From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: =?UTF-8?Q?Andreas_R=c3=b6hler?= Newsgroups: gmane.emacs.help Subject: Re: (copy-marker nil) Date: Mon, 7 May 2018 16:20:41 +0200 Message-ID: <1e55da6a-d791-c613-ac9a-5d9bc57f840f@easy-emacs.de> References: <364c8f2d-06ab-4f81-852f-eb3bac7a0615@easy-emacs.de> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1525702679 29643 195.159.176.226 (7 May 2018 14:17:59 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 7 May 2018 14:17:59 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux i686; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 To: Help Gnu Emacs mailing list Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Mon May 07 16:17:55 2018 Return-path: Envelope-to: geh-help-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 1fFgxf-0007bh-ER for geh-help-gnu-emacs@m.gmane.org; Mon, 07 May 2018 16:17:55 +0200 Original-Received: from localhost ([::1]:46527 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fFgzm-00069k-4C for geh-help-gnu-emacs@m.gmane.org; Mon, 07 May 2018 10:20:06 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51594) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fFgzE-00069e-H4 for help-gnu-emacs@gnu.org; Mon, 07 May 2018 10:19:33 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fFgzB-0004YE-9z for help-gnu-emacs@gnu.org; Mon, 07 May 2018 10:19:32 -0400 Original-Received: from mout.kundenserver.de ([212.227.126.187]:58137) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fFgzB-0004XQ-0X for help-gnu-emacs@gnu.org; Mon, 07 May 2018 10:19:29 -0400 Original-Received: from [192.168.178.35] ([188.103.18.182]) by mrelayeu.kundenserver.de (mreue001 [212.227.15.167]) with ESMTPSA (Nemesis) id 0M2kwo-1eQcZ71bLa-00siL7 for ; Mon, 07 May 2018 16:19:27 +0200 In-Reply-To: Content-Language: en-US X-Provags-ID: V03:K1:JNbtu9melpFK7cOowmYUfv9wvWWkYC0eLPKW8SBQrdtWNdTOof/ kaREFQZhCcQvxJemxuT+WjhK4HSUETymuEuswF15qGsvy0lHAAeJvpi74gxXbTy0qI5EARM UY2vYn9xr5jTSDptOe8relomY9YF5YynBIFR0BPmWSDChFceVU2BzExhoSXb+jpgug+dK8s wy8KJCnORmnPzEjemaT5g== X-UI-Out-Filterresults: notjunk:1;V01:K0:qUQPGdH5KE8=:PYb1F6/gfDJfwr/Tuwdvfu NVviNH9M85CXgC18DzdlpmK6jQrGNI68q8nT/7DuUWTt1uwmbwSVo8w/DYckybVKRlZX033kt Tssu3VdQOhfCyOREyqBEfx21CNMATfqYqx/KOMI7CJ3ewqLoiwGxsfy7Mb0girVTMnUFJhN6+ hKsiJCCDP3zpT0Gu469w/UyJOqgP0aNOpB6erlQPvHsgt086xxdQOxYu3Y6KuGVXAzxq4WKmo nj9/LwpWgmHbhp1hBH6you8xNUaEvZiW/fS/I6cZD2OXyi+0o+9BLbYGCOj8qszhUJozSKD1W 5PZumJYR+mIN4HdAQr1j4sb3EEFEeczjT6P6YMcYCTVcjP+KioCSB1OaUizL2QiL0Q/BZJNB6 0HoPMqtZbYVeN+vCGiHN5nkO5M+uhj3xDP6xYHIOg6UXq0fdMM5SPaY1bX+d9A7ayddk5+J43 +UiGPE78My5kbXRv6n/gP/4jMue+Rkl6t57+J21DH5fpMi5AjEpDUOeo46ZFijSZ0noWN2Su8 OkINPQ5QrPIFLx27lAHq0ItDJZDtE10jImDhESuKsnlJa+2YYs4zD6iu6asrXFMYW+sOuHAH/ eaxbS4/RW/7qreOHEczQjIwsjkjxgUKG+V2j/xFDb9oDYPXtQUrkCBCXsz3/1t3ckCVQU6KMJ S6cy/EjBcKeRXiQi6UdW6SXI8sK7kYBxgcxbXrISTO9CnLW3sf31l59+n5jvqcYzuInWn4D1B UTSRRh+FVyZa51Xk X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 212.227.126.187 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:116675 Archived-At: On 07.05.2018 15:55, Noam Postavsky wrote: > On 7 May 2018 at 04:19, Andreas Röhler wrote: > >> being surprised WRT behavior of copy-marker: >> >> (setq a (copy-marker nil)) -> # >> (markerp a) -> t >> a -> # >> >> Is taking nil by copy-marker reasonable? > > For most functions, passing nil for an &optional parameter is the same > as omitting it. > > (copy-marker &optional MARKER TYPE) > [...] > If MARKER is not specified, the new marker does not point anywhere. > It's about the return value. A marker pointing nowhere, might it be considered valid? Expected such returning nil. The use-case is the end-position of some object at point. Which will not exist, if there exists no one there. A useful info maybe. Without marker, the end-position will be nil. However (setq end-position (copy-marker an-end-maybe)) makes it being something at any case.