220 32384 article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: When C++ will support unconstrained generic functions ? Date: Wed, 10 May 2017 07:38:50 -0700 (PDT) Lines: 82 Approved: news@gmane.org Message-ID: References: <2b6b016d-3463-416b-afd5-d10bac62a334@isocpp.org> <3657aeea-1787-40ee-9320-9b6e6466f061@isocpp.org> <872d1f11-6ded-4398-9117-1c3871f364b4@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_5354_433557662.1494427131152" X-Trace: blaine.gmane.org 1494427132 29706 195.159.176.226 (10 May 2017 14:38:52 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 10 May 2017 14:38:52 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBB66LZTEAKGQEEPRHFNA@isocpp.org Wed May 10 16:38:48 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io0-f197.google.com ([209.85.223.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d8SlL-0007cC-D1 for gclcip-std-proposals@m.gmane.org; Wed, 10 May 2017 16:38:47 +0200 Original-Received: by mail-io0-f197.google.com with SMTP id j83sf2032666ioi.11 for ; Wed, 10 May 2017 07:38:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :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=uC+qtjii9ytKDXCfdh4ghzOb5ZK+Rvmnzb0c0OXRpdQ=; b=bjX3EJf+dCzAIcBJk/J8MXskdJLDDKATuQ7eSKMHtRPyzln4ge3/WeTS6c/16Wi5v2 huUXKKGs/i8ub1g+lGcqCmkpLKKfNDWYFzPOpxJ/EMXAsNYJNqZanVZzHPYzwwtwNzRX B0gUeHnups4WGZMTXz2+CCi59rzZxVOX5G6UPDIc3g1fG+lpD/ZBJvZ1DbSsGFbU6A/T jgjUO07XoU/kw5rPsDlDEJVlN0UDCQlD7X+sbHDYdOkOV5X2P4/Wn4NDVlFIN2iSflvY zvFA/v70UX8zuCVvE+dUVTnQuQzG7wI3m9AUccULCX0mb8l2DqcylI1U+BUAsxcvKjf6 DfjQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :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=uC+qtjii9ytKDXCfdh4ghzOb5ZK+Rvmnzb0c0OXRpdQ=; b=FJSGRIE5Iy1ULKrMX3rWdiWC6RIRjgWYOTFxSO3VR3XjwWtDhFlKmbptRgrxrae/vg Q4o2l+ryjjsDTVd/EXV6fAsGoYGDfF5JmNmz5emqfX8O9Lq/o1UU9EftW3PtjIpxZWjd yHSk2qrWPaZXcUH5UVmb5rx2LzYjg8roObt/xcvSxA6Kn6fYrvsrMcRv9N4tFbwkKibl Q0cNQIucbgWLXLgxYhkq/sS0Xp3TYxfBUmkrz4vZxFuAQYF8jrrwoKHijgAB8eB50y5Y LtqyDpNh+YOgtYtzOD47dljUYSbK4gOJYn92OvXYqvKgFYnFXD3tkHe8I1ZH7Cxs30CY Tc9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version: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=uC+qtjii9ytKDXCfdh4ghzOb5ZK+Rvmnzb0c0OXRpdQ=; b=dtw24KRlq7GR/haCxplMXWhFc61GJ8cK2/uXc6DuhSU3ob0MX3uOTgCzUhsr7J0VQ9 QokQRjAoGlQxJiZrlwHT1SVkUhlkqlAMIFByYM4sVSISMX/tmuHWTCIVwkiHdrD5LvVf Dr6VDcoJOYqTND5Ycf667RnX5+WwR+vnW82cmT1emEqnQeYZfvpT3CUcCz3dmLMi7qng R0ApQHpXy2gMN1NuHZbgmED0XqCnuhyApcGJ/vMxkFT5dhw1r2inZLX7o7Yo8baDoICu TNLj2k3aIwj9Ef0e5Kqpm+evJR4qnWHd9Yht1yn1Eqma5VG6kwO2BlVkiMXQmZcwQPN4 VzaA== X-Gm-Message-State: AODbwcDHUIgx8SZrVPdO53H4q5hXJgHlAN+u45pBYWN5U33AQUiXyepK ouMifqvFyxz+rg== X-Received: by 10.36.50.136 with SMTP id j130mr2473525ita.36.1494427132582; Wed, 10 May 2017 07:38:52 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.56.90 with SMTP id r26ls2976796otd.0.gmail; Wed, 10 May 2017 07:38:51 -0700 (PDT) X-Received: by 10.157.35.104 with SMTP id k37mr135736otd.14.1494427131676; Wed, 10 May 2017 07:38:51 -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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:32384 Archived-At: ------=_Part_5354_433557662.1494427131152 Content-Type: multipart/alternative; boundary="----=_Part_5355_1182279934.1494427131152" ------=_Part_5355_1182279934.1494427131152 Content-Type: text/plain; charset="UTF-8" On Wednesday, May 10, 2017 at 12:15:25 AM UTC-4, Anthony Hall wrote: > > It is my impression that the Modules TS will obviate some of the need to > write function templates only inside of header files -- something akin to > what had been intended with export templates, but that the related > technical issues are actually soluble. Is that impression correct? Is > that too simplistic and naive a view of it? > > If that impression *is* correct, would the concerns about terse function > template syntax be resolved, specifically, it not being immediately clear > from the form of the declaration itself whether the function is a template > or not, and should therefore be implemented in a header rather than a cpp > file? > You assume this is the only difference between a template function and a non-template function. You can't get function pointers to template functions (unless you explicitly provide all template parameters, which means you have to know what they are). If we had so-called "lifting lambdas" (the ability to easily create a lambda that calls a function by name), this wouldn't be much of an issue. But since we don't, it remains an issue. -- 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/b6a2673a-ebfa-4b8d-88fd-2f2a48f06526%40isocpp.org. ------=_Part_5355_1182279934.1494427131152 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Wednesday, May 10, 2017 at 12:15:25 AM UTC-4, A= nthony Hall wrote:
It is my impression that the Modules TS will obviate some of the need = to write function templates only inside of header files -- something akin t= o what had been intended with export templates, but that the related techni= cal issues are actually soluble. =C2=A0Is that impression correct? =C2=A0Is= that too simplistic and naive a view of it?

If that impression i= s=C2=A0correct, would the concerns about terse function template syntax= be resolved, specifically, it not being immediately clear from the form of= the declaration itself whether the function is a template or not, and shou= ld therefore be implemented in a header rather than a cpp file?

You assume this is the only difference between a template f= unction and a non-template function. You can't get function pointers to= template functions (unless you explicitly provide all template parameters,= which means you have to know what they are). If we had so-called "lif= ting lambdas" (the ability to easily create a lambda that calls a func= tion by name), this wouldn't be much of an issue. But since we don'= t, it remains an issue.

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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/b6a2673a-ebfa-4b8d-88fd-2f2a48f06526= %40isocpp.org.
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