ruby - 在 Ruby 中创建 Expando 对象

Question

有没有更好的方法来编写这个 Expando 类？它的编写方式不起作用。我正在使用 Ruby 1.8.7

起始代码引用自https://gist.github.com/300462/3fdf51800768f2c7089a53726384350c890bc7c3

class Expando
    def method_missing(method_id, *arguments)
        if match = method_id.id2name.match(/(\w*)(\s*)(=)(\s*)(\.*)/)
              puts match[1].to_sym # think this was supposed to be commented 
              self.class.class_eval{ attr_accessor match[1].to_sym } 
              instance_variable_set("#{match[1]}", match[5])
        else
              super.method_missing(method_id, *arguments)
        end  
    end    
end

person = Expando.new 
person.name = "Michael"
person.surname = "Erasmus"
person.age = 29 

Answer 1

最简单的写法就是根本不写! :) 请参阅 OpenStruct类，包含在标准库中:

require 'ostruct'

record = OpenStruct.new
record.name    = "John Smith"
record.age     = 70
record.pension = 300

不过，如果我要写的话，我会这样做:

# Access properties via methods or Hash notation
class Expando
  def initialize
    @properties = {}
  end
  def method_missing( name, *args )
    name = name.to_s
    if name[-1] == ?=
      @properties[name[0..-2]] = args.first
    else
      @properties[name]
    end
  end
  def []( key )
    @properties[key]
  end
  def []=( key,val )
    @properties[key] = val
  end
end

person = Expando.new
person.name = "Michael"
person['surname'] = "Erasmus"
puts "#{person['name']} #{person.surname}"
#=> Michael Erasmus