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_HELO_NONE,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 DFDCA1F4C0 for ; Fri, 18 Oct 2019 20:26:57 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 54105120A88; Sat, 19 Oct 2019 05:26:46 +0900 (JST) Received: from xtrwkhkc.outbound-mail.sendgrid.net (xtrwkhkc.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 3EDD4120998 for ; Sat, 19 Oct 2019 05:26:43 +0900 (JST) Received: by filter0034p3iad2.sendgrid.net with SMTP id filter0034p3iad2-13494-5DAA2004-61 2019-10-18 20:26:44.484159971 +0000 UTC m=+64169.631855931 Received: from herokuapp.com (unknown [3.83.29.112]) by ismtpd0024p1mdw1.sendgrid.net (SG) with ESMTP id WKXHmA2_RPWbc7u9fvPEwg for ; Fri, 18 Oct 2019 20:26:44.314 +0000 (UTC) Date: Fri, 18 Oct 2019 20:26:44 +0000 (UTC) From: shannonskipper@gmail.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 71015 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 16261 X-Redmine-Issue-Author: zverok X-Redmine-Sender: shan 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?T0jc+HUEV7CM5SiK=2FBdwdf6zPPpzUxEkATeka3QtAYogvajxBTrRjTkW2J9hNc?= =?us-ascii?Q?Ufs9iDo9Fprz7uQzyWGz7uv7LmmeDTx5=2F=2FdhkuM?= =?us-ascii?Q?xfSQXYqICgv07xPPsxIjY37WXRKyqmPVRB1KoUI?= =?us-ascii?Q?E+flxi7v5izsmOcCgdAREaDPr8iNwZJA6QgmvLs?= =?us-ascii?Q?boByvUETU3gP8Y7VYbP+9EAMN6BTblrwmfg=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 95424 Subject: [ruby-core:95424] [Ruby master Feature#16261] Enumerable#each_tuple 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 #16261 has been updated by shan (Shannon Skipper). This reminds me of a neat post showing applicatives in pictures: http://adit.io/posts/2013-04-17-functors,_applicatives,_and_monads_in_pictures.html#applicatives In Haskell: ``` [(*2), (+3)] <*> [1, 2, 3] ``` Or with this proposal in Ruby: ``` [2.:*, 3.:+].product([1, 2, 3]).each_tuple.map(&:call) ``` ---------------------------------------- Feature #16261: Enumerable#each_tuple https://bugs.ruby-lang.org/issues/16261#change-82178 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- New method proposal. Prototype code: ```ruby module Enumerable def each_tuple return to_enum(__method__) unless block_given? each { |item| yield(*item) } # unpacking possible array into several args end end ``` Supposed documentation/explanation: > For enumerable with Array items, passes all items in the block provided as a separate arguments. t could be useful if the provided block has lambda semantics, e.g. doesn't unpack arguments automatically. For example: ```ruby files = ["README.md", "LICENSE.txt", "Contributing.md"] content = [fetch_readme, fetch_license, fetch_contributing] # somehow make a content for the files files.zip(content).each_tuple(&File.:write) # writes to each file its content ``` > When no block passed, returns enumerator of the tuples: ```ruby [1, 2, 3].zip([4, 5, 6]).each_tuple.map(&:+) # => [5, 7, 9] ``` -- https://bugs.ruby-lang.org/