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 (smtp.nagaokaut.ac.jp [133.44.2.24]) by blade.nagaokaut.ac.jp (Postfix) with ESMTP id 5EB8419E0053 for ; Sat, 30 Jan 2016 12:34:35 +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 A6942B5D86B for ; Sat, 30 Jan 2016 13:08:41 +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 0D53A18CC7E2 for ; Sat, 30 Jan 2016 13:08:41 +0900 (JST) Received: from [221.186.184.76] (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id D8DBA1204E9; Sat, 30 Jan 2016 13:08:40 +0900 (JST) X-Original-To: ruby-core@ruby-lang.org Delivered-To: ruby-core@ruby-lang.org Received: from o2.heroku.sendgrid.net (o2.heroku.sendgrid.net [67.228.50.55]) by neon.ruby-lang.org (Postfix) with ESMTPS id 6E9931204DF for ; Sat, 30 Jan 2016 13:08:36 +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=RwzHJKwd4o/KMPsvK2un6opckm8=; b=HW0pZ3QQVe8VkOU3gO FvznvgWtbXHI7PLTLAOx/JT3G3ILUJJ7LzmmHSaofb21BtPQ0/mMmhAN1KNt4fUw m31q54aGhEkZFkDF0kyz4mhFEz4wfQJnYvCLJQxmV7YBpeHi5qKcd1s8zba76+j8 H1glV+YPkrvySldrS96HHboOI= Received: by filter0632p1mdw1.sendgrid.net with SMTP id filter0632p1mdw1.12353.56AC374023 2016-01-30 04:08:32.611206283 +0000 UTC Received: from herokuapp.com (ec2-54-158-44-162.compute-1.amazonaws.com [54.158.44.162]) by ismtpd0003p1iad1.sendgrid.net (SG) with ESMTP id FRI1AMAtQpCO_G1gY1N1nw Sat, 30 Jan 2016 04:08:32.720 +0000 (UTC) Date: Sat, 30 Jan 2016 04:08:32 +0000 From: andrew@avit.ca To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 48191 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 11882 X-Redmine-Issue-Author: hcatlin X-Redmine-Issue-Assignee: matz X-Redmine-Sender: avit 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/Ymy4QrNMhiuLXJG8OTL2vJD1yS5yHk+jW7ZDRcMFk5MXOhZYOSz/vjNeqJ5xe1 ZkOB3Td/AiEuuadtDNVbDkKIqlSRbBAAuIuW/sUeVg2Pu4Ow9p8ajSNO57BxI6OxmpFq86epqekNie 2QFwhxWX57CC/HuZmQhZ8XVnKqL1JMjqNZ3N X-ML-Name: ruby-core X-Mail-Count: 73596 Subject: [ruby-core:73596] [Ruby trunk - Feature #11882] Map or NamedMap 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 #11882 has been updated by Andrew Vit. Robert A. Heiler wrote: > I concur with Hampton Catlin for the most part (save for the > name "Map", that is not a good name IMO). "Dict" is another possible name. How would this proposal handle other key types? Should `obj[1] = 'a'` convert using `to_s` or raise an error? ---------------------------------------- Feature #11882: Map or NamedMap https://bugs.ruby-lang.org/issues/11882#change-56791 * Author: Hampton Catlin * Status: Open * Priority: Normal * Assignee: Yukihiro Matsumoto ---------------------------------------- Hash is one of the best features of Ruby. I remember being so pleased when I first learned Ruby to find out that *anything* could be a key and that you could do some really clever things with scripts, if you key of non-traditional elements. However, like many people, 10 years into using Ruby, I still am writing code to cast around symbols to strings and strings to symbols, just to use Hash as a more traditional dictionary, keyed with string-like values. And, explaining to a junior programmers why they broke the code by using a key of a different type... it's not the most elegant thing to have to explain over and over. Several proposals exist for how to deal with this, and all have been rejected... however it doesn't seem like it's for essential reasons, more technical or syntactic issues. Coming up with syntax is something I quite enjoy (Sass/Haml), so I thought I'd make a pitch for it. Requirements: 1) Doesn't break existing code 2) Doesn't totally destroy the parser 3) Seems simple to differentiate 4) Clear upgrade path My proposal is to introduce an entirely different type of Hash, called a Map (or NamedMap, if that's too ambiguous), that requires a string-like key. There are no other types of keys allowed on this Hash, other than either strings or symbols. Internally, each key would be considered a symbol only. ~~~ map = Map.new(a: 2, b: 3) map["a"] #=> 2 map[:a] #=> 2 ~~~ Already, we're better than HashWithIndifferentAccess, as it's clearly a bit easier to type. ;) What about a literal syntax? ~~~ map = {{a: 2}} empty_map = {{}} ~~~ As far as I can tell in the Ruby-syntax style, this should be pretty easy to distinguish syntactically from both a regular hash literal and a block. Further, as almost every method's option hash is string-keyed, you could easily define this. ~~~ def my _method(arg1, options = {{}}) end ~~~ Immediately, you could deal with your options hash, and not have to stress about if the end user has passed in strings or symbols into the options. It would be trivial to create a Map polyfill for most libraries to start using the non-literal version right away, as it would basically be HashWithIndifferentAccess, except we need to guarantee that the keys are string-like. So, to sum up, we avoid the 'breaking other people's existing code' by introducing a new data-type, the literal syntax (I think) should be fairly easy to implement, and it makes a very natural keyed data object (e.g. Javascript Objects) and brings that to Ruby. -- https://bugs.ruby-lang.org/