From: Eli Zaretskii <eliz@gnu.org>
Date: Fri, 17 Sep 2021 12:03:53 +0000 (+0300)
Subject: Improve the documentation of a recent change
X-Git-Tag: emacs-28.0.90~902
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=3848e2727edab4a2bcb6bca52abae883e33ac90b;p=emacs.git

Improve the documentation of a recent change

* etc/NEWS:
* doc/lispref/sequences.texi (Sequence Functions): Improve
documentation of 'seq-union'.
---

diff --git a/doc/lispref/sequences.texi b/doc/lispref/sequences.texi
index 53d37199bf7..4a48d62f6db 100644
--- a/doc/lispref/sequences.texi
+++ b/doc/lispref/sequences.texi
@@ -957,9 +957,11 @@ contain less elements than @var{n}.  @var{n} must be an integer.  If
 @cindex sequences, union of
 @cindex union of sequences
   This function returns a list of the elements that appear either in
-@var{sequence1} or @var{sequence2}.  If the optional argument
-@var{function} is non-@code{nil}, it is a function of two arguments to
-use to compare elements instead of the default @code{equal}.
+@var{sequence1} or @var{sequence2}.  The elements of the returned list
+are all unique, in the sense that no two elements there will compare
+equal.  If the optional argument @var{function} is non-@code{nil}, it
+should be a function of two arguments to use to compare elements,
+instead of the default @code{equal}.
 
 @example
 @group
diff --git a/etc/NEWS b/etc/NEWS
index b1ad4dd1263..b10aa3b5a7d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -3858,7 +3858,8 @@ supporting Lisp files when 'require' is unsuitable.
 +++
 ** New function 'seq-union'.
 This function takes two sequences and returns a list of all elements
-that appear in either of them.
+that appear in either of them, with no two elements that compare equal
+appearing in the result.
 
 +++
 ** New function 'syntax-class-to-char'.