Instance variable aliasing

alias_delegate.rb

require 'ostruct'
require 'delegate'
require 'json'

class Foo < Delegator
  def initialize(json)
    @ostruct = JSON.parse(json, object_class: OpenStruct)
    __setobj__(@ostruct)
  end

  protected

  def __getobj__
    @ostruct
  end

  def __setobj__(obj)
    obj.methods(false).each{ |m|
      if m.to_s[-1] != '='
        res = obj.send(m)
        if res.is_a?(OpenStruct)
          __setobj__(res)
        end
      end
      snake = m.to_s.gsub(/(.)([A-Z])/,'\1_\2').downcase.to_sym
      obj.instance_eval("alias #{snake} #{m}")
    }
  end
end

json_string = '
  {
    "firstName":"jeff",
    "lastName":"durand",
    "address": {
      "streetAddress":"22 charlotte rd",
      "zipCode":"01013"
    }
  }
'

f = Foo.new(json_string)
p f.firstName # works
p f.first_name # works
p f.address.streetAddress # works
p f.address.street_address # OOPS