问合并值后更新多个哈希键

EN

class ProxyObject
  # thanks to https://alisdair.mcdiarmid.org/invisible-proxies-with-ruby/
  instance_methods.each do |m|
    undef_method(m) unless m =~ /(^__|^nil\?$|^send$|^object_id$)/
  end

  attr_accessor :target

  def initialize(target)
    @target = target
  end

  def respond_to?(symbol, include_priv=false)
    @target.respond_to?(symbol, include_priv)
  end

  private def method_missing(method, *args, &block)
    @target.send(method, *args, &block)
  end
end

a = 1
b = 10
a_proxy = ProxyObject.new(a)
b_proxy = ProxyObject.new(b)
a_proxy.class                   # verify how well they masquerade
# => Integer
hash = 10.times.map { |i| [i + 1, i < 5 ? a_proxy : b_proxy] }.to_h
# => {1=>1, 2=>1, 3=>1, 4=>1, 5=>1, 6=>10, 7=>10, 8=>10, 9=>10, 10=>10} 
hash.values.sum()               # confirm it behaves exactly like a number
# => 55
b_proxy.target = a_proxy.target # switch reference
hash
# => {1=>1, 2=>1, 3=>1, 4=>1, 5=>1, 6=>1, 7=>1, 8=>1, 9=>1, 10=>1}
hash.values.sum()               # confirm the reference is changed
# => 10