From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Barry Margolin Newsgroups: gmane.emacs.help Subject: Re: What does "lacks a prefix" mean? Date: Fri, 10 Jul 2015 10:42:19 -0400 Organization: A noiseless patient Spider Message-ID: References: <1e0ad02f-ca3e-495c-bb85-61f77090d31d@googlegroups.com> <87bnfmqzn2.fsf@kuiper.lan.informatimago.com> <87io9ui67a.fsf@nl106-137-147.student.uu.se> NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1436539538 13049 80.91.229.3 (10 Jul 2015 14:45:38 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 10 Jul 2015 14:45:38 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri Jul 10 16:45:30 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZDZYP-0003pU-1E for geh-help-gnu-emacs@m.gmane.org; Fri, 10 Jul 2015 16:45:29 +0200 Original-Received: from localhost ([::1]:44922 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDZYO-0004qz-G8 for geh-help-gnu-emacs@m.gmane.org; Fri, 10 Jul 2015 10:45:28 -0400 Original-Path: usenet.stanford.edu!news.kjsl.com!feeder.erje.net!1.eu.feeder.erje.net!weretis.net!feeder4.news.weretis.net!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!barmar.motzarella.org!.POSTED!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 38 Injection-Info: barmar.motzarella.org; posting-host="2be9e9f5dd9af768b8861af71b85fc28"; logging-data="15889"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+9hOJENPvBKrZL1DZHHf5B" User-Agent: MT-NewsWatcher/3.5.3b3 (Intel Mac OS X) Cancel-Lock: sha1:J70yxhYKonWiB7o/e72VhgWUemU= Original-Xref: usenet.stanford.edu gnu.emacs.help:213292 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:105579 Archived-At: In article , Drew Adams wrote: > > > And non-parallelizable theoretically :) > > > > Regular let isn't parallelizable. It specifies that the value > > expressions are evaluated in order. > > > > The only difference between the two is the environment within which > > later expressions are evaluated. > > FWIW, Common Lisp specifies that "let performs the bindings > in parallel and let* does them sequentially." It specifies that the bindings are done in parallel, but evaluation of the initialization forms is sequential. From http://www.lispworks.com/documentation/HyperSpec/Body/s_let_l.htm#let "LET ... first evaluates the expressions init-form-1, init-form-2, and so on, in that order, saving the resulting values. Then all of the variables varj are bound to the corresponding values" whereas "LET* ... first evaluates the expression init-form-1, then binds the variable var1 to that value; then it evaluates init-form-2 and binds var2, and so on" If the forms have no side effects, LET can indeed execute them in parallel, since there's no way to tell the difference. LET* can also do that for any initialization expressions that don't refer back to earlier variables and have no side effects. -- Barry Margolin, barmar@alum.mit.edu Arlington, MA *** PLEASE post questions in newsgroups, not directly to me ***