220 33544 article Path: news.gmane.org!.POSTED!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Catch block for multiple exceptions Date: Wed, 2 Aug 2017 22:07:00 +0300 Lines: 23 Approved: news@gmane.org Message-ID: References: <4126837.jZlGhgVnua@tjmaciei-mobl1> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: blaine.gmane.org 1501700823 5727 195.159.176.226 (2 Aug 2017 19:07:03 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 2 Aug 2017 19:07:03 +0000 (UTC) To: "ISO C++ Standard - Future Proposals" Original-X-From: std-proposals+bncBC5JHI7A7ALRBVOFRDGAKGQE46T4H2Y@isocpp.org Wed Aug 02 21:06:59 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f197.google.com ([209.85.217.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dcyyv-00019h-82 for gclcip-std-proposals@m.gmane.org; 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[2607:f8b0:400c:c08::232]) by mx.google.com with ESMTPS id 49si11433483uaj.150.2017.08.02.12.07.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Aug 2017 12:07:01 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400c:c08::232 as permitted sender) client-ip=2607:f8b0:400c:c08::232; Original-Received: by mail-ua0-x232.google.com with SMTP id f9so24914024uaf.4 for ; Wed, 02 Aug 2017 12:07:01 -0700 (PDT) X-Received: by 10.176.2.205 with SMTP id 71mr18139205uah.161.1501700821258; Wed, 02 Aug 2017 12:07:01 -0700 (PDT) Original-Received: by 10.103.103.65 with HTTP; Wed, 2 Aug 2017 12:07:00 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.b=Y4xyWidK; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400c:c08::232 as permitted sender) smtp.mailfrom=ville.voutilainen@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.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:33544 Archived-At: On 2 August 2017 at 21:47, Nicol Bolas wrote: > However, I think a small library feature could help make it less painful. > Right now, we have `current_exception`, which gives us an `exception_ptr`, > which is completely type-erased. We could give `exception_ptr` a way to > un-erase the type. After all, the implementation has to have that type > somewhere, since we can throw and re-catch it. > > So perhaps an `any_cast`-like mechanism, that returns either `nullptr` or a > pointer to the exception object. Only it should work as if it were a > `dynamic_cast`. Then, we could implement an `exception_visitor` that takes a > sequence of types and tries them, in order. The ability to do an any_cast on an exception_ptr would indeed be nice. I'll see what I can do. There's a chance that adding such a beast isn't particularly hard implementation-wise. -- 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 email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAFk2RUbmCYrr8eSKDHq6GDV-VhwPZoPM07Je6r5VPugEhrfpig%40mail.gmail.com. .