Path: csiph.com!usenet.pasdenom.info!aioe.org!news.stack.nl!newsfeed.xs4all.nl!newsfeed4.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: UNSURE 0.238 X-Spam-Level: ** X-Spam-Evidence: '*H*': 0.65; '*S*': 0.12; 'subject:while': 0.09; 'yeah,': 0.09; 'cc:addr:python-list': 0.11; 'cc:name:python list': 0.16; 'everybody.': 0.16; 'fine.': 0.16; 'formally': 0.16; 'subject:recursion': 0.16; 'machine': 0.22; 'cc:addr:python.org': 0.22; 'creating': 0.23; 'cc:2**0': 0.24; 'header:In-Reply-To:1': 0.27; 'point': 0.28; '(like': 0.30; 'message-id:@mail.gmail.com': 0.30; 'code': 0.31; "can't": 0.35; 'received:google.com': 0.35; 'scheme': 0.36; 'done': 0.36; 'doing': 0.36; 'should': 0.36; 'two': 0.37; 'clear': 0.37; 'how': 0.40; 'everybody': 0.60; 'full': 0.61; 'challenge': 0.61; '*and*': 0.84; 'confusing': 0.84; 'effects,': 0.84; 'dynamics': 0.91; 'magical': 0.91; 'procedural': 0.91; 'received:mail-wi0-x229.google.com': 0.91; 'was:': 0.91; 'washington': 0.93 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:to :cc:content-type; bh=JBGN+epwp0oo4JDKDMT+aI4/4kOPci/vjbYbg7xpqyA=; b=cj+aSkzXq6nRHqJe2ExRJqJsTgd7FZkMBD+mTHC0jflswwlWPDK0DalJcXfgGP8VVd aM4gHZoCwUiVcWF8ajDo7oHCIKR31Qn2u70BbbhyfzmjLCJxO+YJVWLYO45AYGxT5lEk 3gXht7O1JKgw0JphmVOsRf/INcHmf3L7bJc5ydbqCRLHFQd4JJcqS4LIuAP1nXk2unSy bt0LoillqVVErSYqFUZiBonknXaSYVn+RaO5ubZcxCSlcGBGbaeYMkZ4xpEetONyfnRd ON92BKyJKfNHhZptQtVaGR5bkKj8uDkt6SfhKzWELO0FMQqg8hImFfB5i+g43bG8FEDG ujeA== MIME-Version: 1.0 X-Received: by 10.180.198.44 with SMTP id iz12mr21448226wic.32.1381186046354; Mon, 07 Oct 2013 15:47:26 -0700 (PDT) In-Reply-To: <5252F610.9040403@rece.vub.ac.be> References: <87had0axxy.fsf@dpt-info.u-strasbg.fr> <524C80B6.3010204@unistra.fr> <87li292wnt.fsf@dpt-info.u-strasbg.fr> <878uy52ea0.fsf@dpt-info.u-strasbg.fr> <5252F610.9040403@rece.vub.ac.be> Date: Mon, 7 Oct 2013 15:47:26 -0700 Subject: Re: Tail recursion to while iteration in 2 easy steps From: Mark Janssen To: Antoon Pardon Content-Type: text/plain; charset=ISO-8859-1 X-Mailman-Approved-At: Tue, 08 Oct 2013 01:28:33 +0200 Cc: Python List X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 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: 16 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1381188514 news.xs4all.nl 15908 [2001:888:2000:d::a6]:56315 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:56336 >> That's fine. My point was: you can't at the same time have full >> dynamicity *and* procedural optimizations (like tail call opt). >> Everybody should be clear about the trade-off. > > Your wrong. Full dynamics is not in contradiction with tail call > optimisation. Scheme has already done it for years. You can rebind > names to other functions in scheme and scheme still has working > tail call optimisatiosn. Yeah, and this is where two models of computation have been conflated, creating magical effects, confusing everybody. I challenge you to get down to the machine code in scheme and formally describe how it's doing both. -- MarkJ Tacoma, Washington