Variables in ruby

variable.rb

class A
  @foo = :foo
  @@bar = :bar

  attr_reader :foo

  def foo
    @foo = :bla
  end

  def self.foo
    @foo
  end

  def self.bar
    @@bar
  end
end

class B < A
  @foo = :poo
  @@bar = :lol
end

puts "#{A.foo}, #{A.bar}, #{A.instance_variables}, #{A.class_variables}"
puts "#{B.foo}, #{B.bar}, #{B.instance_variables}, #{B.class_variables}"

a = A.new
puts "#{a.foo}, #{a.instance_variables}, #{a.class.instance_variables}, #{a.class.class_variables}"

__END__

foo, lol, [:@foo], [:@@bar]
poo, lol, [:@foo], [:@@bar]
bla, [:@foo], [:@foo], [:@@bar]
[Finished in 0.1s]