GNU bug report logs - #1396
Idea: unify *newline(-and-indent)

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Message #3 received at quiet <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Daniel Colascione <danc <at> merrillpress.com>
To: quiet <at> debbugs.gnu.org
Subject: Idea: unify *newline(-and-indent)
Date: Sun, 31 Aug 2008 05:37:46 -0400

Severity: wishlist

[ resent from
  http://lists.gnu.org/archive/html/emacs-devel/2008-08/msg01461.html ]


The newline situation has annoyed me for a long time. Before fixing  
it, I figure I'll float the idea here and see what kind of reception I  
get.

In emacs CVS, I found these functions:

ada-indent-newline-indent-conditional
align-newline-and-indent
c-context-line-break
c-newline-and-indent
electric-pascal-terminate-line
electric-verilog-terminate-and-indent
electric-verilog-terminate-line
html-paragraph
idlwave-newline
m2-newline
message-newline-and-reformat
newline
newline-and-indent
octave-reindent-then-newline-and-indent
reindent-then-newline-and-indent
table--cell-newline-and-indent
vera-electric-return
vhdl-electric-return

I'm not even counting all the modes that aren't in CVS, or all the  
(reindent-)newline(-and-indent) functions grep couldn't find. Why do  
we need so many functions for essentially the same thing? Recently, I  
tried seeing whether I could make newline not kill trailing  
whitespace. I'd have to rewrite the newline function quite a few major  
modes, and the solution would still be brittle.

Why not unify all the newline-and-friends functions?

- Cull the above list to three functions
interactive-newline (new function)
newline-and-indent
reindent-then-newline-and-indent

- Change the C-m binding in bindings.el to interactive-newline.
- Define a new variable, interactive-newline-function, which defaults  
to #'newline.

(The existing #'newline would stay the same for backward  
compatibility. I see 122 direct calls to (newline) in current CVS, and  
I bet the callers wouldn't like new behavior.)

Change newline-and-indent and reindent-then-newline-and-indent to call  
interactive-newline instead of newline. Have interactive-newline call  
interactive-newline-function. (Which is plain old #'newline by  
default, remember.)

Then, take all the functions above and convert them to functions that  
can be plugged into interactive-newline-function. The situation we end  
up with something like indent-for-tab-command and indent-line-function.

Is it worth writing the patch?

Thanks,
Dan

(Also – any objections to making cc-mode and lisp-mode use indent-for- 
tab-command? The lisp tab command
has an indent-whole-sexp feature, but that be handled by passing the  
prefix argument to indent-line-function. The cc-mode indent function  
has some tab-or-indent DWIM feature, but isn't it better to put that  
in indent-for-tab-command by extending tab-always-indent?)

View this message in rfc822 format

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Daniel Colascione <danc <at> merrillpress.com>
Cc: 1396 <at> debbugs.gnu.org
Subject: bug#1396: Idea: unify *newline(-and-indent)
Date: Mon, 30 Sep 2019 09:19:10 +0200

Daniel Colascione <danc <at> merrillpress.com> writes:

> The newline situation has annoyed me for a long time. Before fixing  
> it, I figure I'll float the idea here and see what kind of reception I  
> get.
>
> In emacs CVS, I found these functions:
>
> ada-indent-newline-indent-conditional
> align-newline-and-indent
> c-context-line-break
> c-newline-and-indent
> electric-pascal-terminate-line
> electric-verilog-terminate-and-indent
> electric-verilog-terminate-line
> html-paragraph
> idlwave-newline
> m2-newline
> message-newline-and-reformat
> newline
> newline-and-indent
> octave-reindent-then-newline-and-indent
> reindent-then-newline-and-indent
> table--cell-newline-and-indent
> vera-electric-return
> vhdl-electric-return
>
> I'm not even counting all the modes that aren't in CVS, or all the  
> (reindent-)newline(-and-indent) functions grep couldn't find. Why do  
> we need so many functions for essentially the same thing?

I had a look at a handful, and they don't really do the same thing.  For
instance octave-reindent-then-newline-and-indent does some upcasing, and
message-newline-and-reformat inserts four newlines.

> Recently, I tried seeing whether I could make newline not kill
> trailing whitespace. I'd have to rewrite the newline function quite a
> few major modes, and the solution would still be brittle.

They all call `newline' in the end (as far as I can see), so the fix
could be done there.

> Then, take all the functions above and convert them to functions that  
> can be plugged into interactive-newline-function. The situation we end  
> up with something like indent-for-tab-command and indent-line-function.
>
> Is it worth writing the patch?

I think the use case is a bit iffy.  I do see the attraction of doing
something like indent-for-tab-command, but for newline, but...

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #10 received at 1396 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Daniel Colascione <danc <at> merrillpress.com>
Cc: 1396 <at> debbugs.gnu.org
Subject: Re: bug#1396: Idea: unify *newline(-and-indent)
Date: Thu, 03 Jun 2021 12:10:03 +0200

Lars Ingebrigtsen <larsi <at> gnus.org> writes:

>> I'm not even counting all the modes that aren't in CVS, or all the  
>> (reindent-)newline(-and-indent) functions grep couldn't find. Why do  
>> we need so many functions for essentially the same thing?
>
> I had a look at a handful, and they don't really do the same thing.  For
> instance octave-reindent-then-newline-and-indent does some upcasing, and
> message-newline-and-reformat inserts four newlines.

So I'm closing this bug report.  It may be that some of these functions
should be unified, but that has to be done on a case-to-case basis.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

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