220 34592 article Path: news.gmane.org!.POSTED!not-for-mail From: Todd Fleming Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: operator try (was Re: Proposal: Monadic operations for std::optional) Date: Wed, 4 Oct 2017 06:11:48 -0700 (PDT) Lines: 146 Approved: news@gmane.org Message-ID: References: <49346690-6184-690b-bba5-0c2c0db4b8f0@wanadoo.fr> <7afe3e3e-7f0c-406b-a44e-ff38834c8d39@isocpp.org> <71754ee5-bdbd-4826-82f9-a0ccb4950335@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_8174_1486704175.1507122708969" X-Trace: blaine.gmane.org 1507122714 29431 195.159.176.226 (4 Oct 2017 13:11:54 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 4 Oct 2017 13:11:54 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDN5JUVZSIFBBFN42PHAKGQEH5UCJYI@isocpp.org Wed Oct 04 15:11:46 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io0-f198.google.com ([209.85.223.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dzjSi-0006en-5E for gclcip-std-proposals@m.gmane.org; Wed, 04 Oct 2017 15:11:44 +0200 Original-Received: by mail-io0-f198.google.com with SMTP id j123sf701793ioe.15 for ; Wed, 04 Oct 2017 06:11:51 -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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=DFbCxjLhhNHR7dIJrW+dL6Cyd2VWCGNTfsQcf6k0B78=; b=ScimO35iqfiKvg6Ix1RBrNPiJLlShVZX2wohY1bE42fHpMCZ3xDEea7DHf5A3eihtK BN1j3xgHLeFUh9LorQvE+opr2Ax5dpJ8/GJcOsrhAFuo3dIV/hWfK7nVs4Ro+s9kTiDN oMYTnhKFyRGQdGg73OqkLnQ5b7PDuxwn/bPK/2PyXd44sR1EnAI+xmPV1svoRv2GfLwW yNy75cPyqgURDZ1r85rZQaoZ7A1lvSfW+bFSsFi77yqw3Hk6nGM06BQkFccgZ21gW9s4 Gb8Rn33jCXHHIiNPtkoJq4HBYIW6BmQJpO2TqgTSwzqZCl4PsvCIo6kfKuGWW2ZNiM+4 TE+g== 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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=DFbCxjLhhNHR7dIJrW+dL6Cyd2VWCGNTfsQcf6k0B78=; b=e92GDiBCaLbzNGQCc+F8HxQA1ztR4RVOzYLUSrMlF6dlLn2eeWYZeH5ekruqbh8i6J WOqcCgOigzfZx/ro6x8zvqD3TIonLlve/eQhHC6JAd00IyPPfKe9ZUqel3blndgO/59M oZpfSIPR5HvnRmRL/xyqHQiPXBijGXoKLes7HKkbGKwNrHdxUGoDhojci7McXPrWF1ey VPF/YCxhjrhHObBmVJLgwQhLRn/w4hWIBQfiJzP9g0DgKaOKydVf2n53+Jy94V5M+ct9 76ko++ol7PHedgCOC8aFZ075PRDzGUqqStGKN4RXM7lP7NLLuWqjuk1AVCd33AWcOsu3 q/jA== 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=DFbCxjLhhNHR7dIJrW+dL6Cyd2VWCGNTfsQcf6k0B78=; b=lngEH95bVGzLRm3lafxbqZ4jMbLIalg4BAaLWC8w+zKcx/iAu9BbG6cz6ipetPxgLa aKOqZPQLn8NiOEAlSXkiR66DhrjQB+/6CG5Fp1Hvmp8DOrDTcRXKyNEwSz8Ys0qJoSeg +UI1mmoTsYCQma6WciVsFf2SaOMiDWOeinBfn54VLzhRr4yt8orqvX8eogBZcfCpsKY8 VvL4pp5s4LfvLDvOCmmKw6mI96L6um2RmQaRp5PcZGzoDyjesdnvLxRlw/ANusBVcqJQ w+yS5JXho2jiNNg+yZWusf1wExuje/Cxkp86Fw5X4GsADqTc7u00yMNWaFFZ/C0iTXJw nuCw== X-Gm-Message-State: AHPjjUicLAzc3zS6DJe0UE/A0XoKM8aEhXfgIHp7wW2PKjA9x6zkcIkN GhoHbhsmzVO4lTFv2VZP5DDMRQ== X-Google-Smtp-Source: AOwi7QBJD2VW7CaCJNp8YXrcjOIZV8NJzJMAx4PRkHXRpljgr4Ej19sxW/vYm+W0hSmL1jpHUU5CwQ== X-Received: by 10.159.61.17 with SMTP id l17mr4661908uai.43.1507122711262; Wed, 04 Oct 2017 06:11:51 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.31.134.13 with SMTP id i13ls5017514vkd.7.gmail; Wed, 04 Oct 2017 06:11:49 -0700 (PDT) X-Received: by 10.31.167.75 with SMTP id q72mr913863vke.22.1507122709518; Wed, 04 Oct 2017 06:11:49 -0700 (PDT) In-Reply-To: <71754ee5-bdbd-4826-82f9-a0ccb4950335@isocpp.org> X-Original-Sender: tbfleming@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:34592 Archived-At: ------=_Part_8174_1486704175.1507122708969 Content-Type: multipart/alternative; boundary="----=_Part_8175_1223612708.1507122708970" ------=_Part_8175_1223612708.1507122708970 Content-Type: text/plain; charset="UTF-8" Maybe a library function could do this: return try_(a, f, g, h); Todd On Wednesday, October 4, 2017 at 12:24:33 AM UTC-4, Ray Hamel wrote: > > To clarify a bit, I'm suggesting infix `try` take an expression on the > left and a > callable on the right, so > > return a try f try g try h; > > would be the semantic equivalent of the second snippet (with prefix `try > `). > > Ray > > On Wednesday, October 4, 2017 at 12:04:35 AM UTC-4, Ray Hamel wrote: >> >> I think it would make more sense and be more functional / useful for `try` >> to >> be an infix than a prefix operator, so you could do >> >> return f(a) try g try h; >> >> instead of >> >> auto b = try f(a); >> auto c = try g(b); >> return try h(c); >> >> Infix `try` would also be harder to confuse with its present use in >> `try`-`catch` blocks. (And, for the same reason, simpler to parse as >> well). >> >> Ray >> >>> >>> -- 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/f936c4ce-7661-4785-a017-5d427c25776b%40isocpp.org. ------=_Part_8175_1223612708.1507122708970 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Maybe a library function could do this:

return= =C2=A0try_(a,=C2=A0f,=C2=A0g,=C2=A0h);=

Todd

On Wednesday, October 4, 201= 7 at 12:24:33 AM UTC-4, Ray Hamel wrote:
To clarify a bit, I'm suggesting infix `try` take an expressio= n on the left and a
callable on the right, so

return a try f try g try h;

would be the semantic equivalent of the second snippet (w= ith prefix `try`).=

Ray

On Wednesday, October 4, 2017 at= 12:04:35 AM UTC-4, Ray Hamel wrote:
I think it would make more sense and be more functio= nal / useful for `try` to
be an infix than a prefix operator, so you could do

= return f(a) try g try h;
=

instead of

auto b =3D try f(a);=
auto c =3D= try g<= /span>(b);
= return = try h(c);

Infix `try= ` would also be harder to confuse with its present use in
= `try`-`catch` blocks. (And, for the same reaso= n, simpler to parse as well).

Ray

=20

--
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/f936c4ce-7661-4785-a017-5d427c25776b= %40isocpp.org.
------=_Part_8175_1223612708.1507122708970-- ------=_Part_8174_1486704175.1507122708969-- .