Create dynamic attribute in the Struct instance

Question

Is it possible to create attribute dynamicaly in the Struct instance?

class Person < Struct.new(:name)
end

p = Person.new("Bilbo")
p[:surname] = "Jenkins" # does not work

Answer 1

You could use an OpenStruct:

require 'ostruct'

p = OpenStruct.new(name: "Bilbo")
p[:surname] = "Jenkins"

p.surname # => "Jenkins"

Answer 2

You can define new methods on your Person class by doing this:

Person.send(:define_method, :surname){@surname}
Person.send(:define_method, :surname=){|x|@surname=x}

I prefer define_method instead of instance_eval because I try to omit eval when possible.