From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Lennart Borgman (gmail)" Newsgroups: gmane.emacs.devel Subject: Re: Explain syntax-ppss-stats please Date: Sun, 06 Apr 2008 03:25:17 +0200 Message-ID: <47F8267D.2060104@gmail.com> References: <47F79FFA.2000806@gmail.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1207445137 27240 80.91.229.12 (6 Apr 2008 01:25:37 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 6 Apr 2008 01:25:37 +0000 (UTC) Cc: Emacs Devel To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sun Apr 06 03:26:09 2008 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1JiJe3-0004ut-Nh for ged-emacs-devel@m.gmane.org; Sun, 06 Apr 2008 03:26:08 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JiJdQ-0003Lf-Ok for ged-emacs-devel@m.gmane.org; Sat, 05 Apr 2008 21:25:28 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JiJdN-0003La-Cq for emacs-devel@gnu.org; Sat, 05 Apr 2008 21:25:25 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JiJdL-0003LN-01 for emacs-devel@gnu.org; Sat, 05 Apr 2008 21:25:24 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JiJdK-0003LK-R1 for emacs-devel@gnu.org; Sat, 05 Apr 2008 21:25:22 -0400 Original-Received: from ch-smtp01.sth.basefarm.net ([80.76.149.212]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1JiJdK-00075p-8M for emacs-devel@gnu.org; Sat, 05 Apr 2008 21:25:22 -0400 Original-Received: from c83-254-150-27.bredband.comhem.se ([83.254.150.27]:64365 helo=[127.0.0.1]) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.68) (envelope-from ) id 1JiJdI-0005kt-5d; Sun, 06 Apr 2008 03:25:20 +0200 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071031 Thunderbird/2.0.0.9 Mnenhy/0.7.5.666 In-Reply-To: X-Antivirus: avast! (VPS 080405-1, 2008-04-06), Outbound message X-Antivirus-Status: Clean X-Originating-IP: 83.254.150.27 X-Scan-Result: No virus found in message 1JiJdI-0005kt-5d. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1JiJdI-0005kt-5d 61f748a0deaa4d9de09b8e5d256bed22 X-detected-kernel: by monty-python.gnu.org: Linux 2.6? (barebone, rare!) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:94462 Archived-At: Stefan Monnier wrote: >> I do not understand the use of syntax-ppss-stats at all. Where is it used? >> (I can only see that the 5:th element is read.) How does it work? > > Only the 5th element is really used. The rest was added there during > development to tune the algorithm. It could be removed. Thanks. I still believe too much in magic. I thought something strange was going on somewhere behind the scenes. Maybe this could be told in the code and the lines changing the other elements commented out? > As for the 5th element it's used to keep track of the average size of > a "defun", so as to know whether to use the closest cache location, or > to try and find a closer location with syntax-begin-function: if the > closest cache location is 100KB earlier and syntax-begin-function > usually finds a safe point within 10KB, we're better off calling > syntax-begin-function (when tho it'll typically take a while itself) > than running parse-partial-sexp on the 100KB. But OTOH if > syntax-begin-function usually needs to look back 200KB to find a safe > spot, then just the call to syntax-begin-function might take us longer > than just running parse-partial-sexp on the 100KB. Thanks, this was helpful.