module,class_eval,extend

http://giantrobots.thoughtbot.com/2008/6/2/slides-from-railsconf
http://www.ruby-doc.org/core/classes/Object.html#M000337
<br />class Book < ActiveRecord::Base<br /> include TestModule<br /><br /> want_lala :lake # 為啥要這樣, 用method 去生其他的method<br />end<br />
<br />module TestModule<br /> def self.included(klass)<br /> #===== 1 ===== 三種方法都可以<br /> klass.extend ClassMethods<br /> #===== 1 =====<br /><br /> #==== 2 =====<br /> class << klass<br /> def want_lala(name)<br /> puts "#{name} lalala"<br /> end<br /> end<br /> #===== 2 =====<br /><br /> #===== 3 =====<br /> klass.class_eval do<br /> def klass.want_lala(name)<br /> puts "#{name} lalala"<br /> end<br /> end<br /> #===== 3 =====<br /> end<br /><br /> module ClassMethods<br /> def want_lala(name)<br /> puts "#{name} lalala"<br /> end<br /> end<br />end<br />