220 12064 article Path: news.gmane.org!not-for-mail From: jeaye Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Variadic catch Date: Fri, 25 Jul 2014 05:58:31 -0700 (PDT) Lines: 160 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_2076_1225168522.1406293111232" X-Trace: ger.gmane.org 1406293123 9123 80.91.229.3 (25 Jul 2014 12:58:43 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 25 Jul 2014 12:58:43 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDMKNZOF2QLBB6FIZGPAKGQETQKJZUI@isocpp.org Fri Jul 25 14:58:36 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f72.google.com ([209.85.219.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XAf50-0002WJ-8o for gclcip-std-proposals@m.gmane.org; Fri, 25 Jul 2014 14:58:34 +0200 Original-Received: by mail-oa0-f72.google.com with SMTP id m1sf25544406oag.7 for ; Fri, 25 Jul 2014 05:58:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:subject:mime-version:x-original-sender :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:list-subscribe:list-unsubscribe:content-type; bh=qxEYd7Qn7rYeru60TrTvOq5tOMUUF8zHLR+uj9BQtd8=; b=EIpyCn/wiS4vk98GyO8wQ61usAfSeA2oqfwwqRC4f9N7Fn6ntsfxXm8qZSaVDzlInr uwIG3kZfcKfHJ41v3cyPDwBKa/qXrYXmBAtunofy+r9JcZTqYFDLtwECKDOyHJOmgaMv 2KuWjCZeHhy88PKhAoD+M2JF7x0gqBsH28xpYgXFSeM7zdyoKjp0uxMzTKf1/Ztb35dI /AYaIsMHXzg+K+jaGBVKnjNvkT5g58VYqlkXzlXQbZvzw18Q2g9ADKgPOZiEfZ9dlMEe czTnx0uQxISqt7ZpLNOhXZPM0fZgMxNvCLMFXgOJwKc/jjYWKGKa0NFARQ29wTlBgPZs 6Y9w== 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:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=qxEYd7Qn7rYeru60TrTvOq5tOMUUF8zHLR+uj9BQtd8=; b=JT4NK017nBtVAicaAiyRYdfu9ih+npXboWFjLXgS7UPcI07C0OdFo8hkgfIBs8ciXz PATxqYriSbOxtU60tR1T7aK5ZRuJxsgwGrzhwmN33SVnVqrrbnF5+5q+5tcLD7rb+Sfu By70i6QLV9nOHNNCRGPOF3lUbunRhfXOpQ+9gD9z6zgR6hPGzljp98dq6Cb5LeN02K3L l2vpPWKaK/L0zu6+6nKQON7lsvav9e6T97fyBanSrfPO7elqGkEwsC9+nrqwwp21qg7L jMLVM6JJetO+xmJ0h2K7zJ8YuuQB7/g3qu0fyNvCGJAxuz55hj661i3m6SD37o1dn3yB OZew== X-Gm-Message-State: ALoCoQlJ5D/6iWkh8W8HhfeL0av2iFaegrPmp9GnATyqpL4COzAxYB0wFrHTjACcgbyZ4FW53vKk X-Received: by 10.42.123.148 with SMTP id s20mr7210433icr.8.1406293113301; Fri, 25 Jul 2014 05:58:33 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.253.133 with SMTP id aa5ls421861igd.17.canary; Fri, 25 Jul 2014 05:58:32 -0700 (PDT) X-Received: by 10.50.20.168 with SMTP id o8mr101848ige.12.1406293112556; Fri, 25 Jul 2014 05:58:32 -0700 (PDT) X-Original-Sender: LorgonJortle@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:12064 Archived-At: ------=_Part_2076_1225168522.1406293111232 Content-Type: text/plain; charset=UTF-8 While implementing a unit test framework in modern C++, I found that I wanted an interface for expecting exceptions like: expect_exception([&]{ do_work(); }); This lead me to wonder, "what if it were variadic?" expect_exception([&]{ do_other_work (); }); Unfortunately, the implementation of this is not possible in C++11 or C++1y, since param pack expansion in a catch is impossible. So, I am interested in the group's thoughts on an extended syntax for param pack expansion, similar to sizeof...(Ts), but for catch. It would work as follows, continuing with my previous examples: template void expect_exception(std::function const &f) try { f(); } catch...(Ts const &ex) { std::cerr << ex.what() << std::endl; } Thanks for your time. -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. ------=_Part_2076_1225168522.1406293111232 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
While implementing a unit test framework in modern C++, I = found that I wanted an interface for expecting exceptions like:

expect_exception= <std::runtime_error>([&]{ do_work(); });

This lead me to = wonder, "what if it were variadic?"

expect_exception<std::runtime_error, std::out_= of_range&g= t;([&]{ do_other_work(); <= /span>});<= span style=3D"color: #000;" class=3D"styled-by-prettify">
<= /code>

Unfortunately, the implementation of this is not possible i= n C++11 or C++1y, since param pack expansion in a catch is impossible. So, = I am interested in the group's thoughts on an extended syntax for param pac= k expansion, similar to sizeof...(Ts), but for catch. It would work as foll= ows, continuing with my previous examples:

template <typename... Ts><= /span>
= void expect_exception(std::function<void ()> c= onst &f)
try
{ f(); }
catch...(Ts const &= ex)=
{ std::cerr << ex.what() <<= std::endl; }

Thanks for your time.
 = ;

--

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
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