bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Allen Li]

hideshow-minor-mode binds C-c @ C-h, preventing C-h from being used as
the help key to describe the bindings under the C-c @ prefix.

In GNU Emacs 25.1.91.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.8),
modified by Debian
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description: Ubuntu 14.04 LTS

Configured using:
 'configure --build x86_64-linux-gnu --build x86_64-linux-gnu
 --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/google-emacs:/etc/emacs:/usr/local/share/emacs/25.1.91+gg1+2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1.91+gg1+2/site-lisp:/usr/share/emacs/site-lisp
 --with-crt-dir=/usr/lib/x86_64-linux-gnu --disable-build-details
 --disable-silent-rules --with-modules GOOGLE_VERSION=25.1.91+gg1+2
 --with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars
 build_alias=x86_64-linux-gnu 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro
 -Wl,-fuse-ld=gold,--export-dynamic-symbol=__google_auxv'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2 -DGOOGLE_EMACS_DEFINE_AUXV''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Wed, 15 Feb 2017 14:30:34 -0800
> 
> hideshow-minor-mode binds C-c @ C-h, preventing C-h from being used as
> the help key to describe the bindings under the C-c @ prefix.

You can type "C-c @ ?" instead, i.e. use the question-mark '?' instead
of C-h.

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Allen Li]

On Wed, Feb 15, 2017 at 9:57 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> You can type "C-c @ ?" instead, i.e. use the question-mark '?' instead
> of C-h.

Ah, that's embarrassing.  Rereading the manual I see this
important bit that I have forgotten:

    You can get a list of subcommands for a particular prefix key by
    typing C-h, ?, or F1 (describe-prefix-bindings) after the prefix
    key. (There are a few prefix keys for which not all of these keys
    work—those that provide their own bindings for that key. One of
    these prefix keys is ESC, because ESC C-h is actually C-M-h,
    which marks a defun. However, ESC F1 and ESC ? work fine.)

I guess this is working as intended, then?  I was thinking of the
recommendation in the style guide, which I have read many times more
than the manual:

    Don’t bind C-h following any prefix character (including
    C-c). If you don’t bind C-h, it is automatically available as
    a help character for listing the subcommands of the prefix
    character.

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Thu, 16 Feb 2017 00:54:34 -0800
> Cc: 25747@debbugs.gnu.org
> 
>     You can get a list of subcommands for a particular prefix key by
>     typing C-h, ?, or F1 (describe-prefix-bindings) after the prefix
>     key. (There are a few prefix keys for which not all of these keys
>     work—those that provide their own bindings for that key. One of
>     these prefix keys is ESC, because ESC C-h is actually C-M-h,
>     which marks a defun. However, ESC F1 and ESC ? work fine.)
> 
> I guess this is working as intended, then?

I don't know, it could be.

> I was thinking of the recommendation in the style guide, which I
> have read many times more than the manual:
> 
>     Don’t bind C-h following any prefix character (including
>     C-c). If you don’t bind C-h, it is automatically available as
>     a help character for listing the subcommands of the prefix
>     character.

Perhaps we should make that somewhat softer, e.g. "We don't recommend
binding C-h ... if it can be avoided.." or somesuch.

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>>     You can get a list of subcommands for a particular prefix key by
>>     typing C-h, ?, or F1 (describe-prefix-bindings) after the prefix
>>     key. (There are a few prefix keys for which not all of these keys
>>     work—those that provide their own bindings for that key. One of
>>     these prefix keys is ESC, because ESC C-h is actually C-M-h,
>>     which marks a defun. However, ESC F1 and ESC ? work fine.)
>>
>> I guess this is working as intended, then?
>
> I don't know, it could be.
>
>> I was thinking of the recommendation in the style guide, which I
>> have read many times more than the manual:
>>
>>     Don’t bind C-h following any prefix character (including
>>     C-c). If you don’t bind C-h, it is automatically available as
>>     a help character for listing the subcommands of the prefix
>>     character.
>
> Perhaps we should make that somewhat softer, e.g. "We don't recommend
> binding C-h ... if it can be avoided.." or somesuch.

I think it's fine to maintain a firm recommendation.  Binding C-h is a
very poor choice, and should be discouraged accordingly.

I also think that "C-c @ C-h" is a very unfortunate keybinding, even if
it is mnemonic for "hide".  But it seems much too late to do anything
about that now.

So I don't think we should do anything here, besides closing this as
wontfix.  Any other opinions?

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Drew Adams]

> I also think that "C-c @ C-h" is a very unfortunate keybinding, even if
> it is mnemonic for "hide".

I agree.  There are other *hide* commands that don't use `C-h'
in their bindings.  There are even other hideshow hide commands
that don't use it:

C-c @ C-M-h
C-c @ C-l
C-c @ C-t
C-c @ C-d

There's anyway redundancy: C-c @ C-h is the same as C-c @ C-d.
(And C-c @ C-M-h is the same as C-c @ C-t.)  Are all of the
default bindings really necessary/useful?

(If you think it's important to have something that fits with
the `C-c @ C-M-h' of `hs-hide-all' then use `C-c @ M-h'.)

My guess is that the author just didn't know about using `C-h'
after a prefix arg.  And the more exceptions to that working,
the more people will do likewise: mistakenly (in ignorance)
bind `C-h' after a prefix key, preventing it from that use.

> But it seems much too late to do anything about that now.

Why is it too late?  Just drop `C-c @ C-h' - that's my suggestion.

bug#25747: 25.1.91; hideshow binding C-c @ C-h overrides help

[Lars Ingebrigtsen]

Stefan Kangas <stefan@marxist.se> writes:

> So I don't think we should do anything here, besides closing this as
> wontfix.  Any other opinions?

I agree that there doesn't seem to be anything to do here, so I'm
closing this bug report now.

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