如何使用哈希键作为类的方法? [英] How do I use hash keys as methods on a class?

问题描述

我有一个课程和一个哈希.如何让hash的成员动态成为类上以key为方法名的方法?

I have a class and a hash. How can I get the members of the hash to dynamically become methods on the class with the key as the method name?

class User
  def initialize
    @attributes = {"sn" => "Doe", "givenName" => "John"}
  end
end

例如，我希望能够有以下输出 Doe:

For example, I would like to be able to have the following output Doe:

u = User.new
puts u.sn

推荐答案

def method_missing(name, *args, &blk)
  if args.empty? && blk.nil? && @attributes.has_key?(name)
    @attributes[name]
  else
    super
  end
end

说明:如果你调用一个不存在的方法，method_missing 将被调用，方法名作为第一个参数，后跟提供给方法的参数和块(如果有的话).

Explanation: If you call a method, which does not exist, method_missing is invoked with the name of the method as the first parameter, followed by the arguments given to the method and the block if one was given.

在上面我们说如果一个没有定义的方法被调用时没有参数也没有块，并且散列中有一个以方法名称作为键的条目，它将返回该条目的值.否则它会照常进行.

In the above we say that if a method, which was not defined, is called without arguments and without a block and the hash has an entry with the method name as key, it will return the value of that entry. Otherwise it will just proceed as usual.

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