220 20681 article Path: news.gmane.org!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Null -conditional and -coalescing operators Date: Tue, 22 Sep 2015 19:53:07 -0700 (PDT) Lines: 105 Approved: news@gmane.org Message-ID: References: <4c3e2ee7-2159-4e93-a439-7d5c94c38c9c@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_7076_99725498.1442976787356" X-Trace: ger.gmane.org 1442976793 20876 80.91.229.3 (23 Sep 2015 02:53:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 23 Sep 2015 02:53:13 +0000 (UTC) Cc: joewoodbury@gmail.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBFFIRCYAKGQEFWHA6RI@isocpp.org Wed Sep 23 04:53:13 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pd0-f198.google.com ([209.85.192.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZeaBC-0002C9-IO for gclcip-std-proposals@m.gmane.org; Wed, 23 Sep 2015 04:53:10 +0200 Original-Received: by pdbpr5 with SMTP id pr5sf47658522pdb.2 for ; Tue, 22 Sep 2015 19:53:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-type:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=By3+vDxW0DCfD6gp2h5xGT/ZPx0QDxUsxr/rDsEfK6Q=; b=yePAO3oJU9ACucywGRsHGbBIlOhbjE8glD6sb8SizC4cPla+Ze0bm9JHCCWAWKf68t /UzmwAe0pkgDIFYfTrHwNpDHqCDAJwrsi2gcmqXtI2omDybq4dPozMTc//zuFVaVEE61 +xioUkEGKKdiUN6Cp0VIO0UEl+ECzfoHpAeqglY2JnmNWueMRu0l3pjtk+Yfm2gEDk/e Nro1d9+3sKnlG7OJYF5Ra6SNID1xFnc1VTqK6thg0QH+ZlacgSWcE79xWMls7VZJ3zpv 4ovb5A7Bp22Y+NoH9f01zXL4osJ/hT2dGNb4mNmQ8hR4Z/uxcIQxzsBJZ28Tknh1LbnG 1A5w== 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:cc:message-id:in-reply-to :references:subject:mime-version:content-type:x-original-sender :reply-to:precedence:mailing-list:list-id:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=By3+vDxW0DCfD6gp2h5xGT/ZPx0QDxUsxr/rDsEfK6Q=; b=VsuwLyPPPClMi/DhsvwpvLgVIiLfMEBqCDZtcFCPJsy8XZ9LfykyUXIjiCVW90XDlf vJtvHHvHD8Ao8OcM1ksBwcx1XssoF9mqEBKqyS8TVhzY+DsxoB6f9AFUT+DtZjPXHZgM fWW5PLWeJrVeFuZ8JSv1kzdGdfNMN7TIfO9Cb+JtqfSu1wcpIkhoCE5MvzhRVLsNeNWw K08WrTJ8Cltg3DuxpRuEna6BI0Ty9iY7Qaq/zXh21L2tpOkIGzk+UAnK+BtIjkl4oMy+ CRcP8SuwYuBxkktB7Tm+MvMVp4No6PIijfQXPPTFWzHgSSxF71hPfuDcKfQJcnAb5v9Q OZYg== X-Gm-Message-State: ALoCoQmYi7qqBEH4kP+MgPfNuHDmrBvQ3lUxm8gBxdETvVnQOJL+dhwKLk3HFbvktwTXl9Swbp7j X-Received: by 10.66.197.136 with SMTP id iu8mr24981542pac.47.1442976789259; Tue, 22 Sep 2015 19:53:09 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.163.11 with SMTP id m11ls339266ioe.59.gmail; Tue, 22 Sep 2015 19:53:08 -0700 (PDT) X-Received: by 10.50.66.205 with SMTP id h13mr237655igt.10.1442976788412; Tue, 22 Sep 2015 19:53:08 -0700 (PDT) In-Reply-To: X-Original-Sender: jmckesson@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:20681 Archived-At: ------=_Part_7076_99725498.1442976787356 Content-Type: multipart/alternative; boundary="----=_Part_7077_1075964204.1442976787356" ------=_Part_7077_1075964204.1442976787356 Content-Type: text/plain; charset=UTF-8 On Tuesday, September 22, 2015 at 8:34:20 PM UTC-4, joewo...@gmail.com wrote: > > Here in interesting example I just encountered: > > strLen is passed into a function along with pStr. After nullptr checks, > the following is done: > > size_t tmpStrLen = wcslen(pStr); > if (strLen > tmpStrLen) > strLen = tmpStrLen; > > Using the ?: operator, you could do: > > strLen = wcslen(pStr) < strLen ?: strLen; > > Again, a trivial example, but one in actual code. > And this code would have made it much more clear what you were doing: strLen = std::min(wcslen(pStr), strLen); Also, I'm not sure how your suggestion is equivalent to the original. I see you have an expression that evaluates to bool. And I see you have an expression which will be evaluated if the boolean expression is true. I don't see what the value of that expression will be if the boolean expression is false. So I'm not clear on exactly what your code means. -- --- 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. 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On Tuesday, September 22, 2015 at 8:34:20 PM UTC-4= , joewo...@gmail.com wrote:
Here in interesting example I just encountered:

strLen= is passed into a function along with pStr. After nullptr checks, the follo= wing is done:

=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2= =A0 size_t tmpStrLen =3D wcslen(pStr);
=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0= =C2=A0 =C2=A0=C2=A0=C2=A0 if (strLen > tmpStrLen)
=C2=A0=C2=A0=C2=A0 = =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 strLen =3D tmpStrL= en;

Using the ?: operator, you could do:

=C2=A0=C2=A0=C2=A0 = =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 strLen =3D wcslen(pStr) < strLen ?= : strLen;

Again, a trivial example, but one in actual code.

And this code would have made it much mo= re clear what you were doing:

strLen =3D std::min(wcslen= (pStr), strLen);

Also, I'm not= sure how your suggestion is equivalent to the original. I see you have an = expression that evaluates to bool. And I see you have an expression which w= ill be evaluated if the boolean expression is true.

I don't see = what the value of that expression will be if the boolean expression is fals= e. So I'm not clear on exactly what your code means.

--

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