From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: poffice@blade.nagaokaut.ac.jp Delivered-To: poffice@blade.nagaokaut.ac.jp Received: from kankan.nagaokaut.ac.jp (kankan.nagaokaut.ac.jp [133.44.2.24]) by blade.nagaokaut.ac.jp (Postfix) with ESMTP id 73AD219C0020 for ; Fri, 23 Oct 2015 01:18:31 +0900 (JST) Received: from voscc.nagaokaut.ac.jp (voscc.nagaokaut.ac.jp [133.44.1.100]) by kankan.nagaokaut.ac.jp (Postfix) with ESMTP id EE720B5D8FC for ; Fri, 23 Oct 2015 01:45:42 +0900 (JST) Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by voscc.nagaokaut.ac.jp (Postfix) with ESMTP id F12EE952439 for ; Fri, 23 Oct 2015 01:45:40 +0900 (JST) Received: from [221.186.184.76] (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id CC0B91204C6; Fri, 23 Oct 2015 01:45:41 +0900 (JST) X-Original-To: ruby-core@ruby-lang.org Delivered-To: ruby-core@ruby-lang.org Received: from o10.shared.sendgrid.net (o10.shared.sendgrid.net [173.193.132.135]) by neon.ruby-lang.org (Postfix) with ESMTPS id 522FF1204BD for ; Fri, 23 Oct 2015 01:45:38 +0900 (JST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.me; h=from:to:references:subject:mime-version:content-type:content-transfer-encoding:list-id; s=smtpapi; bh=mm5UOwwVxaaPDDEtrqodMJMATLE=; b=NY8FCXEgHMzXSnStQN zysWOqfLgJHH05UintK/MySGGKrphDg8FIrc7RSyyOB4SvUyJsFe2j3olchKZSeC 8V9ubDfn/DeNG9jleDf4OJB+FctoWJcVOfutvh6T5Z+mWSBkK0bC2zLzms2GYK/x AelWyJ05u8wj7P2lk1zsnNXyg= Received: by filter0457p1mdw1.sendgrid.net with SMTP id filter0457p1mdw1.25366.562912AB25 2015-10-22 16:45:31.228380996 +0000 UTC Received: from herokuapp.com (ec2-107-21-135-130.compute-1.amazonaws.com [107.21.135.130]) by ismtpd0005p1iad1.sendgrid.net (SG) with ESMTP id A9Y2n6rgTHiR4Miw5G_vHQ for ; Thu, 22 Oct 2015 16:45:30.845 +0000 (UTC) Date: Thu, 22 Oct 2015 16:45:30 +0000 From: merch-redmine@jeremyevans.net To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Redmine-MailingListIntegration-Message-Ids: 45786 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 11537 X-Redmine-Issue-Author: hsbt X-Redmine-Issue-Assignee: matz X-Redmine-Sender: jeremyevans0 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: ync6xU2WACa70kv/Ymy4QrNMhiuLXJG8OTL2vJD1yS7z9s3RWiJwinMiabMcpeab+S7e8lmOPdKl0F iKv3WKzQMR4npvzfSD/GY7baJqC5FMUb9J+kenJkl/QMnzBIfoSTfWl4ZHgI13Mue7x7zu/efzRaGl hEomV4W2R9gcFj5mkYNsuVysZHEQHk2394rF X-ML-Name: ruby-core X-Mail-Count: 71160 Subject: [ruby-core:71160] [Ruby trunk - Feature #11537] Introduce "Safe navigation operator" 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: , Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #11537 has been updated by Jeremy Evans. Tom Reznick wrote: > Hi, > > I think we may have found some unexpected behavior with the `.?` operator. > > If I call the following: > > s = Struct.new(:x) > o = s.new() > o.x #=> nil > o.x.nil? #=> true > o.x.?nil? #=> nil > o.x.kind_of?(NilClass) #=> true > o.x.?kind_of?(NilClass) #=> nil > o.x.methods.include?(:nil?) #=> true > > > While it's arguably a bit peculiar to try to check that `nil` is `nil`, in a `nil`-safe way, `.?kind_of?(NilClass)` could reasonably return `true`. I think it's completely expected that `nil.?kind_of?(NilClass)` returns `nil` and not `true`. The whole point of `.?` is to return `nil` without calling the method if the receiver is `nil`. I'm not sure if `.?` is a good idea syntax-wise, but if you are going to have it, it shouldn't have special cases for specific methods. ---------------------------------------- Feature #11537: Introduce "Safe navigation operator" https://bugs.ruby-lang.org/issues/11537#change-54533 * Author: Hiroshi SHIBATA * Status: Closed * Priority: Normal * Assignee: Yukihiro Matsumoto ---------------------------------------- I sometimes write following code with rails application: ```ruby u = User.find(id) if u && u.profile && u.profile.thumbnails && u.profiles.thumbnails.large ... ``` or ```ruby # Use ActiveSupport if u.try!(:profile).try!(:thumbnails).try!(:large) ... ``` I hope to write shortly above code. Groovy has above operator named "Safe navigation operator" with "`?.`" syntax. Ruby can't use "`?.`" operator. Can we use "`.?`" syntax. like this: ```ruby u = User.find(id) u.?profile.?thumbnails.?large ``` Matz. How do you think about this? -- https://bugs.ruby-lang.org/