Structに読み取り専用のmemberがほしい.rb

sample.rb

Person = Struct.new(:name, :age, :hoge, keyword_init: true) do
  def initialize(**kw)
    raise 'hoge は指定できへんで' if kw[:hoge]
    super
    self.hoge = :xxx
    undef :hoge=
  end
end

person = Person.new(name: 'foo', age: 10)
pp person.to_h # => {:name=>"foo", :age=>10, :hoge=>:xxx}