From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#30816: 27.0.50; Info documentation of previous-property-change is not very clear Date: Wed, 14 Mar 2018 18:26:46 +0200 Message-ID: <833712sjw9.fsf@gnu.org> References: Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1521044708 8369 195.159.176.226 (14 Mar 2018 16:25:08 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 14 Mar 2018 16:25:08 +0000 (UTC) Cc: 30816@debbugs.gnu.org To: Xu Chunyang Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Mar 14 17:25:04 2018 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ew9D5-00021Z-T4 for geb-bug-gnu-emacs@m.gmane.org; Wed, 14 Mar 2018 17:25:04 +0100 Original-Received: from localhost ([::1]:47246 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ew9F8-0004Vq-TR for geb-bug-gnu-emacs@m.gmane.org; Wed, 14 Mar 2018 12:27:10 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47708) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ew9F2-0004VR-He for bug-gnu-emacs@gnu.org; Wed, 14 Mar 2018 12:27:05 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ew9F1-0005YD-P2 for bug-gnu-emacs@gnu.org; Wed, 14 Mar 2018 12:27:04 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:53843) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1ew9F1-0005Xh-MM for bug-gnu-emacs@gnu.org; Wed, 14 Mar 2018 12:27:03 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1ew9F0-0001qt-1w for bug-gnu-emacs@gnu.org; Wed, 14 Mar 2018 12:27:03 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 14 Mar 2018 16:27:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 30816 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 30816-submit@debbugs.gnu.org id=B30816.15210448217116 (code B ref 30816); Wed, 14 Mar 2018 16:27:01 +0000 Original-Received: (at 30816) by debbugs.gnu.org; 14 Mar 2018 16:27:01 +0000 Original-Received: from localhost ([127.0.0.1]:33507 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ew9Ez-0001qe-83 for submit@debbugs.gnu.org; Wed, 14 Mar 2018 12:27:01 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:56694) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ew9Ex-0001qL-4X for 30816@debbugs.gnu.org; Wed, 14 Mar 2018 12:26:59 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ew9Eo-0005TW-Ki for 30816@debbugs.gnu.org; Wed, 14 Mar 2018 12:26:53 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:57036) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ew9Eo-0005TS-Gi; Wed, 14 Mar 2018 12:26:50 -0400 Original-Received: from [176.228.60.248] (port=1390 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1ew9En-0000QO-W2; Wed, 14 Mar 2018 12:26:50 -0400 In-reply-to: (message from Xu Chunyang on Wed, 14 Mar 2018 17:58:32 +0800) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:144268 Archived-At: > From: Xu Chunyang > Date: Wed, 14 Mar 2018 17:58:32 +0800 > > > (info "(elisp) Property Search") has the following: > > -- Function: previous-property-change pos &optional object limit > This is like ‘next-property-change’, but scans back from POS > instead of forward. If the value is non-‘nil’, it is a position > ^^^^^^^^^ > less than or equal to POS; it equals POS only if LIMIT equals POS. > ^^ > > I don't understand the second sentence. What "the value" stands for? When we say "value" in the context of describing a function, we mean the value the function returns. In this case, the value returned by previous-property-change. > If it stands for LIMIT, what "it" stands for? "It" stands for the value returned by the function. the text says that the function returns the position of the previous change of the property, and that position could only be the same as the starting position POS if LIMIT is equal to POS, i.e. if LIMIT forces the function to stop at its starting position. I hope this clarifies the issue.