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 16:22:14 -0400 Message-ID: References: <838rd3cg7u.fsf@gnu.org> <83353bc97b.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="16025"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: 63825@debbugs.gnu.org, Eshel Yaron To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Jun 01 22:23:44 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 1q4opk-0003wu-Rk for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 01 Jun 2023 22:23:44 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q4op9-0005JW-3d; Thu, 01 Jun 2023 16:23:07 -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 1q4op4-0005It-MC for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 16:23:05 -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 1q4op4-0008Pa-Eg for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 16:23:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1q4op4-0008Sf-6v for bug-gnu-emacs@gnu.org; Thu, 01 Jun 2023 16:23:02 -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 20:23:02 +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=B63825.168565094232450 (code B ref 63825); Thu, 01 Jun 2023 20:23:02 +0000 Original-Received: (at 63825) by debbugs.gnu.org; 1 Jun 2023 20:22:22 +0000 Original-Received: from localhost ([127.0.0.1]:38485 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q4ooQ-0008RK-EY for submit@debbugs.gnu.org; Thu, 01 Jun 2023 16:22:22 -0400 Original-Received: from mxout5.mail.janestreet.com ([64.215.233.18]:38749) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1q4ooN-0008R2-5D for 63825@debbugs.gnu.org; Thu, 01 Jun 2023 16:22:21 -0400 In-Reply-To: <83353bc97b.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 01 Jun 2023 21:46:00 +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:262722 Archived-At: Eli Zaretskii writes: >> From: Eshel Yaron >> Cc: Spencer Baugh , 63825@debbugs.gnu.org >> Date: Thu, 01 Jun 2023 19:45:39 +0300 >> >> 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: >> >> --8<---------------cut here---------------start------------->8--- >> (setq-default header-line-format '(:eval nil)) >> --8<---------------cut here---------------end--------------->8--- >> >> (In Emacs master with -Q.) > > It shouldn't be hard to make this special case behave as you want. > Specifically, if the header-line-format is just a single cons cell, > and the car of that cons cell is either :eval or a symbol, and the > result of evaluation those yields nil, don't display the header line. > (I don't really like the idea of not displaying the mode line under > the same conditions.) > > Patches welcome. Ok, the easy way to achieve that is to run format-mode-line on the header-line-format and if it evaluates to "", don't display the header line. That also ignores the cases where header-line-format is multiple cons cells, all of which evaluate to nil, and other such scenarios. Is that an acceptable approach to you?