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 85BA81F45F for ; Sun, 5 May 2019 18:48:36 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id F28E1120A04; Mon, 6 May 2019 03:48:30 +0900 (JST) Received: from o1678916x28.outbound-mail.sendgrid.net (o1678916x28.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id E06D7120A4B for ; Mon, 6 May 2019 03:48:28 +0900 (JST) Received: by filter0046p3las1.sendgrid.net with SMTP id filter0046p3las1-4796-5CCF2FFC-18 2019-05-05 18:48:28.957086757 +0000 UTC m=+858790.309157747 Received: from herokuapp.com (unknown [35.172.227.62]) by ismtpd0005p1iad1.sendgrid.net (SG) with ESMTP id 5kmZNtIURuOJAeBRKaLlbQ for ; Sun, 05 May 2019 18:48:28.997 +0000 (UTC) Date: Sun, 05 May 2019 18:48:29 +0000 (UTC) From: foonlyboy@gmail.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 68044 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 15829 X-Redmine-Issue-Author: foonlyboy X-Redmine-Sender: foonlyboy 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?C1sY0KTFJLESsrpdDIZfILysIdYN9fBoi0I2HVzpA6BgKrIsf0re1=2F2eCXb9X7?= =?us-ascii?Q?U9EvF4yYYHncsy473J0+iVzlysKDrPHSozeLvtp?= =?us-ascii?Q?j7CGTkmz=2FuGbwks6lbSAiEAES+M3TrAhO3nu9nE?= =?us-ascii?Q?ukMkr7qkTt58eVs92r0Xu+usAdlwiiSzwM3=2F+Rs?= =?us-ascii?Q?UDRoKvsNiSNiURrMsVc0qM3C9uj1c3CnXBA=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 92561 Subject: [ruby-core:92561] [Ruby trunk Feature#15829] Object#then_if(condition){} 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 #15829 has been updated by foonlyboy (Eike Dierks). A (somehow contrived) example: ``` ruby [1,2,3,4,5].map{|n| n.then_if(n.even?){'even'}} => [1, "even", 3, "even", 5] ``` ---------------------------------------- Feature #15829: Object#then_if(condition){} https://bugs.ruby-lang.org/issues/15829#change-77924 * Author: foonlyboy (Eike Dierks) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- I'd like to propose some sugar to Object#then There should be Object#then_if(condition, &block) The block should only be applied when the condition is true, otherwise the object should be returned without applying the block. Rationale: I frequently use Object#then with Rails to extend queries like this: ``` foo.then {|query| if(condition) query.where(zip:zap) else query end } ``` by using the proposed Object#then_if the example could be simplified to: ``` foo.then_if(condition) {|query| query.where(zip:zap) } ``` I believe that this also applies to a lot of other use cases, i.e. only applying some transformation if some condition is true, but otherwise leaving the result untouched. -- https://bugs.ruby-lang.org/