typed_struct.rb

class Person < TypedStruct[first_name: String, last_name: String]
  def full_name
    "#{first_name} #{last_name}"
  end
end

class Person < TypedStruct[first_name: String,
                           last_name: String,
                           age: [Integer, :optional]]
  def full_name
    "#{first_name} #{last_name}"
  end
end

class Person < TypedStruct
  field :first_name, String
  field :last_name, String
  field :age, Integer, :optional
end

Person.new('Luke', 'Morton')
Person.new(first_name: 'Luke', last_name: 'Morton')
Person.new(first_name: 12, last_name: 'Morton') # => raises TypedStruct::TypeError
Person.new(first_name: 'Luke') # => raises TypedStruct::FieldMissingError