still
> > wrong.  In the event you would like help with the patching or byte
> > compiling, feel free to send me private email.

> Thanks now issue is fixed and code itself looks pretty solid.

Thanks for doing the testing.  I've committed the patch to all the
relevant places, and I'm closing the bug with this post.

> Due to my in-experience in Elisp and comprehensive cc-mode library I was
> unable to deep dive into the patch but I have a questions about it:

> Why non-interactive functions of cc-mode doesn't provide doc-string?

Quite a lot of functions, even non-interactive ones, and variables have
a doc string.  This means that those functions/variables are available
to modes derived from CC Mode, and their interfaces are fixed.  The ones
without doc strings are regarded as "internal" to CC Mode, and their
interfaces can (and do) change at any time.  There's a comment to this
effect burried in the first few hundred lines of cc-engine.el.

A few years ago, an alternative convention started being adopted by
Emacs, where a double hypen is used to indicate an "internal" function
or variable.

> --
> Utkarsh Singh

-- 
Alan Mackenzie (Nuremberg, Germany).