220 6295 <16095487.EtSydgjv4x@tjmaciei-mobl2> article Path: news.gmane.org!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: type signatures or constraints for callable entity type parameters Date: Sun, 08 Sep 2013 11:23:56 -0700 Lines: 50 Approved: news@gmane.org Message-ID: <16095487.EtSydgjv4x@tjmaciei-mobl2> References: <1e742e51-3e95-4a3b-bcb8-2052751e77a7@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1789990.jYEky4ESJk"; micalg="pgp-sha1"; protocol="application/pgp-signature" X-Trace: ger.gmane.org 1378664666 21371 80.91.229.3 (8 Sep 2013 18:24:26 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 8 Sep 2013 18:24:26 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBWUBWOIQKGQERWQTI6I@isocpp.org Sun Sep 08 20:24:27 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ea0-f198.google.com ([209.85.215.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VIjet-0005Kf-Kk for gclcip-std-proposals@m.gmane.org; Sun, 08 Sep 2013 20:24:27 +0200 Original-Received: by mail-ea0-f198.google.com with SMTP id z15sf4533705ead.9 for ; Sun, 08 Sep 2013 11:24:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=from:to:subject:date:message-id:user-agent:in-reply-to:references :mime-version:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=/XcZskOPD+OhFrEmqJenziTt5pQPjesHIDIOhSu/xOY=; b=juyB6cQqFFXmCrgM3rUhXdvj02VVEhkkKYhEMQ3FKilYMnsBHnA/VRwGXLvov2Fif4 ipbxx1Am77Hc5l4FTm+gIW9VYtEKD1+Ns8L+brzTxJ8pEI28r2W344igZUDtkkLhfkpE 7dxjvpd6vEX3TDCDA9NqX55VDz121hFwY66zKG0izWrZQpfNM5wuSkac4mKiINfOIQVt Aazmd07BqPY69Y6e4x9MFQgZzC4E2WHefyb1QmB7RSj91JJYMEji6iTcrrtRpgPnX2Is CK9Ug5zAPA2BL8SKEfCFE4kXWykHmVqFERXyBimscz94vUw5rebq+O9Sv4qp01q+6SAP swaw== X-Received: by 10.180.208.35 with SMTP id mb3mr2210176wic.2.1378664667388; Sun, 08 Sep 2013 11:24:27 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.77.135 with SMTP id s7ls533756wiw.28.canary; Sun, 08 Sep 2013 11:24:26 -0700 (PDT) X-Received: by 10.204.224.142 with SMTP id io14mr330787bkb.27.1378664666102; Sun, 08 Sep 2013 11:24:26 -0700 (PDT) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by mx.google.com with ESMTP id t8si888831bkp.38.1969.12.31.16.00.00; Sun, 08 Sep 2013 11:24:25 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) client-ip=2a01:4f8:d13:f81:21c:14ff:fe01:12a3; Original-Received: from tjmaciei-mobl2.localnet (unknown [IPv6:2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by gondolin.macieira.info (Postfix) with ESMTPSA id 2C30212C018 for ; Sun, 8 Sep 2013 11:24:25 -0700 (PDT) User-Agent: KMail/4.12 pre (Linux/3.9.10-100+i915fix.fc17.x86_64; KDE/4.11.60; x86_64; git-8054221; 2013-08-01) In-Reply-To: <1e742e51-3e95-4a3b-bcb8-2052751e77a7@isocpp.org> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) smtp.mail=thiago@macieira.org 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:6295 Archived-At: --nextPart1789990.jYEky4ESJk Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On domingo, 8 de setembro de 2013 04:13:11, snk_kid wrote: > type signatures or constraints for callable entity type parameters > > Something I'd like to see fixed in the near future is being able to specify > in the type system (and also get documentation-for-free) is what the > parameters & return type must be of a callable entity template parameter. > What I mean by this is currently when writing a higher-order function in > C++ such as: > > template < typename Function > > void foo(Function bar); > > Without looking at the definition of 'foo' or without documentation it is > impossible to tell what kind of parameters/return type is expected of 'fn'. > > Maybe a template constraint such as this would be possible: > > template< typename Fn > requires Function() > void foo(Fn bar); That's concepts-lite. Can you write your proposal in terms of what needs to be added to the language on top of concepts-lite? -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center PGP/GPG: 0x6EF45358; fingerprint: E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 --nextPart1789990.jYEky4ESJk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iD8DBQBSLMDXM/XwBW70U1gRAnpZAKCcOb9uBxt5NnXYg11S0IQDm8mf8ACgndIc gBcNyL8htq4rKdXMPQI32c0= =yNpL -----END PGP SIGNATURE----- --nextPart1789990.jYEky4ESJk-- .