class-reloading-test.rb

# the basics of class reloading in ruby
# it's all based around unloading with Module#remove_const
# then reloading with Kernel#load
# the rest is just housekeeping

require 'foo'
Foo.exclaim!
Object.instance_eval { remove_const :Foo }
load 'foo.rb'
Foo.still_there?

foo.rb

module Foo
  
  def self.exclaim!
    puts "hello, world!"
  end

  def self.still_there?
    puts "why, yes, I am!"
  end

end