Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <python-python-list@m.gmane.org>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.003
X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'function,': 0.07; 'python': 0.09; 'concurrent': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'stackless': 0.09; 'switches': 0.09; "(i'm": 0.16; 'jumping': 0.16; 'message-id:@dough.gmane.org': 0.16; 'modules,': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'threads': 0.16; 'wrote:': 0.17; 'examples': 0.18; 'memory': 0.18; 'supposed': 0.21; 'example': 0.23; 'programming': 0.23; 'allows': 0.25; 'header:In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'header:X-Complaints-To:1': 0.28; 'i/o': 0.29; 'function': 0.30; 'could': 0.32; 'to:addr :python-list': 0.33; 'version': 0.34; "can't": 0.34; 'subject:?': 0.35; 'there': 0.35; 'received:org': 0.36; 'but': 0.36; 'url:org': 0.36; 'uses': 0.37; 'why': 0.37; 'subject:: ': 0.38; 'easier': 0.38; 'some': 0.38; 'url:en': 0.38; 'to:addr:python.org': 0.39; 'space': 0.39; 'called': 0.39; 'header:Received:5': 0.40; 'address': 0.60; 'subject:, ': 0.61; 'url:index': 0.61; 'back': 0.62; 'lightweight': 0.84; 'received:89': 0.86; 'officially': 0.91
X-Injected-Via-Gmane: http://gmane.org/
To: python-list@python.org
From: Damjan <gdamjan@gmail.com>
Subject: Re: why greenlet, gevent or the stackless are needed?
Date: Sat, 07 Jul 2012 17:38:53 +0200
References: <456501fb-af2d-4741-9b73-33c65d7f0aa8@t1g2000pbl.googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Gmane-NNTP-Posting-Host: 89.205.110.217
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:13.0) Gecko/20120616 Thunderbird/13.0.1
In-Reply-To: <456501fb-af2d-4741-9b73-33c65d7f0aa8@t1g2000pbl.googlegroups.com>
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.1893.1341675491.4697.python-list@python.org>
Lines: 32
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1341675491 news.xs4all.nl 6953 [2001:888:2000:d::a6]:35090
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:25023

On 07.07.2012 09:09, self.python wrote:
> (I'm very new to this coroutine part
> so It's not supposed to attack these modules,
> just I don't know the differences)
>
> atfer version 2.5, python officially support coroutine with yield.
> and then, why greenlet, gevent, Stackless python are still useful?
>
> it there somthing that "yield" can't do
> or just it is easier or powerful?

The greenlet site has some very simple examples what it can provide.
For example jumping from one function in another, and back

http://greenlet.readthedocs.org/en/latest/index.html


Gevent then uses greenlet to do lightweight "processes" (greenlets) that 
are I/O scheduled. This allows for a simple model of programming that 
scales to a large number of concurrent connections. You could do that 
with threads but you can't start as many threads as greenlets, since 
they have a much larger memory address space footprint.

There's one function, called the gevent hub, that waits for any I/O 
event and then switches to the function that "blocked" on that I/O.




-- 
damjan