terminal scrolling in help

terminal scrolling in help

[Colin Baxter 😺]

Hello,

1. emacs-27.2 -nw -Q <RET>
2. C-h ?

The user is then told to use Space or Del to scroll options. This works
in xterm, stterm and urxvt.

In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
<PageDown>, <PageUp> to scroll, neither of which work in xterm,
stterm or urxvt

I am wondering why the scroll advice was changed?

Best wishes,

Colin Baxter.

Re: terminal scrolling in help

[Eli Zaretskii]

> From: Colin Baxter 😺 <m43cap@yandex.com>
> Cc: 
> Date: Mon, 13 Dec 2021 07:39:02 +0000
> 
> 1. emacs-27.2 -nw -Q <RET>
> 2. C-h ?
> 
> The user is then told to use Space or Del to scroll options. This works
> in xterm, stterm and urxvt.
> 
> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
> stterm or urxvt
> 
> I am wondering why the scroll advice was changed?

How about providing a patch that adds SPC and DEL to the advice?

Re: terminal scrolling in help

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Colin Baxter 😺 <m43cap@yandex.com>
>> Cc:
>> Date: Mon, 13 Dec 2021 07:39:02 +0000
>>
>> 1. emacs-27.2 -nw -Q <RET>
>> 2. C-h ?
>>
>> The user is then told to use Space or Del to scroll options. This works
>> in xterm, stterm and urxvt.
>>
>> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
>> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
>> stterm or urxvt
>>
>> I am wondering why the scroll advice was changed?

Because those are more natural keys to use on graphical displays.

> How about providing a patch that adds SPC and DEL to the advice?

Can we detect that we are running in a terminal and show SPC and DEL
there, while showing <PageDown> and <PageUp> on graphical displays?

Re: terminal scrolling in help

[Alan Mackenzie]

Hello, Stefan.

On Mon, Dec 13, 2021 at 05:49:36 -0800, Stefan Kangas wrote:
> Eli Zaretskii <eliz@gnu.org> writes:

> >> From: Colin Baxter 😺 <m43cap@yandex.com>
> >> Cc:
> >> Date: Mon, 13 Dec 2021 07:39:02 +0000

> >> 1. emacs-27.2 -nw -Q <RET>
> >> 2. C-h ?

> >> The user is then told to use Space or Del to scroll options. This works
> >> in xterm, stterm and urxvt.

> >> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
> >> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
> >> stterm or urxvt

> >> I am wondering why the scroll advice was changed?

> Because those are more natural keys to use on graphical displays.

> > How about providing a patch that adds SPC and DEL to the advice?

> Can we detect that we are running in a terminal and show SPC and DEL
> there, while showing <PageDown> and <PageUp> on graphical displays?

Probably not reliably.  On my Linux console, <PageUp/Down> work just
fine.

How about showing both pairs of key bindings?

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: terminal scrolling in help

[Stefan Kangas]

Alan Mackenzie <acm@muc.de> writes:

>> Can we detect that we are running in a terminal and show SPC and DEL
>> there, while showing <PageDown> and <PageUp> on graphical displays?
>
> Probably not reliably.  On my Linux console, <PageUp/Down> work just
> fine.
>
> How about showing both pairs of key bindings?

Yup, Eli installed that fix on the emacs-28 branch.

Re: terminal scrolling in help

[Eli Zaretskii]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Mon, 13 Dec 2021 05:49:36 -0800
> Cc: emacs-devel@gnu.org
> 
> >> I am wondering why the scroll advice was changed?
> 
> Because those are more natural keys to use on graphical displays.
> 
> > How about providing a patch that adds SPC and DEL to the advice?
> 
> Can we detect that we are running in a terminal and show SPC and DEL
> there, while showing <PageDown> and <PageUp> on graphical displays?

We can, but why?  PageUp/PageDown are available on some terminals as
well, and SPC/DEL are available on GUI displays.

Re: terminal scrolling in help

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>> Can we detect that we are running in a terminal and show SPC and DEL
>> there, while showing <PageDown> and <PageUp> on graphical displays?
>
> We can, but why?  PageUp/PageDown are available on some terminals as
> well, and SPC/DEL are available on GUI displays.

It seems suboptimal to print PageUp/PageDown if they won't work.

Re: terminal scrolling in help

[Eli Zaretskii]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Mon, 13 Dec 2021 10:12:34 -0800
> Cc: m43cap@yandex.com, emacs-devel@gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Can we detect that we are running in a terminal and show SPC and DEL
> >> there, while showing <PageDown> and <PageUp> on graphical displays?
> >
> > We can, but why?  PageUp/PageDown are available on some terminals as
> > well, and SPC/DEL are available on GUI displays.
> 
> It seems suboptimal to print PageUp/PageDown if they won't work.

I don't think we can know whether they do work on a given terminal.

Re: terminal scrolling in help

[James Cloos]

>>>>> "SK" == Stefan Kangas <stefankangas@gmail.com> writes:

SK> Because those are more natural keys to use on graphical displays.

not in general they are not.

on this keyboard they are tiny keys off by the cursor keys.  i have to
look to be sure i get them when wanted.

i have other keyboards where one must press a function key to access
those two at all.  meaing always a two-hand requirement.  quite hard
post-stroke.

space and backspace, otoh, are always easy to use.

(<backspace>, of course, translates to <DEL>, where <delete> translates
to <deletechar>; and it has been decades since i've seen/used a keyboard
which labels the ascii 0x7F key "Delete" rather than "Backspace"; so the
doc really ought to be Space/Backspace these days.)

-JimC
-- 
James Cloos <cloos@jhcloos.com>         OpenPGP: 0x997A9F17ED7DAEA6

Re: terminal scrolling in help

[Eli Zaretskii]

> Date: Mon, 13 Dec 2021 14:58:59 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> > From: Colin Baxter 😺 <m43cap@yandex.com>
> > Cc: 
> > Date: Mon, 13 Dec 2021 07:39:02 +0000
> > 
> > 1. emacs-27.2 -nw -Q <RET>
> > 2. C-h ?
> > 
> > The user is then told to use Space or Del to scroll options. This works
> > in xterm, stterm and urxvt.
> > 
> > In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
> > <PageDown>, <PageUp> to scroll, neither of which work in xterm,
> > stterm or urxvt
> > 
> > I am wondering why the scroll advice was changed?
> 
> How about providing a patch that adds SPC and DEL to the advice?

I installed a fix on the release branch, please test.

Thanks.

Re: terminal scrolling in help

[Colin Baxter 😺]

>>>>> Eli Zaretskii <eliz@gnu.org> writes:

    >> Date: Mon, 13 Dec 2021 14:58:59 +0200 From: Eli Zaretskii
    >> <eliz@gnu.org> Cc: emacs-devel@gnu.org
    >> 
    >> > From: Colin Baxter 😺 <m43cap@yandex.com> > Cc: > Date: Mon, 13
    >> Dec 2021 07:39:02 +0000
    >> > 
    >> > 1. emacs-27.2 -nw -Q <RET> > 2. C-h ?
    >> > 
    >> > The user is then told to use Space or Del to scroll
    >> options. This works > in xterm, stterm and urxvt.
    >> > 
    >> > In emacs-28.0.90 (and emacs-29.0.50) the user is now told to
    >> use > <PageDown>, <PageUp> to scroll, neither of which work in
    >> xterm, > stterm or urxvt
    >> > 
    >> > I am wondering why the scroll advice was changed?
    >> 
    >> How about providing a patch that adds SPC and DEL to the advice?

    > I installed a fix on the release branch, please test.

Thank you. Tested on emacs-28.0.90 - works - simple but effective!

Best wishes.

Re: terminal scrolling in help

[Yuri Khan]

On Mon, 13 Dec 2021 at 14:41, Colin Baxter 😺 <m43cap@yandex.com> wrote:

> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
> stterm or urxvt

You should really get that diagnosed. PageUp/PageDown are supposed to
work in all of the above; they emit ESC [ 5 ~ and ESC [ 6 ~ which are
decoded to [prior] and [next] in term/xterm.el which term/rxvt.el and
term/st.el build on.

Re: terminal scrolling in help

[Colin Baxter 😺]

>>>>> Yuri Khan <yuri.v.khan@gmail.com> writes:

    > On Mon, 13 Dec 2021 at 14:41, Colin Baxter 😺 <m43cap@yandex.com> wrote:
    >> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
    >> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
    >> stterm or urxvt

    > You should really get that diagnosed. PageUp/PageDown are supposed
    > to work in all of the above; they emit ESC [ 5 ~ and ESC [ 6 ~
    > which are decoded to [prior] and [next] in term/xterm.el which
    > term/rxvt.el and term/st.el build on.

Well [5~ and [6~ do appear in the scratch buffer but that's all.

Re: terminal scrolling in help

[Yuri Khan]

On Tue, 14 Dec 2021 at 00:35, Colin Baxter 😺 <m43cap@yandex.com> wrote:

>     > You should really get that diagnosed. PageUp/PageDown are supposed
>     > to work in all of the above; they emit ESC [ 5 ~ and ESC [ 6 ~
>     > which are decoded to [prior] and [next] in term/xterm.el which
>     > term/rxvt.el and term/st.el build on.
>
> Well [5~ and [6~ do appear in the scratch buffer but that's all.

So, for each of the terminals you’d like to investigate: what is your
$TERM environment variable set to, what is your input-decode-map like,
and are you using any terminal multiplexer such as screen or tmux?

Re: terminal scrolling in help

[Colin Baxter 😺]

>>>>> Yuri Khan <yuri.v.khan@gmail.com> writes:

    > On Tue, 14 Dec 2021 at 00:35, Colin Baxter 😺 <m43cap@yandex.com> wrote:
    >> > You should really get that diagnosed. PageUp/PageDown are
    >> supposed > to work in all of the above; they emit ESC [ 5 ~ and
    >> ESC [ 6 ~ > which are decoded to [prior] and [next] in
    >> term/xterm.el which > term/rxvt.el and term/st.el build on.
    >> 
    >> Well [5~ and [6~ do appear in the scratch buffer but that's all.

    > So, for each of the terminals you’d like to investigate: what is
    > your $TERM environment variable set to, what is your
    > input-decode-map like, and are you using any terminal multiplexer
    > such as screen or tmux?

Well TERM is xterm-256color in xterm and zsh, but st-256color in stterm
and screen-256color in tmux. For the input-decode-map, do you mean the
output from the emacs variable "input-decode-map"? I'm using emacs -Q so
the variable value covers many lines - do you want all of that?

Best wishes

Re: terminal scrolling in help

[Yuri Khan]

On Tue, 14 Dec 2021 at 02:05, Colin Baxter 😺 <m43cap@yandex.com> wrote:

> Well TERM is xterm-256color in xterm and zsh, but st-256color in stterm
> and screen-256color in tmux.

Looks sane. (Except that zsh is not a terminal emulator.)

> For the input-decode-map, do you mean the
> output from the emacs variable "input-decode-map"? I'm using emacs -Q so
> the variable value covers many lines - do you want all of that?

Just see if it has these entries:

(keymap
 (27 keymap                   ;; ESC
     (91 keymap               ;; [
         (53 keymap           ;; 5
             (126 . [prior])  ;; ~
             …)
         (54 keymap           ;; 6
             (126 . [next])   ;; ~
             …)
         …)
     …)
 …)

Also, you don’t do anything funny like remapping ESC, do you?

Re: terminal scrolling in help

[Colin Baxter 😺]

>>>>> Yuri Khan <yuri.v.khan@gmail.com> writes:

    > On Tue, 14 Dec 2021 at 02:05, Colin Baxter 😺 <m43cap@yandex.com> wrote:
    >> Well TERM is xterm-256color in xterm and zsh, but st-256color in
    >> stterm and screen-256color in tmux.

    > Looks sane. (Except that zsh is not a terminal emulator.)

    >> For the input-decode-map, do you mean the output from the emacs
    >> variable "input-decode-map"? I'm using emacs -Q so the variable
    >> value covers many lines - do you want all of that?

    > Just see if it has these entries:

    > (keymap (27 keymap ;; ESC (91 keymap ;; [ (53 keymap ;; 5 (126
    > . [prior]) ;; ~ …)  (54 keymap ;; 6 (126 . [next]) ;; ~ …)  …)  …)
    > …)

Yes, there are there. I get


--8<---------------cut here---------------start------------->8---

Value:
(keymap
  (27 keymap
      (91 keymap
          (53 keymap
              (126 .
                   [prior])
              (59 keymap
                  (50 keymap
                      (126 .
                           [S-prior]))))
          (54 keymap

--8<---------------cut here---------------end--------------->8---


> Also, you don’t do anything funny like remapping ESC, do you?

Well I do have

--8<---------------cut here---------------start------------->8---
XTerm*metaSendsEscape: true
--8<---------------cut here---------------end--------------->8---

in ~/.Xdefaults. I did commented that out and it had no effect. Also I
had moved out the way my ~/.Xdefaults (and ~/.Xresources) but again
there was no difference.

I should point out that <PageUp> and <PageDown> do work in xterm (using
emacs-29.0.50) for other buffers (e.g. the buffer produced by C-h v for
the input-decode-map variable). It is in the mini-buffer produced by "C-h
?" where the keys don't work. I haven't checked all buffers.

Best wishes,

Re: terminal scrolling in help

[Andreas Schwab]

On Dez 14 2021, Yuri Khan wrote:

> On Tue, 14 Dec 2021 at 02:05, Colin Baxter 😺 <m43cap@yandex.com> wrote:
>
>> Well TERM is xterm-256color in xterm and zsh, but st-256color in stterm
>> and screen-256color in tmux.
>
> Looks sane. (Except that zsh is not a terminal emulator.)
>
>> For the input-decode-map, do you mean the
>> output from the emacs variable "input-decode-map"? I'm using emacs -Q so
>> the variable value covers many lines - do you want all of that?
>
> Just see if it has these entries:

The problem is that help-for-help uses an overriding-local-map that
makes almost all keys undefined, including the ESC key.  If ESC where
bound to nil, all the input-decode-map mappings would still work.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: terminal scrolling in help

[Andreas Schwab]

On Dez 13 2021, Colin Baxter 😺 wrote:

> In emacs-28.0.90 (and emacs-29.0.50) the user is now told to use
> <PageDown>, <PageUp> to scroll, neither of which work in xterm,
> stterm or urxvt

That looks like a bug.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."