220 14692 <99891ca2-7529-4d6b-8754-c6298ac8d334@isocpp.org> article Path: news.gmane.org!not-for-mail From: Jeremy Maitin-Shepard Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Modules with lazy symbol resolution Date: Fri, 21 Nov 2014 23:51:18 -0800 (PST) Lines: 35 Approved: news@gmane.org Message-ID: <99891ca2-7529-4d6b-8754-c6298ac8d334@isocpp.org> References: <3384057.c619ZPUSbM@tjmaciei-mobl4> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_199_1050926665.1416642678990" X-Trace: ger.gmane.org 1416642692 30055 80.91.229.3 (22 Nov 2014 07:51:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 22 Nov 2014 07:51:32 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCYZZ4E5WQCRB6EAYGRQKGQEOJ7MNXQ@isocpp.org Sat Nov 22 08:51:26 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ie0-f198.google.com ([209.85.223.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xs5TV-0007r6-RP for gclcip-std-proposals@m.gmane.org; Sat, 22 Nov 2014 08:51:22 +0100 Original-Received: by mail-ie0-f198.google.com with SMTP id y20sf29416962ier.9 for ; Fri, 21 Nov 2014 23:51:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:content-type:x-original-sender:reply-to :precedence:mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=bTHrGtmtu94Nx7OwBw4zEBOcUQl0WIUpT8yIW44H7Dk=; b=kPp64+s67ZH8+5F+/ej1aw26wlP7KR5IjM/ZktJlyDng9MW3D4nlu7yDf6ZNhDc+21 zG2xqXMaeCe5bu12mjIp0p9aG6EIxZ2sbeO1Gb0pyC5tMd1Q7wVSP2jcKgiIRG1ipK/L lD7lN73LENASVQnbisXmEDjjLwdMvheQ+0hhEF8LXqU4QfTJHYpAt50iRAG8IBd9V+sJ gz+zRCCl2Z+EC+3Uufq5BHjXRXBnYJU8B2JVGAplcnWODCecqWbcYqhpBYyBT6nVzUrM cXggWJQR8wyTcKXNhGUslo3KR0BKPCN2J61Ky90+n5WgqjuTYeGV04g73EFqK/wQo9NL uUXQ== X-Gm-Message-State: ALoCoQmIVwDjd1vuEVO18T4WQSehlUEza13hxKutYJhsKnfb4DvPgKzHH4wwbnBTkeP6XSMzu1Ap X-Received: by 10.182.168.114 with SMTP id zv18mr8203139obb.23.1416642680642; Fri, 21 Nov 2014 23:51:20 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.142.66 with SMTP id ru2ls155354igb.43.canary; Fri, 21 Nov 2014 23:51:20 -0800 (PST) X-Received: by 10.50.33.39 with SMTP id o7mr29639igi.14.1416642680143; Fri, 21 Nov 2014 23:51:20 -0800 (PST) In-Reply-To: X-Original-Sender: jeremy@jeremyms.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:14692 Archived-At: ------=_Part_199_1050926665.1416642678990 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Even parsing C++ without knowing type information isn't possible, though th= is could be worked around by adding typename and template as needed to disa= mbiguate. Compiling, or even instantiating templates, most certainly would= require complete information. Therefore what you are suggesting could in = principle be supported I think with only minimal language changes by separa= ting the parsing step from the compilation step. Parsing of a module would= produce some efficient binary representation of it, but would not generate= any machine code, and would not depend on the imported modules already bei= ng parsed. The compilation step would depend on the parsing but not the co= mpilation of all imported modules. The cost is that every imported type or= template would have to be annotated as such using the typename and templat= e keywords as if they were dependent names in a template. Whether this two step procedure would actually be faster in practice is unc= lear. Also everything I said ignores the fact that clang allows modules to= export preprocessor macros. To handle that we would need a 3 step procedu= re. --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. ------=_Part_199_1050926665.1416642678990-- .