Reported by: bea <at> klebe.blog
Date: Tue, 18 Dec 2018 17:48:02 UTC
Severity: normal
Found in version 26.1
Done: Alan Mackenzie <acm <at> muc.de>
Bug is archived. No further changes may be made.
Message #23 received at 33794 <at> debbugs.gnu.org (full text, mbox):
From: Beatrix Klebe <beeuhtricks <at> gmail.com> To: João Távora <joaotavora <at> gmail.com> Cc: Alan Mackenzie <acm <at> muc.de>, "Mx. Beatrix Klebe" <bea <at> klebe.blog>, Stefan Monnier <monnier <at> iro.umontreal.ca>, 33794 <at> debbugs.gnu.org Subject: Re: bug#33794: 26.1; electric-pair-mode breaks auto-newline minor mode of cc-mode Date: Fri, 21 Dec 2018 14:06:34 -0500
Here's the link, I believe it was Stefan that answered it:
https://emacs.stackexchange.com/questions/2837/automatically-formatting-brackets/2853#2853
I have tried this with emacs -Q and it does not fix the issue, which
is as follows.
Ordinarily in cc-mode when you have auto-newline-mode activated, and
as far as I can tell, a cc-mode configuration that supports it, (which
csharp-mode contains), the following happens when opening a block
(pipe is the cursor):
void Main() {| // opening bracket is typed
becomes
void Main
{
|
when c-toggle-auto-newline is activated. However, if you also want
your braces automatically paired, with electric-pair-mode, instead the
following occurs:
void Main() {| // opening bracket is typed
void Main() {|} // electric-pair-mode closes the open bracket, but
auto-newline-mode does not appear to do anything.
void Main() {
|
} // user hits return, inserting the cursor at the correct indent
level, but leaving the opening brace where it is.
The ideal/desired behavior is:
void Main() {| // opening bracket is typed
void Main()
{
|
} // user hits return key, electric-pair-mode pairs up the brackets,
and auto-newline-mode formats the braces correctly
It would also probably suffice to format with the newline before
hitting enter as well, although I think I prefer hitting enter to open
the block. I'm quite curious as to the internals of these formatting
systems and would be happy to help with a fix/feature if that would be
desired, I am mostly an OCaml programmer but C# is my day job and I've
just recently gotten deeper into Emacs Lisp.
On Fri, Dec 21, 2018 at 1:49 PM João Távora <joaotavora <at> gmail.com> wrote:
>
> Beatrix Klebe <beeuhtricks <at> gmail.com> writes:
>
> > I believe I saw your Stack Overflow answer about this while searching
> > for the solution. electric-layout-mode works with some quirks, such as
> > that if you put a space after parens in a function definition, the
> > space gets carried on to the newline with that method, which is a bit
> > annoying. What would be ideal, and what I'm looking for, is to get
> > auto-pairing of brackets with braces being placed where they should be
> > automatically and the insertion point getting put in between them at
> > the correct indent level, such as what happens with Visual Studio, or
> > Visual Studio Code, or several other editors with this functionality.
> > Perhaps it is not emacslike to have such behavior be totally
> > automated, but I am used to it and finds it decreases my ordinary
> > levels of frustration when working with verbose and imperative
> > languages. I am currently trying to write some insert specifiers for
> > smartparens to do this, but it is proving more difficult to find an
> > elegant solution than I had expected.
>
> It is quite emacslike (though maybe not activated by default): you just
> have to report the bugs to the Emacs developers as efficiently as
> possible.
>
> 1. Though Alan possibly has already, I still cannot understand the
> original problem. Can you start by describing what the buffer looked
> like before, what you did, what it looked like afterwards, and what
> you expected it to look like? If possible start with a clean Emacs
> -Q recpe.
>
> 2. I have experimented with nicer-playing like alternatives like
> electric-layout-mode. I came across a few quirks myself (though I'm
> not sure if they are the same as yours). So I prepared a patch (in
> branch scratch/fix-33794-extend-electric-layout-mode) and attached
> it after the sig.
>
> After loading this patch, in a simple Emacs -Q the configuration:
>
> (electric-pair-mode)
> (electric-layout-mode)
>
> (add-hook 'c-mode-hook
> (lambda ()
> (setq-local electric-layout-rules
> '((?\{ . after)
> (?\{ . after-stay)))))
>
> And, when visiting a C file, if I press `{' I get the expected
> pair+layout+indent behaviour. Sor example opening a brace after
> int main () gives me:
>
> int main () {
> <cursor here>
> }
>
> I, like Stefan, think cc-mode could/should set electric-layout-rules
> buffer-locally to reflect whatever c-style the user has selected.
>
> Thanks,
> João
>
> PS: Also, can you link to the the relevant to the stack overflow answer you
> mentioned?
>
> commit ab036bdedbb49ecc96d550b5e883e43bb03eaccc
> Author: João Távora <joaotavora <at> gmail.com>
> Date: Fri Dec 21 18:00:08 2018 +0000
>
> Extend electric-layout-mode to handle more complex layouts
>
> Also, have it play nice with electric-pair-mode.
>
> Multiple matching entries in `electric-layout-rules' are executed in
> order of appearance. When inserting a newline in the 'after-stay
> rule, ensure electric-pair-open-newline-between-pairs is nil.
>
> Arguably the logic behind electric-pair-open-newline-between-pairs
> should be moved to electric-layout-mode, but the current rule-matching
> engine doesn't allow for it. The current solution seems to be good
> enough for the situations reported in bug#33794.
>
> * lisp/electric.el (electric-layout-rules): Adjust docstring.
> (electric-layout-post-self-insert-function): Loop through rules. Bind
> electric-pair-open-newline-between-pairs to nil when handling
> after-stay.
>
> diff --git a/lisp/electric.el b/lisp/electric.el
> index 6dbf46b80c..6a307a49b9 100644
> --- a/lisp/electric.el
> +++ b/lisp/electric.el
> @@ -370,38 +370,43 @@ electric-layout-rules
>
> The symbols specify where in relation to CHAR the newline
> character(s) should be inserted. `after-stay' means insert a
> -newline after CHAR but stay in the same place.")
> +newline after CHAR but stay in the same place.
> +
> +If multiple rules match, they are all executed in order of
> +appearance.")
>
> (defun electric-layout-post-self-insert-function ()
> - (let* ((rule (cdr (assq last-command-event electric-layout-rules)))
> - pos)
> - (when (and rule
> - (setq pos (electric--after-char-pos))
> + (let (pos)
> + (when (and (setq pos (electric--after-char-pos))
> ;; Not in a string or comment.
> (not (nth 8 (save-excursion (syntax-ppss pos)))))
> - (let ((end (point-marker))
> - (sym (if (functionp rule) (funcall rule) rule)))
> - (set-marker-insertion-type end (not (eq sym 'after-stay)))
> - (goto-char pos)
> - (pcase sym
> - ;; FIXME: we used `newline' down here which called
> - ;; self-insert-command and ran post-self-insert-hook recursively.
> - ;; It happened to make electric-indent-mode work automatically with
> - ;; electric-layout-mode (at the cost of re-indenting lines
> - ;; multiple times), but I'm not sure it's what we want.
> - ;;
> - ;; FIXME: check eolp before inserting \n?
> - ('before (goto-char (1- pos)) (skip-chars-backward " \t")
> - (unless (bolp) (insert "\n")))
> - ('after (insert "\n"))
> - ('after-stay (save-excursion
> - (let ((electric-layout-rules nil))
> - (newline 1 t))))
> - ('around (save-excursion
> - (goto-char (1- pos)) (skip-chars-backward " \t")
> - (unless (bolp) (insert "\n")))
> - (insert "\n"))) ; FIXME: check eolp before inserting \n?
> - (goto-char end)))))
> + (goto-char pos)
> + (dolist (rule electric-layout-rules)
> + (when (eq last-command-event (car rule))
> + (let* ((end (point-marker))
> + (rule (cdr rule))
> + (sym (if (functionp rule) (funcall rule) rule)))
> + (set-marker-insertion-type end (not (eq sym 'after-stay)))
> + (pcase sym
> + ;; FIXME: we used `newline' down here which called
> + ;; self-insert-command and ran post-self-insert-hook recursively.
> + ;; It happened to make electric-indent-mode work automatically with
> + ;; electric-layout-mode (at the cost of re-indenting lines
> + ;; multiple times), but I'm not sure it's what we want.
> + ;;
> + ;; FIXME: check eolp before inserting \n?
> + ('before (goto-char (1- pos)) (skip-chars-backward " \t")
> + (unless (bolp) (insert "\n")))
> + ('after (insert "\n"))
> + ('after-stay (save-excursion
> + (let ((electric-layout-rules nil)
> + (electric-pair-open-newline-between-pairs nil))
> + (newline 1 t))))
> + ('around (save-excursion
> + (goto-char (1- pos)) (skip-chars-backward " \t")
> + (unless (bolp) (insert "\n")))
> + (insert "\n"))) ; FIXME: check eolp before inserting \n?
> + (goto-char end)))))))
>
> (put 'electric-layout-post-self-insert-function 'priority 40)
>
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