GNU bug report logs - #78930
30.1; (elisp) `Mapping Functions"

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: "bug-gnu-emacs <at> gnu.org" <bug-gnu-emacs <at> gnu.org>
Subject: 30.1; (elisp) `Mapping Functions"
Date: Mon, 30 Jun 2025 16:39:26 +0000

On the one hand, this doc says that functions "mapcar, mapc, mapconcat,
and mapcan, ...  map over a _list_".  On the other hand, it says that
mapcar and mapcan map over a _sequence_ (except a char table) and return
a list, and mapconcat maps over a sequence (except a char table) and
returns a sequence of chars.

"Mapping over a <TYPE>" means that TYPE is the type of input.  All of
the mapping functions documented here map over _sequences_ (that are not
char tables).  They're not limited to mapping over _lists_.  Other
mapping functions mentioned (but not doc'd) here map over other
(non-sequence, non-list) types of collections.

The first sentence of the node is general enough, saying that a mapping
function maps over "a list or other collection".  But the next sentence
is problematic.  It should be enough to fix the second sentence (e.g.
by changing "list" to "sequence"; the rest of the node is OK.


In GNU Emacs 30.1 (build 2, x86_64-w64-mingw32) of 2025-02-23 built on
 AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.26100
System Description: Microsoft Windows 10 Pro (v10.0.2009.26100.4061)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation=aot
 --without-compress-install --with-tree-sitter CFLAGS=-O2
 prefix=/g/rel/install/emacs-30.1'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

(NATIVE_COMP present but libgccjit not available)

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Message #10 received at 78930-done <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 78930-done <at> debbugs.gnu.org
Subject: Re: bug#78930: 30.1; (elisp) `Mapping Functions"
Date: Mon, 30 Jun 2025 22:07:25 +0300

> Date: Mon, 30 Jun 2025 16:39:26 +0000
> From:  Drew Adams via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
> 
> On the one hand, this doc says that functions "mapcar, mapc, mapconcat,
> and mapcan, ...  map over a _list_".  On the other hand, it says that
> mapcar and mapcan map over a _sequence_ (except a char table) and return
> a list, and mapconcat maps over a sequence (except a char table) and
> returns a sequence of chars.

Thanks, fixed on the emacs-30 release branch, and closing the bug.

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