Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!selfless.tophat.at!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.010 X-Spam-Evidence: '*H*': 0.98; '*S*': 0.00; 'distinction': 0.07; 'rest,': 0.07; 'terry': 0.07; 'python': 0.08; 'defined,': 0.09; 'tracker': 0.09; 'wrote:': 0.15; '2:28': 0.16; 'asking.': 0.16; 'caching': 0.16; 'reedy': 0.16; '\xa0no': 0.16; 'cc:addr:python- list': 0.16; 'pm,': 0.16; 'that?': 0.19; 'language': 0.20; 'cc:2**0': 0.21; 'cc:no real name:2**0': 0.22; 'discussion': 0.22; 'header:In-Reply-To:1': 0.22; 'code.': 0.22; 'trying': 0.23; 'pieces': 0.23; 'code': 0.24; 'modules': 0.25; 'statement': 0.25; 'function': 0.26; 'url:mailman': 0.27; 'objects': 0.28; 'sat,': 0.28; 'message-id:@mail.gmail.com': 0.28; 'compile': 0.29; 'object': 0.30; 'cc:addr:python.org': 0.30; 'definition': 0.30; 'module': 0.30; 'blocks': 0.30; 'modules,': 0.30; 'objects.': 0.30; 'subject:?': 0.31; 'url:listinfo': 0.32; 'pure': 0.32; 'actually': 0.33; 'there': 0.34; 'etc.)': 0.34; 'compilation': 0.35; 'do?': 0.35; 'module.': 0.35; 'subject:What': 0.35; 'file': 0.36; 'url:python': 0.37; 'issue': 0.37; 'but': 0.37; 'received:google.com': 0.38; 'received:209.85': 0.38; 'url:org': 0.38; 'subject:: ': 0.38; 'eric': 0.38; 'execution': 0.38; 'put': 0.38; 'case,': 0.38; 'case': 0.39; '[1]': 0.39; 'got': 0.39; 'received:209': 0.40; 'where': 0.40; 'happen': 0.62; 'body': 0.63; 'details': 0.65; 'received:209.85.215.174': 0.67; 'received:mail- ey0-f174.google.com': 0.67; 'special': 0.67; 'execution.': 0.84; 'phases': 0.84; 'special.': 0.84; 'snow': 0.91 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=PWSndoFKgGS4AXJAcvhDRIB77TQn5nBZb2XPlJOtWLo=; b=m3SdEBU5O2mXIefFbVyOD67yMDoRsMQESW40mCPTCOfqM+e9x8Zno3RhPKqUAMF482 svM1hB2HI1MPeq7NtQ0bC7MsFAwwhYKT279Kpf6zxSxKo/p5rGXpBZNUTYEAnOTy1yG1 ujPq9XwJ5BNLWb9aSr59g7NR3xA+ZrY/Xg6D4= MIME-Version: 1.0 In-Reply-To: References: Date: Sat, 9 Jul 2011 19:10:55 -0600 Subject: Re: What makes functions special? From: Eric Snow To: Terry Reedy Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: python-list@python.org X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 50 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1310260259 news.xs4all.nl 21888 [2001:888:2000:d::a6]:48134 X-Complaints-To: abuse@xs4all.nl Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:9127 On Sat, Jul 9, 2011 at 6:21 PM, Terry Reedy wrote: > On 7/9/2011 2:28 PM, Eric Snow wrote: >> >> A tracker issue [1] recently got me thinking about what makes >> functions special. =A0The discussion there was regarding the distinction >> between compile time (generation of .pyc files for modules and >> execution of code blocks), [function] definition time, and [function] >> execution time. =A0Definition time actually happens during compile time, > > Not true. For main modules, execution of each statement immediately follo= ws > compilation, but not for other modules, where compilation and caching of > code objects may happen years before the function object is created. > So for non-main modules the function definition happens during module compilation, and for all other code blocks (__main__, exec, etc.) it happens during execution of the code block? >> Functions are a special case in Python for providing a more optimized >> execution of a code block in pure Python code. =A0And how is that? =A0Wh= en >> the function is defined, a code object is generated for the function >> body along with a few "static" details that will be used during >> execution. =A0No other objects have code objects. =A0No other objects in >> Python have this special optimization. > > A .pyc file is a serialized code object for a module. > I hadn't thought of it like that. Nice insight. In that case, do [non-main] module definition and execution time have the same logical separation as function phases do? > As for the rest, I am not sure what you are asking. > Yeah, I have a real knack for communicating. :) Mostly I am just trying to put together more pieces of the Python puzzle. In this case I was trying to find out if the optimized execution of code objects for functions is a part of the language or just an implementation detail. -eric > Terry Reedy > > -- > http://mail.python.org/mailman/listinfo/python-list >