I thought about the best way to create a ValueObject in Ruby

module ValueObjectable
  def initialize(args)
    super(args)
    freeze
  end
end

class Location < Struct.new(:country, :city, keyword_init: true)
  include ValueObjectable
end

##Feature##
# 1.Can be initialized with Hash like OpenStruct
tokyo = Location.new(country: 'Japan', city: 'Tokyo')
=> #<struct Location country="Japan", city="Tokyo">

# 2.You don't have to define the comparison logic yourself
fukuoka = Location.new(country: 'Japan', city: 'Fukuoka')
tokyo == fukuoka
=> false

# 3.Value is unchanged
tokyo.country = 'U.S'
FrozenError: can't modify frozen Location

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