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 B8C0819E0037 for ; Sun, 27 Dec 2015 04:56:08 +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 EF083B5D828 for ; Sun, 27 Dec 2015 05:28:39 +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 0D49B18CC7AF for ; Sun, 27 Dec 2015 05:28:40 +0900 (JST) Received: from [221.186.184.76] (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id D08DB1204DA; Sun, 27 Dec 2015 05:28:38 +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 5ABD6120036 for ; Sun, 27 Dec 2015 05:28:35 +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=Z+j53U+x5qVQfbsFeQTasfYjlLc=; b=Q2TCMrXGbj28zEHAmP 1TJU6hGaLBwVgaTXpiYVfTgIrC5wyPF3giyRYzD4Mz5fBu5V3B/Es+xZPIreBpw5 qYn1x0vMyoGqBW8o8rwpFYMs43TF7VzBUEJQz92Gj8YXUKoO/GUlt0wMux0YTz3/ Jw4NZhue3BvLOUEs2G4+0hFHY= Received: by filter0481p1mdw1.sendgrid.net with SMTP id filter0481p1mdw1.8956.567EF86F1F 2015-12-26 20:28:31.37367019 +0000 UTC Received: from herokuapp.com (ec2-54-205-176-157.compute-1.amazonaws.com [54.205.176.157]) by ismtpd0005p1iad1.sendgrid.net (SG) with ESMTP id R9r40u2yTbqAqjLe2VJFGg for ; Sat, 26 Dec 2015 20:28:31.003 +0000 (UTC) Date: Sat, 26 Dec 2015 20:28:30 +0000 From: hcatlin@gmail.com To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 47093 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 11882 X-Redmine-Issue-Author: hcatlin X-Redmine-Issue-Assignee: matz X-Redmine-Sender: hcatlin 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/Ymy4QrNMhiuLXJG8OTL2vJD1yS5TIa8AGaeU/IJTzIhdRF+Ikh7MJnB95MfEJK evcDJnExVV3xvvocbPp6WF7KFZS400S7NuspTZwz7xH+QD9220apd+gldy2wY7+vGVICQTzEHeVwy+ g8lD5weAQSMSIqEuFiYmrfFKFaUJzl7M1KJ2 X-ML-Name: ruby-core X-Mail-Count: 72497 Subject: [ruby-core:72497] [Ruby trunk - Feature #11882] [Open] 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 reported by Hampton Catlin. ---------------------------------------- Feature #11882: Map or NamedMap https://bugs.ruby-lang.org/issues/11882 * 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/