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 43DA119C03BF for ; Tue, 24 Nov 2015 08:54:21 +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 E5D8AB5D93D for ; Sat, 21 Nov 2015 00:35:04 +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 6971D18CC7B8 for ; Sat, 21 Nov 2015 00:35:05 +0900 (JST) Received: from [221.186.184.76] (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 2E575120458; Sat, 21 Nov 2015 00:35:03 +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 7C42412003B for ; Sat, 21 Nov 2015 00:34:59 +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=hdfL4gNBT4a43i8VvsK/j6l9zBo=; b=ESKtz/2I5BhhKPj6+R 1W+0hwNYt1ktkBr7HxJiJpiDCTgd2Ravd4Voj+E/1JhOoSiTjSW5XsgIxUcOqk7F jV7nlEk28e3GQZQ0qB8s0naPO7j+TV/QDpUARIbLzS2+8nwbWwDREfdcBEquHbmn nZFlcLRjBOWZ1Mn0lSaYTYijE= Received: by filter0504p1mdw1.sendgrid.net with SMTP id filter0504p1mdw1.24550.564F3D9B1B 2015-11-20 15:34:51.262841197 +0000 UTC Received: from herokuapp.com (ec2-50-17-29-76.compute-1.amazonaws.com [50.17.29.76]) by ismtpd0006p1iad1.sendgrid.net (SG) with ESMTP id MeVpiucAQEKXCMSS7-O7mA Fri, 20 Nov 2015 15:34:51.156 +0000 (UTC) Date: Fri, 20 Nov 2015 15:34:51 +0000 From: from-ruby-lang@serversnab.ru 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: 46276 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 10984 X-Redmine-Issue-Author: olivierlacan X-Redmine-Issue-Assignee: akr X-Redmine-Sender: cvss 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/Ymy4QrNMhiuLXJG8OTL2vJD1yS6uqH3BegDAfCRwrgAK8gowlqkcOzTP9Finxd qfMkblUDOLnkIRhLIpEGAucKRnpEeYc/6XwwMKCHn08rervv+iNxv0jkGvZHqFJWoz7kr0gqUV234V ttko91oNUFQ1LGTUr2b6o3K4yihzMKpQ32VR X-SendGrid-Contentd-ID: {"test_id":"1448033692"} X-ML-Name: ruby-core X-Mail-Count: 71609 Subject: [ruby-core:71609] [Ruby trunk - Bug #10984] Hash#contain? to check whether hash contains other hash 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 #10984 has been updated by Cyril Vechera. I second Ilya's opinion regarding partially ordered sets. But propose to implement the comparision similiar to classes - Hash and Class both satisfies reflexive, antisymmetric, and transitive relations. So like the Class, Hash can implement <=>, returning nil on noncomparable argument. Take a look on classes: 
class A; end
class B; end
class BB < B; end
How they are comparing: 
> A < B
 => nil
> B < BB
 => false
> BB < B
 => true
> A <=> B
 => nil
> B <=> BB
 => 1
---------------------------------------- Bug #10984: Hash#contain? to check whether hash contains other hash https://bugs.ruby-lang.org/issues/10984#change-54993 * Author: Olivier Lacan * Status: Closed * Priority: Normal * Assignee: Akira Tanaka * ruby -v: * Backport: ---------------------------------------- Comparing hashes seems like a common practice but there currently isn't a method to ask a hash instance whether it includes another hash instance. The most intuitive method to reach for would be `Hash#include?` but it is in fact an alias to `Hash#has_key?` What I'm looking for can be achieved with: ~~~ class Hash def contain?(other) self.merge(other) == self end end ~~~ Here's a simple demo of `#contain?` in use: ~~~ { a: true, b: false }.contain?({ a: true}) # => true { a: true, b: false }.contain?({ b: false}) # => true { a: true, b: false }.contain?({ a: false}) # => false { a: true, b: false }.contain?({ c: true}) # => false ~~~ One important note is that this method is *not checking for nested hash matches*. This may need to be addressed when the parameters include a nested hash perhaps. Thanks to Terence Lee's help, nobu created a patch for this feature last year. I've only modified the name of the method from [his original patch](https://gist.github.com/nobu/dfe8ba14a48fc949f2ed) and attached it to this issue. ---Files-------------------------------- Hash#contain_.patch (2.22 KB) -- https://bugs.ruby-lang.org/