Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!aioe.org!feeder.news-service.com!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <rosuav@gmail.com>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.032
X-Spam-Evidence: '*H*': 0.94; '*S*': 0.00; 'dictionary': 0.07; 'def': 0.13; 'am,': 0.14; 'wrote:': 0.14; 'expression,': 0.16; 'hmm.': 0.16; 'tue,': 0.20; 'header:In-Reply-To:1': 0.22; 'received:209.85.214.174': 0.23; 'received:mail- iw0-f174.google.com': 0.23; 'version': 0.25; 'subject: -- ': 0.25; 'chris': 0.27; 'message-id:@mail.gmail.com': 0.28; 'skip:( 20': 0.31; 'to:addr:python-list': 0.32; 'assignment': 0.35; 'getting': 0.36; 'else': 0.37; 'received:209.85': 0.37; 'apr': 0.38; 'received:google.com': 0.38; 'but': 0.38; 'received:209.85.214': 0.39; 'to:addr:python.org': 0.39; 'received:209': 0.39; "it's": 0.40; 'header:Received:5': 0.40; '2011': 0.62; 'legal': 0.64
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type:content-transfer-encoding; bh=DRYioHeBHdX9iXmHzEIhpeSRtBSqbLBUZB8KRlFdRj4=; b=f5Ug1P2gSK+Lt8PZPjO/LQCzacCacBI3HG3Zh2xBRDASa7JB7bipGuH3PIYiNWd5l/ yYvuSmQaeLDxL2zqSxOGdHaR2qNR2QdZTBNsBadmTGv1V6NjLBHMCj0UM33jNBSOuV3g hAWSAv3t+elrIWHYGG/512+4qvkmJGpO5ksEo=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=fvdLkcN/IZ4hGwDCPtoKVLAf9tV22nwv16fMI/hpL5fDeMSl2XH6KAi41ZBU83+PYb uS1B8Itr8FB08tqINAp62J4bOTd5quRFeKry3GiH00o91viiHpSemoM1g2G8KMWohgjL ej24WGdwaxf+bKf/URctaQhppq+fYGncMs8kg=
MIME-Version: 1.0
In-Reply-To: <BANLkTinb17D2fcgJ17OQAdP-RpYpkcXs3Q@mail.gmail.com>
References: <8abff237-5ccd-4eb6-85c8-cdc9e87520b7@bl1g2000vbb.googlegroups.com> <BANLkTi=oDios_uPK5UrMWmouhGf-4MVAuA@mail.gmail.com> <BANLkTinb17D2fcgJ17OQAdP-RpYpkcXs3Q@mail.gmail.com>
Date: Tue, 12 Apr 2011 10:51:06 +1000
Subject: Re: Feature suggestion -- return if true
From: Chris Angelico <rosuav@gmail.com>
To: python-list@python.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
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.235.1302569468.9059.python-list@python.org>
Lines: 12
NNTP-Posting-Host: 82.94.164.166
X-Trace: 1302569468 news.xs4all.nl 81475 [::ffff:82.94.164.166]:40317
X-Complaints-To: abuse@xs4all.nl
Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:3010

On Tue, Apr 12, 2011 at 10:46 AM, Chris Angelico <rosuav@gmail.com> wrote:
> def fac(n):
> =A0 =A0return cache[n] or (cache[n]=3D1 if n<=3D1 else fac(n-1)*n)

Hmm. The function-call version of dictionary assignment IS legal in an
expression, but it's getting stupid...

def fac(n):
    return cache.get(n) or (cache.__setitem__(n,1 if n<=3D1 else
fac(n-1)*n) or cache[n])

Chris Angelico