From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: Closures - do you understand them well? Date: Wed, 18 Jan 2023 13:23:26 +0100 Message-ID: <87pmbcxc8x.fsf@dataswamp.org> References: <87h6y5pt8k.fsf@web.de> <87bkodpqnk.fsf@web.de> <87k030tlfh.fsf@web.de> <87ilike1l8.fsf@gnu.org> <87cz8suv92.fsf@dataswamp.org> <87v8m4ytnq.fsf@dataswamp.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="6484"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:pZN8QFtNA9f6ogfxLS9dxH1uCdU= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu Jan 19 12:44:29 2023 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pITLI-0001RJ-BP for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 19 Jan 2023 12:44:28 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pITL4-00072A-Mh; Thu, 19 Jan 2023 06:44:14 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pI7V4-0006Kq-G0 for help-gnu-emacs@gnu.org; Wed, 18 Jan 2023 07:25:07 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pI7V2-0003Wb-OG for help-gnu-emacs@gnu.org; Wed, 18 Jan 2023 07:25:06 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pI7V0-0004F8-Dq for help-gnu-emacs@gnu.org; Wed, 18 Jan 2023 13:25:02 +0100 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Thu, 19 Jan 2023 06:44:13 -0500 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:142410 Archived-At: tomas wrote: >> Side question, how many 'times' are there and what, at >> least conceptually, happens in each? Figure or ascii >> diagram, anyone? > > It's turtles [1] all the way down! Since you have eval, you > are empowered to compile at run time and thus have a compile > time in there. Still, there are (at least) two phases (at > least whenever you have anything more than "just" a naive > interpreter), one where your "source" is being analysed to > find opportunities ("this variable is always bound to 3 here > [2] (or to the identity fun, or...) so we can roll that > constant into the compile product"), and the run time, where > that product is "run". > >>> Welcome to Lisp's multiple personality :-) >> >> Explain :-) :-( > > Other languages (e.g. C) have clearly distinct sub-languages > to do things at compile time (C, again, has CPP, which is > clearly distinct from C proper). In Lisp, you can use Lisp > at compile time (the language you use to transform your > source is Lisp), but at the same time, your environment is > completely different at those two phases. Some go as far as > to say that they are different languages. Typically there > are devices to control that (in Emacs Lisp > `eval-when-compile' and `eval-and-compile', I'll let more > knowledgeable folks chime in and complete that list). The byte-compiler is written in Elisp and it transforms Elisp including performing various optimization efforts know to the world of compilers, then the resulting transformed/optimized Elisp is or can be run independently. The environment are different since first it's the environment of the byte-compiler, after that it's the environment of the compiled program ... -- underground experts united https://dataswamp.org/~incal