From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-2.8 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, FORGED_GMAIL_RCVD,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_PASS shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id 75F2A20248 for ; Wed, 17 Apr 2019 05:06:00 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 0D255120938; Wed, 17 Apr 2019 14:05:55 +0900 (JST) Received: from o1678948x4.outbound-mail.sendgrid.net (o1678948x4.outbound-mail.sendgrid.net [167.89.48.4]) by neon.ruby-lang.org (Postfix) with ESMTPS id 3D54A1208E4 for ; Wed, 17 Apr 2019 14:05:52 +0900 (JST) Received: by filter0021p3iad2.sendgrid.net with SMTP id filter0021p3iad2-15359-5CB6B42F-13 2019-04-17 05:05:51.343220735 +0000 UTC m=+126193.892895586 Received: from herokuapp.com (unknown [100.26.191.192]) by ismtpd0050p1iad1.sendgrid.net (SG) with ESMTP id fl9S1DneTVOoo3Dfjfy24Q for ; Wed, 17 Apr 2019 05:05:51.270 +0000 (UTC) Date: Wed, 17 Apr 2019 05:05:51 +0000 (UTC) From: eregontp@gmail.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 67795 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 14183 X-Redmine-Issue-Author: mame X-Redmine-Sender: Eregon X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?KippOI8ZHtTweq7XfQzW93937kJ4QNWwSBuHnaMEcr3P8zkbAqPSvfO1zpM2dN?= =?us-ascii?Q?D6dqvemE8qzaN43VyfZFJOze3v2R4nT2xd7PHbr?= =?us-ascii?Q?igLaB2n2ZNYSkjo=2FQ3U0DCGFUgago4tPmJP1XWh?= =?us-ascii?Q?=2F6QRDSkppaYlyLShLBJIKkjLboindIdjhh2moHf?= =?us-ascii?Q?SZUigjCgdHyBD0VhVnOEwHeKvAjfSKGsvJA=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 92312 Subject: [ruby-core:92312] [Ruby trunk Feature#14183] "Real" keyword argument X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #14183 has been updated by Eregon (Benoit Daloze). With Jeremy's proposal, I think there is no need to support non-Symbol keywords. I think in the case of ActiveRecord or Sequel's #where, the method doesn't need to accept keywords, it can just accept a Hash. This Hash might contain numbers or strings as keys, and as such doesn't feel like "keywords arguments" to me. For instance, method definitions do not have a way to specify non-Symbol keywords. Re current behavior of splitting a Hash passed as keyword argument, mixing Symbols and non-Symbols keys, I would just raise an ArgumentError or TypeError if the Hash contains a non-Symbol key. It's somewhat similar to the "missing keyword" ArgumentError. ---------------------------------------- Feature #14183: "Real" keyword argument https://bugs.ruby-lang.org/issues/14183#change-77655 * Author: mame (Yusuke Endoh) * Status: Open * Priority: Normal * Assignee: * Target version: Next Major ---------------------------------------- In RubyWorld Conference 2017 and RubyConf 2017, Matz officially said that Ruby 3.0 will have "real" keyword arguments. AFAIK there is no ticket about it, so I'm creating this (based on my understanding). In Ruby 2, the keyword argument is a normal argument that is a Hash object (whose keys are all symbols) and is passed as the last argument. This design is chosen because of compatibility, but it is fairly complex, and has been a source of many corner cases where the behavior is not intuitive. (Some related tickets: #8040, #8316, #9898, #10856, #11236, #11967, #12104, #12717, #12821, #13336, #13647, #14130) In Ruby 3, a keyword argument will be completely separated from normal arguments. (Like a block parameter that is also completely separated from normal arguments.) This change will break compatibility; if you want to pass or accept keyword argument, you always need to use bare `sym: val` or double-splat `**` syntax: ``` # The following calls pass keyword arguments foo(..., key: val) foo(..., **hsh) foo(..., key: val, **hsh) # The following calls pass **normal** arguments foo(..., {key: val}) foo(..., hsh) foo(..., {key: val, **hsh}) # The following method definitions accept keyword argument def foo(..., key: val) end def foo(..., **hsh) end # The following method definitions accept **normal** argument def foo(..., hsh) end ``` In other words, the following programs WILL NOT work: ``` # This will cause an ArgumentError because the method foo does not accept keyword argument def foo(a, b, c, hsh) p hsh[:key] end foo(1, 2, 3, key: 42) # The following will work; you need to use keyword rest operator explicitly def foo(a, b, c, **hsh) p hsh[:key] end foo(1, 2, 3, key: 42) # This will cause an ArgumentError because the method call does not pass keyword argument def foo(a, b, c, key: 1) end h = {key: 42} foo(1, 2, 3, h) # The following will work; you need to use keyword rest operator explicitly def foo(a, b, c, key: 1) end h = {key: 42} foo(1, 2, 3, **h) ``` I think here is a transition path: * Ruby 2.6 (or 2.7?) will output a warning when a normal argument is interpreted as keyword argument, or vice versa. * Ruby 3.0 will use the new semantics. ---Files-------------------------------- vm_args.diff (4.19 KB) vm_args_v2.diff (4.18 KB) -- https://bugs.ruby-lang.org/