220 36506 <7A4EE214-FE5B-4EC2-BE9E-23522F55EE5B@gmail.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Jonathan Coe Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Currying or Partial Application Date: Sat, 6 Jan 2018 15:13:11 +0000 Lines: 292 Approved: news@gmane.org Message-ID: <7A4EE214-FE5B-4EC2-BE9E-23522F55EE5B@gmail.com> References: <835cc86a-2e6c-4e17-aec7-4f16cf8b085f@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 (1.0) Content-Type: multipart/alternative; boundary=Apple-Mail-426FBF5A-A15F-43F1-A56B-B36C01A4AD04 Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1515251481 31044 195.159.176.226 (6 Jan 2018 15:11:21 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 6 Jan 2018 15:11:21 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC2JVFPBRAHBBC6PYPJAKGQEZ6OHBSI@isocpp.org Sat Jan 06 16:11:17 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wm0-f70.google.com ([74.125.82.70]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eXq7s-0007PA-Ou for gclcip-std-proposals@m.gmane.org; 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[209.85.220.41]) by mx.google.com with SMTPS id w102sor3538124wrb.45.2018.01.06.07.13.14 for (Google Transport Security); Sat, 06 Jan 2018 07:13:14 -0800 (PST) Received-SPF: pass (google.com: domain of jonathanbcoe@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 10.223.190.12 with SMTP id n12mr5276748wrh.102.1515251594119; Sat, 06 Jan 2018 07:13:14 -0800 (PST) Original-Received: from [10.85.118.86] ([149.254.248.86]) by smtp.gmail.com with ESMTPSA id 52sm9027670wrz.80.2018.01.06.07.13.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 06 Jan 2018 07:13:12 -0800 (PST) In-Reply-To: <835cc86a-2e6c-4e17-aec7-4f16cf8b085f@isocpp.org> X-Mailer: iPhone Mail (15C153) X-Original-Sender: jonathanbcoe@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=QrFnmyt6; spf=pass (google.com: domain of jonathanbcoe@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=jonathanbcoe@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-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:36506 Archived-At: --Apple-Mail-426FBF5A-A15F-43F1-A56B-B36C01A4AD04 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > On 6 Jan 2018, at 14:12, Sarfaraz Nawaz wrote: >=20 >=20 > As C++ is becoming more functional with its each release, I think we shou= ld also think in the direction of function partial application. >=20 > Here is one syntax (inspired from Scala): >=20 >=20 > int f(int a)(int b)(int c) // #1 > { > return a + b + c; > } >=20 >=20 > f(10, 20, 30); // normal. full application >=20 > f(10, 20)(30); // partial application >=20 > f(10)(20, 30); // partial application >=20 > f(10)(20)(30); // partial application >=20 >=20 >=20 > Now what if we have an overload function like: >=20 >=20 > int f(int a)(std::string b)(int c) // #2 > { > //... > } >=20 >=20 >=20 > then `f(10)` is ambiguous. In that case, we could disambiguate as: >=20 >=20 > auto f1 =3D f(10)(int); //Or auto f1 =3D f(10) :: (int) ... stealing fro= m Haskell? >=20 > f1(20, 30); // calls #1 >=20 > auto f2 =3D f(10)(std::string);=20 >=20 > f2("Might work")(20); //calls #2 >=20 >=20 >=20 >=20 > Thoughts? >=20 Do you have an example of how this would allow one to re-write code in a mo= re maintainable way? I=E2=80=99m not familiar with Scala or the advantages = that partial application can bring. Thanks Jon > --=20 > 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/isoc= pp.org/d/msgid/std-proposals/835cc86a-2e6c-4e17-aec7-4f16cf8b085f%40isocpp.= org. --=20 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 e= mail 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/7A4EE214-FE5B-4EC2-BE9E-23522F55EE5B%40gmail.com= .. --Apple-Mail-426FBF5A-A15F-43F1-A56B-B36C01A4AD04 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On 6= Jan 2018, at 14:12, Sarfaraz Nawaz <nawazzz@gmail.com> wrote:

<= div>

As C++ is becoming more functional= with its each release, I think we should also think in the direction of fu= nction partial application.

Here is one syntax (in= spired from Scala):


int f(int a)(int b)(int c)  <= /span>// #1
{
   return a + b + c;}=


f(10, 20, = 30); // normal. full applicati= on

= f(<= span style=3D"color: #066;" class=3D"styled-by-prettify">10, 20)(30);= // partia= l application

f(10)(20, 30); // partial application

f(10)(20)(30= ); = // partial application



Now wha= t if we have an overload function like:

=

int f(int a)(std::string b)(int c)  // #2
= {
  <= span style=3D"color: #800;" class=3D"styled-by-prettify">//...
}



then `f(10)` is ambiguo= us. In that case, we could disambiguate as:


auto f1 =3D f(10)(int); //Or  auto f1 =3D f(10) :: (int) ... stealing = from Haskell?

f1(20, 30); // calls #1

auto f2 =3D f(10)(std<= /span>::string);

f2("Might work")(20); //calls #2




Thoughts?


Do you have an example of how this would allow one to re-write cod= e in a more maintainable way? I=E2=80=99m not familiar with Scala or the ad= vantages that partial application can bring.

Thank= s

Jon

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