Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.freenet.ag!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!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 0.001 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'exception': 0.03; 'dev': 0.07; 'python': 0.09; '16-bit': 0.09; 'exception,': 0.09; 'regression': 0.09; 'sure,': 0.09; 'thrown': 0.09; 'unexpectedly': 0.09; "wouldn't": 0.11; 'subject:python': 0.11; 'cases': 0.15; '3.2.': 0.16; 'buggy': 0.16; 'efficiency.': 0.16; 'encountered,': 0.16; 'from:addr:mrabarnett.plus.com': 0.16; 'from:addr:python': 0.16; 'from:name:mrab': 0.16; 'graceful': 0.16; 'incomplete': 0.16; 'message-id:@mrabarnett.plus.com': 0.16; 'pairs': 0.16; 'received:84.93': 0.16; 'received:84.93.230': 0.16; 'statement.': 0.16; 'subject:3.3': 0.16; 'subject:String': 0.16; 'thread.': 0.16; 'utterly': 0.16; 'wed,': 0.16; 'string': 0.17; 'wrote:': 0.17; 'bytes': 0.17; 'string,': 0.17; 'thu,': 0.17; 'unicode': 0.17; '>>>': 0.18; 'trying': 0.21; '3.2': 0.22; 'assumes': 0.22; "i'd": 0.22; 'script': 0.24; 'header:In-Reply-To:1': 0.25; 'header :User-Agent:1': 0.26; 'common': 0.26; 'am,': 0.27; "doesn't": 0.28; 'chris': 0.28; 'factor': 0.29; 'character': 0.29; 'that.': 0.30; 'sense': 0.31; 'code': 0.31; 'received:84': 0.32; 'support,': 0.32; 'switch': 0.32; 'builds': 0.33; 'skip:j 20': 0.33; 'to:addr:python-list': 0.33; 'wrong': 0.34; 'compared': 0.35; 'pm,': 0.35; 'there': 0.35; 'but': 0.36; 'characters': 0.36; 'useful': 0.36; 'should': 0.36; 'does': 0.37; 'being': 0.37; 'rather': 0.37; 'subject:: ': 0.38; 'mean': 0.38; 'instead': 0.39; 'performance': 0.39; 'to:addr:python.org': 0.39; 'received:192': 0.39; 'build': 0.39; 'space': 0.39; 'received:192.168': 0.40; 'think': 0.40; 'skip:u 10': 0.60; 'wide': 0.62; 'is.': 0.62; 'between': 0.63; 'more': 0.63; 'replying': 0.64; 'making': 0.64; 'readers': 0.65; 'theoretical': 0.65; 'unnecessary': 0.65; 'subject': 0.66; 'hours': 0.66; 'talking': 0.66; 'header:Reply- To:1': 0.68; 'believe': 0.69; 'reply-to:no real name:2**0': 0.72; '2013': 0.84; 'choices:': 0.84; 'fourth': 0.84; 'reply- to:addr:python.org': 0.84; 'inefficient': 0.91; 'rusi': 0.91 X-CM-Score: 0.00 X-CNFS-Analysis: v=2.0 cv=HO4d4PRv c=1 sm=1 a=0nF1XD0wxitMEM03M9B4ZQ==:17 a=B68SgI_Jlq8A:10 a=66EW70UnfMgA:10 a=ihvODaAuJD4A:10 a=OUOv7kDek9cA:10 a=8nJEP1OIZ-IA:10 a=EBOSESyhAAAA:8 a=8AHkEIZyAAAA:8 a=INtUpLY97UEA:10 a=pGLkceISAAAA:8 a=ozpLwd3uvzrZLi9KGYUA:9 a=wPNLvfGTeEIA:10 a=MSl-tDqOz04A:10 a=0nF1XD0wxitMEM03M9B4ZQ==:117 X-AUTH: mrabarnett:2500 Date: Thu, 14 Mar 2013 00:52:08 +0000 From: MRAB User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 MIME-Version: 1.0 To: python-list@python.org Subject: Re: String performance regression from python 3.2 to 3.3 References: <23a42297-9262-4ace-87ad-138999b1ddd6@z3g2000vbg.googlegroups.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: python-list@python.org 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: 44 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1363222327 news.xs4all.nl 6877 [2001:888:2000:d::a6]:52241 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:41203 On 13/03/2013 23:43, Chris Angelico wrote: > On Thu, Mar 14, 2013 at 3:49 AM, rusi wrote: >> On Mar 13, 3:59 pm, Chris Angelico wrote: >>> On Wed, Mar 13, 2013 at 9:11 PM, rusi wrote: >>> > Uhhh.. >>> > Making the subject line useful for all readers >>> >>> I should have read this one before replying in the other thread. >>> >>> jmf, I'd like to see evidence that there has been a performance >>> regression compared against a wide build of Python 3.2. You still have >>> never answered this fundamental, that the narrow builds of Python are >>> *BUGGY* in the same way that JavaScript/ECMAScript is. And believe you >>> me, the utterly unnecessary hassles I have had to deal with when >>> permitting user-provided .js code to script my engine have wasted >>> rather more dev hours than you would believe - there are rather a lot >>> of stupid edge cases to deal with. >> >> This assumes that there are only three choices: >> - narrow build that is buggy (surrogate pairs for astral characters) >> - wide build that is 4-fold space inefficient for wide variety of >> common (ASCII) use-cases >> - flexible string engine that chooses a small tradeoff of space >> efficiency over time efficiency. >> >> There is a fourth choice: narrow build that chooses to be partial over >> being buggy. ie when an astral character is encountered, an exception >> is thrown rather than trying to fudge it into a 16-bit >> representation. > > As a simple factual matter, narrow builds of Python 3.2 don't do that. > So it doesn't factor into my original statement. But if you're talking > about a proposal for 3.4, then sure, that's a theoretical possibility. > It wouldn't be "buggy" in the sense of "string indexing/slicing > unexpectedly does the wrong thing", but it would still be incomplete > Unicode support, and I don't think people would appreciate it. Much > better to have graceful degradation: if there are non-BMP characters > in the string, then instead of throwing an exception, it just makes > the string wider. > [snip] Do you mean that instead of switching between 1/2/4 bytes per codepoint it would switch between 2/4 bytes per codepoint?