回调方法应用 及 引入到模块方法应用

1： http://ruby-china.org/topics/413

module YourPlugin
  module Mixin
def xxx_attr(attr)
      attr = attr.to_s
      self.class_eval(%Q{
def #{attr}
  #...
end

def #{attr}=(value)
   #...
end
        }
      )
    end
  end
end

class Post
  include YourPlugin::Mixin
  xxx_attr :tag_list
end

2. http://quake.iteye.com/blog/448235

#plugins/your_plugin_name/lib/enum_attr.rb
moduleEnumAttr
moduleMixin
defenum_attr(attr,enums)
attr=attr.to_s
self.class_eval(%Q{
ENUMS_#{attr.upcase}=enums
validates_inclusion_ofattr,:in=>enums.map{|e|e[1]},:allow_nil=>true
def#{attr}_name
ENUMS_#{attr.upcase}.find{|option|option[1]==#{attr}}[0]unless#{attr}.nil?
end
})
end
end
end

#plugins/your_plugin_name/init.rb
require'enum_attr'
Object.send:include,EnumAttr::Mixin