Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: Chris Angelico Newsgroups: comp.lang.python Subject: Re: Late-binding of function defaults (was Re: What is a function parameter =[] for?) Date: Sun, 22 Nov 2015 04:02:13 +1100 Lines: 14 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: news.uni-berlin.de 5PLvQ2h8nRHYVksjOd2OSgmc028Ey+yHyhovTzYoRshQ== Return-Path: 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; 'received:209.85.223': 0.03; 'cc:addr:python-list': 0.09; '"if': 0.09; '22,': 0.09; 'spelled': 0.09; 'subject: \n ': 0.15; 'callable,': 0.16; 'cc:name:python': 0.16; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'received:io': 0.16; 'received:psf.io': 0.16; 'subject:?)': 0.16; 'ugly.': 0.16; 'wrote:': 0.16; 'written,': 0.18; '2015': 0.20; 'cc:2**0': 0.20; 'cc:addr:python.org': 0.20; 'decorator': 0.22; 'am,': 0.23; 'header:In-Reply-To:1': 0.24; 'message-id:@mail.gmail.com': 0.27; "i'm": 0.30; 'probably': 0.31; 'implement': 0.32; 'wrap': 0.33; 'received:google.com': 0.35; 'could': 0.35; 'nov': 0.35; 'something': 0.35; 'but': 0.36; 'lines': 0.36; 'received:209.85': 0.36; 'subject:: ': 0.37; 'front': 0.38; 'version': 0.38; 'received:209': 0.38; 'sure': 0.39; 'along': 0.39; 'subject:-': 0.39; 'default': 0.61; 'leaving': 0.63; 'chrisa': 0.84; 'to:none': 0.91 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:cc :content-type; bh=OcjfIuRpOBXDtHTLHBsWJpzgfZFYrFfZsT9yNssqNBQ=; b=Z2y1d9nBO+M63zHoAguA+Z9VzVTtBqs9zZ5tJ5EYvhLmKZKlTLLplHHUCw4VK7sdtY yd8WUeduIe/NFvO7nJKkaghr51C4V173/WHpks0UU7s9Pgpr2ReiJCOV9O6xcLgb1avX E8XAlinxUO0QRWahehHXvvhDuQ0ThcJi0F+VUylcV3JJB8hfhbTNmbZ3kzZFCq37vaHw w6xpADL4rCwHOnlvHG5Ei6g785eWAYZJOnIfeMFF5S3qlE+e2pQSzh2O+znIPLREQO/i uUqBzCUfUIKNS2ZQfAlSWsbZqxt6pMHjxdjbdzOXH3cr6M9FFsfL0YBtFMmfK9DymmDh eSYQ== X-Received: by 10.107.16.84 with SMTP id y81mr17546913ioi.19.1448125333613; Sat, 21 Nov 2015 09:02:13 -0800 (PST) In-Reply-To: X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com comp.lang.python:99216 On Sun, Nov 22, 2015 at 2:01 AM, Ian Kelly wrote: >> and then the decorator could wrap the function. I'm not entirely sure >> I could implement it reliably, but even leaving that aside, having to >> put "lambda:" in front of everything is pretty ugly. > > Note that "lambda: []" can also be spelled "list". In that particular example, yes. I kept it in the large form to maintain the parallel with the version I was quoting. But if the decorator were to be written, it would probably be something along the lines of "if the default is callable, do the late-binding magic", so 'list' would work just fine. ChrisA