我见过最清楚的解释class_eval 和 instance_eval_Ruby

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我见过最清楚的解释class_eval 和 instance_eval

2013/5/19 14:49:16 夜鸣猪程序员俱乐部我要评论(0)

摘要：忘了，看一次就能回忆起来classA#defsheregotoAputsself#=>Aclass<<self#defsheregotoA'seigenclassendendA.class_evaldo#defsheregotoAendA.instance_evaldo#defsheregotoA'seigenclassends="HelloWorld"class<<s#defsheregotos'seigenclassend
标签：instance class

忘了，看一次就能回忆起来

class="ruby" name="code">
class A
  # defs here go to A
  puts self  # => A
  class << self
     #defs here go to A's eigenclass
  end
end

A.class_eval do
  #defs here go to A
end

A.instance_eval do
  #defs here go to A's eigenclass     
end

s = "Hello World"

class << s
  #defs here go to s's eigenclass
end