bug#55562: 28.1.50; Wrong hash table return values in Elisp manual

[Eli Zaretskii <eliz@gnu.org>]

[Adding Stefan and Daniel to the CC.]

> Date: Sat, 21 May 2022 23:29:04 +0300
> From:  "Basil L. Contovounesios" via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Severity: minor
> Tags: patch
> 
> 0. emacs -Q
> 1. C-h f clrhash RET
> 
> > Clear hash table TABLE and return it.
> 
> 2. C-h S clrhash RET
> 
> > Common Lisp note: In Common Lisp, ‘clrhash’ returns the empty
> > TABLE.  In Emacs Lisp, it returns ‘nil’.
> 
> It seems the following changes never propagated to the manual:
> 
> (Fputhash): Return `value' rather than nil.
> d9c4f922fb 2000-07-03 06:59:05 +0000
> https://git.sv.gnu.org/cgit/emacs.git/commit/?id=d9c4f922fb
> 
> * fns.c (Fputhash): Document return value.
> a54e348216 2011-06-06 18:39:26 -0700
> https://git.sv.gnu.org/cgit/emacs.git/commit/?id=a54e348216
> 
> And the following change wasn't announced in etc/NEWS either:
> 
> (Fclrhash): Return TABLE.
> ccd8f7fe14 2008-01-25 10:01:15 +0000
> https://git.sv.gnu.org/cgit/emacs.git/commit/?id=ccd8f7fe14
> 
> Is there any point in announcing the status quo, or can we just update
> the manual, e.g. as follows?
> 
> 
> >From b63ec2658f1c8782620c7418c8282f29249333cd Mon Sep 17 00:00:00 2001
> From: "Basil L. Contovounesios" <contovob@tcd.ie>
> Date: Sat, 21 May 2022 23:11:33 +0300
> Subject: [PATCH] Fix hash table function return values in manual
> 
> * doc/lispref/hash.texi (Hash Access): Reconcile documented return
> values of puthash and clrhash with their respective docstrings.
> ---
>  doc/lispref/hash.texi | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/doc/lispref/hash.texi b/doc/lispref/hash.texi
> index a566d89824..34eda45b23 100644
> --- a/doc/lispref/hash.texi
> +++ b/doc/lispref/hash.texi
> @@ -203,7 +203,8 @@ Hash Access
>  @defun puthash key value table
>  This function enters an association for @var{key} in @var{table}, with
>  value @var{value}.  If @var{key} already has an association in
> -@var{table}, @var{value} replaces the old associated value.
> +@var{table}, @var{value} replaces the old associated value.  This
> +function always returns @var{value}.
>  @end defun
>  
>  @defun remhash key table
> @@ -219,10 +220,7 @@ Hash Access
>  @defun clrhash table
>  This function removes all the associations from hash table @var{table},
>  so that it becomes empty.  This is also called @dfn{clearing} the hash
> -table.
> -
> -@b{Common Lisp note:} In Common Lisp, @code{clrhash} returns the empty
> -@var{table}.  In Emacs Lisp, it returns @code{nil}.
> +table.  @code{clrhash} returns the empty @var{table}.
>  @end defun
>  
>  @defun maphash function table
> -- 
> 2.35.1
> 
> Thanks,
> 
> -- 
> Basil
> 
> In GNU Emacs 28.1.50 (build 1, x86_64-pc-linux-gnu)
>  of 2022-05-21 built on tia
> Repository revision: 139bfa1a0884dbd2600fc1bd11d11f41d3f9ef94
> Repository branch: wt/emacs-28-nox
> System Description: Debian GNU/Linux bookworm/sid
> 
> Configured using:
>  'configure CC=gcc-12 'CFLAGS=-O2 -march=native'
>  --prefix=/home/blc/.local --program-suffix=-28-nox
>  --with-file-notification=yes --with-x-toolkit=no --without-x'
> 
> Configured features:
> ACL DBUS GMP GNUTLS GPM JSON LCMS2 LIBSELINUX LIBSYSTEMD LIBXML2 MODULES
> NOTIFY INOTIFY PDUMPER SECCOMP SOUND THREADS XIM ZLIB