Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder1.enfer-du-nord.net!newsfeed.eweka.nl!eweka.nl!feeder3.eweka.nl!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!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 0.000 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'subject:Python': 0.05; '"""': 0.07; 'behave': 0.07; 'happily': 0.07; 'python': 0.08; 'decorator': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:80.91.229.12': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'received:lo.gmane.org': 0.09; 'things.': 0.12; 'def': 0.13; 'python?': 0.15; 'anymore.': 0.16; 'comma,': 0.16; 'declaration': 0.16; 'rachel': 0.16; 'string:': 0.16; "wouldn't": 0.17; 'string,': 0.18; 'this?': 0.19; 'maybe': 0.21; 'joining': 0.23; 'string': 0.24; '"the': 0.26; 'function': 0.27; '(this': 0.28; 'yield': 0.29; 'example': 0.29; 'decorators': 0.30; 'elsewhere': 0.30; 'fewer': 0.30; 'michael': 0.31; 'does': 0.32; 'wondering': 0.32; 'list': 0.32; "can't": 0.32; "isn't": 0.33; 'header:User-Agent:1': 0.33; 'header:X-Complaints-To:1': 0.33; 'there': 0.33; 'it?': 0.33; 'to:addr:python-list': 0.34; 'things': 0.34; 'example,': 0.37; 'combination': 0.37; 'but': 0.37; 'doing': 0.38; 'using': 0.38; 'thomas': 0.38; 'received:org': 0.38; 'why': 0.39; 'missing': 0.40; 'to:addr:python.org': 0.40; 'once': 0.60; 'here:': 0.66; 'said:': 0.67; 'funny': 0.76; 'subject:!!!': 0.76; 'generator,': 0.84; 'something.': 0.84 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: K.-Michael Aye Subject: Re: I love the decorator in Python!!! Date: Thu, 8 Dec 2011 12:22:27 +0100 Organization: University of Bern References: <29996186.628.1323328726122.JavaMail.geo-discussion-forums@prfb7> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Gmane-NNTP-Posting-Host: rain.gmane.org User-Agent: Unison/2.1.5 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: 53 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1323343364 news.xs4all.nl 6881 [2001:888:2000:d::a6]:43456 X-Complaints-To: abuse@xs4all.nl Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:16821 On 2011-12-08 08:59:26 +0000, Thomas Rachel said: > Am 08.12.2011 08:18 schrieb 88888 Dihedral: >> I use the @ decorator to behave exactly like a c macro that >> does have fewer side effects. >> >> I am wondering is there other interesting methods to do the >> jobs in Python? > > In combination with a generator, you can do many funny things. > > > For example, you can build up a string: > > def mkstring(f): > """Turns a string generator into a string, > joining with ", ". > """ > return ", ".join(f()) > > def create_answer(): > @mkstring > def people(): > yield "Anna" > yield "John" > yield "Theo" > > return "The following people were here: " + people > > > Many other things are thinkable... > > > Thomas I am still perplexed about decorators though, am happily using Python for many years without them, but maybe i am missing something? For example in the above case, if I want the names attached to each other with a comma, why wouldn't I just create a function doing exactly this? Why would I first write a single name generator and then decorate it so that I never can get single names anymore (this is the case, isn't it? Once decorated, I can not get the original behaviour of the function anymore. So, above, why not def mkstring(mylist): with the same function declaration and then just call it with a list of names that I generate elsewhere in my program? I just can't identify the use-case for decorators, but as I said, maybe I am missing something. Michael