Re: Is Elisp really that slow?

[Ergus]

On Wed, May 15, 2019 at 10:29:42AM -0700, Drew Adams wrote:
> > > And, as already mentioned, comment-dwim is not an
> > > alternative to comment-region. They do different
> > > things.
> >
> > I beg to differ.
>
> And your begged difference, which presumably shows
> that they do NOT do different things, is what? ;-)
>
> I have nothing special to say here about `C-c C-c'
> or `cc-mode'.  But I will say I agree with Oscar
> that `comment-dwim' and `comment-region' have
> different behaviors - so neither is a substitute
> for the other.
>
> In particular, `comment-region' lets you also
> uncomment, including unnest, comments.

To no waste bindings we could just modify comment-region to accept
negative prefix to uncomment. So C-- M-; uncoments region, and M-;
comments it. But now there will come another user saying that the dwim
version is better... we will never agree in anything this way.

> I use both, and I bind each to a short key sequence.
>
> More precisely, I leave `comment-dwim' on `M-;'
> and I bind `C-x C-;' to a command similar to
> `comment-region' but that I find more useful:
> `comment-region-lines'.  It comments/uncomments
> whole lines.
>
> (So it too differs from `comment-region' - so it
> too is not an exact "replacement".)
>
> As for key bindings:
>
> Although I haven't bothered to change the binding of
> `M-;', I think it's a shame and a waste to sacrifice
> such a nice, short, _repeatable_ key sequence for a
> command that does _nothing_ when you repeat it.
>
> Far better to use `M-;' for some command that keeps
> doing something when repeated (just hold down `M-;').
> That's what Emacs should do eventually, IMHO.  No
> urgency, but someday, when we find a really useful
> repeatable command...
>
> As for `comment-dwim': Since I use `C-x C-;'
> (`comment-region-lines') for block commenting and
> uncommenting, I never really use `M-;' for anything
> other than an end-of-line comment.
>
> `M-;' used to be bound to a command that did only
> that: `indent-for-comment'.  And since that's all
> I really use `M-;' for, the rest of `comment-dwim'
> is, yes, wasted and replaceable by `comment-region'
> or my `comment-region-line'.  `M-;' for eol comment,
> `C-x C-;' for commenting/uncommenting lines.
>
> (defun comment-region-lines (beg end &optional arg)
>  "Like `comment-region', but comment/uncomment whole lines."
>  (interactive "*r\nP")
>  (when (> beg end)
>    (setq beg  (prog1 end (setq end  beg))))
>  (let ((bol  (save-excursion
>                (goto-char beg)
>                (line-beginning-position)))
>        (eol  (save-excursion
>                (goto-char end)
>                (if (bolp) (point) (line-end-position)))))
>    (comment-region bol eol arg)))

This is the king of features I would really support. Enable line or
region by default. There is a package for that in melpa y find very
useful.