Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:32425 Return-Path: Mailing-List: contact internals-help@lists.php.net; run by ezmlm Delivered-To: mailing list internals@lists.php.net Received: (qmail 9190 invoked by uid 1010); 23 Sep 2007 15:46:54 -0000 Delivered-To: ezmlm-scan-internals@lists.php.net Delivered-To: ezmlm-internals@lists.php.net Received: (qmail 9175 invoked from network); 23 Sep 2007 15:46:54 -0000 Received: from unknown (HELO lists.php.net) (127.0.0.1) by localhost with SMTP; 23 Sep 2007 15:46:54 -0000 Authentication-Results: pb1.pair.com header.from=paul.biggar@gmail.com; sender-id=pass; domainkeys=bad Authentication-Results: pb1.pair.com smtp.mail=paul.biggar@gmail.com; spf=pass; sender-id=pass Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.146.177 as permitted sender) DomainKey-Status: bad X-DomainKeys: Ecelerity dk_validate implementing draft-delany-domainkeys-base-01 X-PHP-List-Original-Sender: paul.biggar@gmail.com X-Host-Fingerprint: 209.85.146.177 wa-out-1112.google.com Received: from [209.85.146.177] ([209.85.146.177:10298] helo=wa-out-1112.google.com) by pb1.pair.com (ecelerity 2.1.1.9-wez r(12769M)) with ESMTP id F0/51-30687-D6A86F64 for ; Sun, 23 Sep 2007 11:46:54 -0400 Received: by wa-out-1112.google.com with SMTP id l24so1819423waf for ; Sun, 23 Sep 2007 08:46:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; bh=G6bcnYbsvlOU72+803MD57gk/ljY2h/EGQCMg3irAeA=; b=r0p48dUPwE/Duiz4rxoVp8OXYmwFpmXtL4a8OSSbs84iqOKx+GFpwu1KcmrG3ik8tj4665fhAyfUKw2w6D1ohh5b8YcLPu08+rSLKq/iJ7k07cer6AEOipXNMEczeSWEm15rtV9YWRD0XEhgFWS4r4KK8WIMDB5z5Hz5R3FiH5U= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=tL7xTlDmN9Rxa42UcdZXoF1LMIF7sGVA0wk2eDUvCVbvnDli/L+RS9u5UbFp13Ro5IvSM7xbLOCNY5XTvJ1aDUrPWLiictSC4XtE3iinNhLQ7OEseIzDb32XJUzl5DQWX1kXC3QYzDxaqHlwyJEhPEJkjbXCQ7EGDKZbx6d2TV8= Received: by 10.115.77.1 with SMTP id e1mr160750wal.1190562410092; Sun, 23 Sep 2007 08:46:50 -0700 (PDT) Received: by 10.114.130.7 with HTTP; Sun, 23 Sep 2007 08:46:45 -0700 (PDT) Message-ID: Date: Sun, 23 Sep 2007 16:46:45 +0100 To: internals@lists.php.net MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline Subject: Compiled variables and backpatching From: paul.biggar@gmail.com ("Paul Biggar") Hi, I'd be very interested to have an overview of compiled variable and backpatching within the interpreter. I can find plenty of emails and code that refers to the two topics, but none that defines them. If there is an overview somewhere, could somebody point me to it? If not, I have a few questions. Answers of any length are appreciated. What is a compiled variable? How does it differ from a non-compiled-variable? Why were they introduced? I presume that this is for performance - what performance impact do they have? What is backpatching? Is it related to compiled variables, or are they different concepts? Why was backpatching necessary? Is this performance related, and what performance impact does backpatching have? Thanks in advance, Paul -- Paul Biggar paul.biggar@gmail.com