From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Spencer Baugh Newsgroups: gmane.emacs.bugs Subject: bug#63825: 29.0.90; The header line should be hidden when empty Date: Thu, 01 Jun 2023 13:37:18 -0400 Message-ID: References: <838rd3cg7u.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="18683"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Eli Zaretskii , 63825@debbugs.gnu.org To: Eshel Yaron Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Jun 01 19:38:15 2023 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q4mFb-0004eN-Ox for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 01 Jun 2023 19:38:15 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q4mFQ-0003Uc-4S; Thu, 01 Jun 2023 13:38:04 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q4mFO-0003Tt-Ha for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 13:38:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1q4mFO-0001xi-8I for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 13:38:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1q4mFO-00041y-0O for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 13:38:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Spencer Baugh Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 01 Jun 2023 17:38:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 63825 X-GNU-PR-Package: emacs Original-Received: via spool by 63825-submit@debbugs.gnu.org id=B63825.168564104715445 (code B ref 63825); Thu, 01 Jun 2023 17:38:01 +0000 Original-Received: (at 63825) by debbugs.gnu.org; 1 Jun 2023 17:37:27 +0000 Original-Received: from localhost ([127.0.0.1]:38423 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q4mEo-000413-R4 for submit@debbugs.gnu.org; Thu, 01 Jun 2023 13:37:27 -0400 Original-Received: from mxout5.mail.janestreet.com ([64.215.233.18]:38323) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q4mEl-00040m-T3 for 63825@debbugs.gnu.org; Thu, 01 Jun 2023 13:37:24 -0400 In-Reply-To: (Eshel Yaron's message of "Thu, 01 Jun 2023 19:45:39 +0300") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:262716 Archived-At: Eshel Yaron writes: > Eli Zaretskii writes: >> header-line-format supports :eval and :when, so why cannot >> which-function-mode use those to yield nil when there's nothing to >> show? > > I thought so as well, but it seems that the header line is displayed > even when the value of `header-line-format` yields nil, if it isn't > plain nil. > > So this shows an empty header line: > > (setq-default header-line-format '(:eval nil)) > > (In Emacs master with -Q.) Yes, this is what I meant. Sorry, my example was not chosen carefully. I should have chosen an example which yielded an actually empty string when processed by format-mode-line, such as '(:eval nil); (format-mode-line '(:eval nil)) evaluates to "", which I think should cause the header-line to not appear.