220 33539 article Path: news.gmane.org!.POSTED!not-for-mail From: Ricardo Fabiano de Andrade Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Catch block for multiple exceptions Date: Wed, 2 Aug 2017 13:05:30 -0500 Lines: 123 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: multipart/alternative; boundary="001a114eccbc06e71a0555c91c88" X-Trace: blaine.gmane.org 1501697132 5758 195.159.176.226 (2 Aug 2017 18:05:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 2 Aug 2017 18:05:32 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCJN7V7TRQMBB25IRDGAKGQEGTGECII@isocpp.org Wed Aug 02 20:05:27 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pf0-f200.google.com ([209.85.192.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dcy1O-00018y-Iz for gclcip-std-proposals@m.gmane.org; Wed, 02 Aug 2017 20:05:26 +0200 Original-Received: by mail-pf0-f200.google.com with SMTP id j83sf52994855pfe.10 for ; Wed, 02 Aug 2017 11:05:32 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1501697132; cv=pass; d=google.com; s=arc-20160816; b=Q22JdmTF3XZ4/+RQ/yM859sQpfz9Ut5bxcu8XQE26p3mLd7ZhGB3HvjsX/AkHsP0Q8 1shT+MFfwE5u3nCWw7b7hAZuwYX8Lve6QUUyDgKnHWjgVjvtPwoMgYALgEua6dKWENnc lvxGhNv+Zh/Gb6ZLd6Rc2Da4RPftMXWMuaf8cPgaM4b5UaV6tNAAY03IbHfKO+E282yM e614cj3zX89VKrDPltClnOXqQ9SPWvwFWxiyJQxmW/yyi8RoptcRMUB0e0ZkB9IrHSX5 tkZYKVxzcIy8yv/Us6ViEacJy4BalXXvVsKms6TWOCtBCA8iwHpbpeg5XkhXdZFglzt2 ITRw== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:reply-to:to:subject:message-id:date :from:references:in-reply-to:mime-version:arc-authentication-results :arc-message-signature:dkim-signature:arc-authentication-results; bh=ND1pzuAWdfYFsIHO2lAX2KuI7PzYPWqG99CJgXWtM/c=; b=EBKxUKRv5AfFSn1zEx1iRB8WXk6wc6W7L2Gno539j6Rgt1aFUWQg90utdKjivTbcix efR8FNATblFXz/nbyYA19PbKYqr1X+AW04ggCtR2YnL7Rf2OpXOEQ+y7Fc/Lz1EC3fp0 4wzsp5e/riiirEqLUKHHGHx2DDOqic0lrOmAH1+dKlML04izZ0fOli3GKHwIkG5CdeiI YkzMymBl4NpyrXLz5iswOIEi6aRjVOwacbRq1Zin71YFBulpo/arWxONQw1h2y+UtLSZ BjAyNNT41ev1uYdzlw10wo5neozPBMpoFrds+Js8PmBYOJZKbqgKlMtz7Dgd5Ss9PGs5 NOeA== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@gmail.com header.b=BeGZ1APL; spf=pass (google.com: domain of ricardofabianodeandrade@gmail.com designates 2607:f8b0:400c:c05::22d as permitted sender) smtp.mailfrom=ricardofabianodeandrade@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=ND1pzuAWdfYFsIHO2lAX2KuI7PzYPWqG99CJgXWtM/c=; b=RR4o/Elw5kSA8vJnL62KfdYdQZfln6vfA8BfksOK8btaVqWx/ev+S+DelJp7NGjFjI 9ZDbYZVbavqADyolrqXwXRm+is/WCOj26ZnUYN6qA1VYoze8n4hyasseuiq/lW+iWwuj 72sujfKI1teaI5f9tpjKcF0Mc81Nq+db03r7NUXxwT6rH0vNX0cPwOB3DubACAyoaDT2 Cg7T2ePhjK6oqvRN3c5HXa5qFDc18x4uYPkrLTjw2iKgaGHOPZWSHjC9OM2PWzyjG0JU q56QEMXtG669NpXBmL1lBgOMHV+GvN09pNrWqNp/P2csmqiaJGfsabWXt3FYuohF9lme 5Bow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=ND1pzuAWdfYFsIHO2lAX2KuI7PzYPWqG99CJgXWtM/c=; b=Y4Ft/smSwUznWYcrauaNKtcOWRTKZJKqS2aVvs6xG/DH4hyHLfJHFcUhZ1UK+leBGY 8xEFGahJ+VRU+O5V2iBR5mPoRrmy5oNzgRwAGMu5Y1dz+GEOliMAvJUWTMHp+mreG7cm zoDrEX5mBBEKne5iDD0pLfsAWYLpl6B1Bhg1+FuIKkRs85LyX+TGpslO8IBal1GuAhpo BuMJMWUjLmv4khTkZpy8yMhVh+4SkybV/+AOKgaxdTXqpR+KUOMRMJHekYehig5Sap+d LXLQWiCYxEFNpftBJGyIpShZhzseJKzE58nLt/2Yg+BpAjMFWyblwOLgjCJD9FZnc6xK x2Pw== X-Gm-Message-State: AIVw112uX2r4HSdeuEe9w6HY9XD0NR4x9Qd3kMp44vOXjBaS9eEGFGyu mPGaoDCJCyzupYyJ X-Received: by 10.98.7.90 with SMTP id b87mr15206966pfd.43.1501697132249; Wed, 02 Aug 2017 11:05:32 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.36.202 with SMTP id f193ls3419769ita.17.canary-gmail; Wed, 02 Aug 2017 11:05:31 -0700 (PDT) X-Received: by 10.176.4.111 with SMTP id 102mr18541200uav.146.1501697130984; Wed, 02 Aug 2017 11:05:30 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1501697130; cv=none; d=google.com; s=arc-20160816; b=V8pzcoKFFBGmvwbleU0CPwp6+ezhTl4j2A67rXCqZkeJXDajL8VHaIqsrAavMbwMih k5pI+2VBEA4Vq5NEA5Uert7IXJHaPvtkyVHVyF2+2v62IOuZESTm5aUd3k68K588ZMrb DOZP0fNqgi3tKzH4PMNraDUB2tCKjkqReu9nQ9Adm8D7xfPNADCX6IOSXJzrZiVVaBHX t6c/MXvy7kH5w9Lmq1nc7+0LvbIlsyrVUOeCrN/JN7whF1+fJRcR3weDu3u2x/4QwTvj h79y+mlOR/ZqewHRMBzKhB5tgQn/FBS9DJ3uo4y0YHWDCgUXPYutDQupPtcLjXaY0NBC N9DQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :dkim-signature:arc-authentication-results; bh=7Lo2Nn5YyvTTLcVWPdiLb6e4+xeorrUqQBE4q+rQPkA=; b=Z5XSIXFZ2DfG8HOgA4jJQO9jH3x/s8VLnHzif4iyHT37Jn/7pLiBYyEipAOBhuYyNO 7o2wD7s/f3RkFd9v9p7UpD5I7mzmi0OvPNVAulDxvxvjGTrbnEiGMb5TSULwe4/azTOm pOwoQpoN8WxNhdG768j8I9eSiR1tVHjl2HsvZDbv+dHdZdyiPEJwmJDPhSVaa/FFszDD QStF/7Riyh7KXPPMRXHRnJLSRChCtgXYEEw3UHIadKf74vVwZISjfrST8crFx34zFAtv ZHX0mGB00sdm5Leu3gGwJAQz8KKHmFn7diknsZLbHpmy6YaSiMpZtT8Pk2vQqf7Lmn7z 81aA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.b=BeGZ1APL; spf=pass (google.com: domain of ricardofabianodeandrade@gmail.com designates 2607:f8b0:400c:c05::22d as permitted sender) smtp.mailfrom=ricardofabianodeandrade@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com Original-Received: from mail-vk0-x22d.google.com (mail-vk0-x22d.google.com. [2607:f8b0:400c:c05::22d]) by mx.google.com with ESMTPS id b28si3491960uaa.136.2017.08.02.11.05.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Aug 2017 11:05:30 -0700 (PDT) Received-SPF: pass (google.com: domain of ricardofabianodeandrade@gmail.com designates 2607:f8b0:400c:c05::22d as permitted sender) client-ip=2607:f8b0:400c:c05::22d; Original-Received: by mail-vk0-x22d.google.com with SMTP id x10so20961878vkd.0 for ; Wed, 02 Aug 2017 11:05:30 -0700 (PDT) X-Received: by 10.31.215.6 with SMTP id o6mr9751825vkg.179.1501697130553; Wed, 02 Aug 2017 11:05:30 -0700 (PDT) Original-Received: by 10.176.25.101 with HTTP; Wed, 2 Aug 2017 11:05:30 -0700 (PDT) In-Reply-To: X-Original-Sender: ricardofabianodeandrade@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.b=BeGZ1APL; spf=pass (google.com: domain of ricardofabianodeandrade@gmail.com designates 2607:f8b0:400c:c05::22d as permitted sender) smtp.mailfrom=ricardofabianodeandrade@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:33539 Archived-At: --001a114eccbc06e71a0555c91c88 Content-Type: text/plain; charset="UTF-8" Hum, a template... bikeshedding an alternate syntax: catch(auto& e) { ... do something } On Wed, Aug 2, 2017 at 8:38 AM, Matthew Woehlke wrote: > On 2017-08-02 08:47, Barry Revzin wrote: > >> And how to know which one invoked? You don't. If you wanted to know if > it > >> was exceptionA, you'd add a catch block for it. > > > > You'd almost want something like: > > > > catch (variant e) { > > visit([](auto& e){ f(e); }, e); > > } > > catch (exceptionA, exceptionB, exceptionC e) { > if constexpr (std::is_same_type_t) { > ...do something with exceptionA... > } > } > > IOW, implement such blocks sort of like templates; write the code once, > but the compiler internally converts it to separate catch-blocks with > the same bodies. > > -- > Matthew > > -- > 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/d58143f8-c128-3745- > b835-1e04a5760d0d%40gmail.com. > -- 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/CA%2BfGSbMB3%3DH4hetWu3GFPzUskLP_sh0Q%3DQ4oxsUsZ6ci-jrpxg%40mail.gmail.com. --001a114eccbc06e71a0555c91c88 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hum, a template... bikeshedding an alternate syntax:
<= br>
catch<exceptionA, exceptionB, exceptionC>(auto& e) = {
=C2=A0... do something
}

On Wed, Aug 2, 2017 at 8:38 AM, Ma= tthew Woehlke <mwoehlke.floss@gmail.com> wrote:
On 2017-08-02 08:47, Barry Revzin wrote:
>> And how to know which one invoked? You don't. If you wanted to= know if it
>> was exceptionA, you'd add a catch block for it.
>
> You'd almost want something like:
>
> catch (variant<exceptionA&, exceptionB&, exceptionC&>= ; e) {
>=C2=A0 =C2=A0 =C2=A0visit([](auto& e){ f(e); }, e);
> }

=C2=A0 catch (exceptionA, exceptionB, exceptionC e) {
=C2=A0 =C2=A0 if constexpr (std::is_same_type_t<decltype(e), except= ionA>) {
=C2=A0 =C2=A0 =C2=A0 ...do something with exceptionA...
=C2=A0 =C2=A0 }
=C2=A0 }

IOW, implement such blocks sort of like templates; write the code once,
but the compiler internally converts it to separate catch-blocks with
the same bodies.

--
Matthew

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-propo= sals+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/d58143f8-c128-3745-b835-= 1e04a5760d0d%40gmail.com.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/CA%2BfGSbMB= 3%3DH4hetWu3GFPzUskLP_sh0Q%3DQ4oxsUsZ6ci-jrpxg%40mail.gmail.com.
--001a114eccbc06e71a0555c91c88-- .