Ruby Module and Class

module_and_class.rb

module MyModule
  @@module_v = 'module variable'
  @instance_v = 'instance variable'

  def set_m(value)
    @@module_v = value
  end

  def print_m
    p @@module_v
  end

  def set_i(value)
    @instance_v = value
  end

  def print_i
    p @instance_v
  end
end 

class MyClass
  include MyModule

  @instance_v = 'piyo'

  def my_set_i(value)
    @instance_v = value
  end
end


i = MyClass.new
i.print_m
i.print_i
i.set_i 'hoge'
i.print_i
i.my_set_i 'hogefuga'
i.print_i

include MyModule
MyModule.print_i
print_i

result.txt

$ ruby test.rb
"module variable"
nil
"hoge"
"hogefuga"
"instance variable"
nil