method_spells_const_get_n_set.rb

Book = "Eloquent Ruby"
Module.const_get(:Book) #=> "Eloquent Ruby"
Module.const_set(:Book, "Ruby Science") #=> "Ruby Science"
Module.const_get(:Book) #=> "Ruby Science"


class Person
  def name
    "Sword Master"
  end
end

person_class = Module.const_get(:Person) #=> Person
p = person_class.new
p.name #=> "Sword Master"

Module.const_set(:Trainer, Class.new { attr_accessor :stack })
trainer_class = Module.const_get(:Trainer) #=> Trainer
trainer = trainer_class.new
trainer.stack = "Ruby"
trainer.stack #=> "Ruby"