Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!aioe.org!feeder.news-service.com!de-l.enfer-du-nord.net!feeder2.enfer-du-nord.net!talisker.lacave.net!lacave.net!not-for-mail From: 7stud -- Newsgroups: comp.lang.ruby Subject: Re: What do you do when you need to attach data to an object instance? Date: Sat, 16 Apr 2011 12:14:23 -0500 Organization: Service de news de lacave.net Lines: 39 Message-ID: <7b5e8d93ddba3dc3daa51fd319e3d800@ruby-forum.com> References: <6fce5b6386258c51794d0b55b63e1ed6@ruby-forum.com> <41c1bcee810455547ca7d7844c1113d2@ruby-forum.com> NNTP-Posting-Host: bristol.highgroove.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Trace: talisker.lacave.net 1302974096 79801 65.111.164.187 (16 Apr 2011 17:14:56 GMT) X-Complaints-To: abuse@lacave.net NNTP-Posting-Date: Sat, 16 Apr 2011 17:14:56 +0000 (UTC) In-Reply-To: <41c1bcee810455547ca7d7844c1113d2@ruby-forum.com> X-Received-From: This message has been automatically forwarded from the ruby-talk mailing list by a gateway at comp.lang.ruby. If it is SPAM, it did not originate at comp.lang.ruby. Please report the original sender, and not us. Thanks! For more details about this gateway, please visit: http://blog.grayproductions.net/categories/the_gateway X-Mail-Count: 381707 X-Ml-Name: ruby-talk X-Rubymirror: Yes X-Ruby-Talk: <7b5e8d93ddba3dc3daa51fd319e3d800@ruby-forum.com> Xref: x330-a1.tempe.blueboxinc.net comp.lang.ruby:3015 Kevin Mahler wrote in post #993207: > 7stud -- wrote in post #993115: >> Kevin Mahler wrote in post #992907: >>> >>> def extend_accessor(obj, name) >>> obj.singleton_class.module_eval { attr_accessor name } >>> obj >>> end >>> >> >> Hey, now. obj.singleton_class is a class, so how about using the >> synonym class_eval(): >> >> obj.singleton_class.class_eval { attr_accessor name } > > A class is a module, but a module is not a class. > Yes, of course. > Class.new.is_a? Module #=>true > Module.new.is_a? Class #=>false > > Because module_eval and class_eval are aliases, class_eval can be > called on a module, a situation which is at worst wrong It certainly isn't "wrong"--ruby allows it. > and at best > confusing. module_eval can never be wrong or confusing. Not a hard > choice. I thought using module_eval was confusing in your code, and that was why I suggested class_eval(). -- Posted via http://www.ruby-forum.com/.