From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Will Monroe Newsgroups: gmane.emacs.help Subject: Re: Advice on troubleshooting function to "unscroll" Date: Sun, 25 Jan 2015 16:56:14 -0600 Message-ID: <54C5748E.4060605@gmail.com> References: <54C5577D.4030700@gmail.com> <871tmih6w0.fsf@wmi.amu.edu.pl> <54C56827.6030802@gmail.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1422226596 20589 80.91.229.3 (25 Jan 2015 22:56:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 25 Jan 2015 22:56:36 +0000 (UTC) To: Drew Adams , help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Jan 25 23:56:36 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YFW6b-0006tl-2l for geh-help-gnu-emacs@m.gmane.org; Sun, 25 Jan 2015 23:56:33 +0100 Original-Received: from localhost ([::1]:39238 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YFW6a-0000XV-H7 for geh-help-gnu-emacs@m.gmane.org; Sun, 25 Jan 2015 17:56:32 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:33186) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YFW6O-0000XQ-MN for help-gnu-emacs@gnu.org; Sun, 25 Jan 2015 17:56:21 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YFW6J-0003QF-RH for help-gnu-emacs@gnu.org; Sun, 25 Jan 2015 17:56:20 -0500 Original-Received: from mail-oi0-x236.google.com ([2607:f8b0:4003:c06::236]:60784) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YFW6J-0003Q3-MM for help-gnu-emacs@gnu.org; Sun, 25 Jan 2015 17:56:15 -0500 Original-Received: by mail-oi0-f54.google.com with SMTP id v63so4819070oia.13 for ; Sun, 25 Jan 2015 14:56:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=B6YEYqoLpqso30+olXpI6CrJMjhd9mtyll8Irjrgr2Q=; b=P0afUJ8LItkd9xU1pSxHOA1trCOx3bFDVH6V7vHqdwmpftbw5KwPmQP+iP5AIqk8Ox xN6XXxuSmHBfPPg4Vl2pmu2ji0pVbeb/SbDGKyzBC+/dTow13uCe0Kru8LxOgD7nKwCA +rJojlNXrtUq/HmHiITAeG0Sk2Z1ltVzQoj5twLtttRR1lBFDgYwVcmPXbTxL8mutDS1 soK+dJZPJ9BGvsQDk+gu06ueJNbsAacuaqEZ66ErpvQzK5SEgf6FwLrmjvsCAoktCcGd 6V4gzbHkH/m1y895r5jskEXPQ3p3Md+0LM9Yl1iW0VUtTjDO7Bu7cXDnHxioXe7F4G/e 4jFw== X-Received: by 10.182.148.98 with SMTP id tr2mr11262200obb.28.1422226575157; Sun, 25 Jan 2015 14:56:15 -0800 (PST) Original-Received: from [10.70.17.167] (wsip-66-210-63-210.br.no.cox.net. [66.210.63.210]) by mx.google.com with ESMTPSA id x21sm4338937oix.24.2015.01.25.14.56.14 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 25 Jan 2015 14:56:14 -0800 (PST) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 In-Reply-To: X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2607:f8b0:4003:c06::236 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:102262 Archived-At: Drew, Thank you for this detailed response. On 01/25/2015 04:45 PM, Drew Adams wrote: >> the "problem" was that C-v was bound to another (older?) function. > > The command `scroll-up' is indeed older, and it is still usable. > It is, in fact, the core of the `scroll-up-command' implementation. > > (In Emacs, it is often the case that you can use a command > non-interactively, though this is sometimes explicitly not > recommended for certain commands.) > > `scroll-up-command' was added in Emacs 24.1, to (a) retain the > `scroll-up' behavior as a separate function, and yet (b) provide > additional behavior when you scroll interactively, in particular > the handling of the new (in 24.1) option `scroll-error-top-bottom'. Interesting. Given what the author's assumptions of how 'scroll-up' should work and how the newer 'scroll-up-command' seems to share some, but not all, of that functionality, it would probably be interesting to see where they differ. I may not be expressing this clearly, but you've helped to clarify the question I want to answer to be: "why did scroll-up-command work where the still useful but not appropriate scroll-up did not?" > >> I've hesitated from diving into Edebug because there was no >> "error" as such. That is, the code "worked" it just didn't do >> what I intended. > > Using the debugger (and debugging generally) is not necessarily > about finding why Emacs raises a particular error. (That is the > particular use of variable `debug-on-error': enter the debugger > to show a backtrace when an error is raised.) > > In addition to Edebug, there is the regular Emacs debugger, aka > `debug'. Some of us prefer to use that. Others prefer to use > it in some cases but `edebug' in other cases. > > Keep in mind too that any debugger does not necessarily tell you > everything that goes on, and its representation of what happens > with debugging turned off is not flawless. In particular, this > is because using the debugger itself changes what Emacs does. > (Think of the debugger's buffer display and its handling of > input events, for example.) > > The regular debugger is what you get with `debug-on-entry' and > by inserting calls to `(debug)' in code to serve more or less as > breakpoints. See `C-h f debug' for information about evaluating > and displaying the results of sexps (cdr ARGS) upon entry into > the debugger. > This is very helpful stuff to consider as I begin to think about what I want to accomplish when using Edebug or debugger. And if I'm being honest about why I did not go to Edebug it's because I was anticipating great difficulty reading the backtrace statements. I thought my problem might be compounded by a more general illiteracy in that regard... Thanks again, Drew. A really helpful answer! Will