accessing_class_instance_variables_from_instance_methods.rb

# Instance methods can only access class-level instance variables via accessor methods (which are themselves class-level methods).
# Here's a demonstration of a more complex situation (in which the instance method in question comes from a mix-in module)
# that illustrates the same principle.

module M
  def f
    puts self.class.a
  end
end

class C
  include M

  @a = 'Ca'

  class << self
    attr_reader :a
  end
end

puts 'value below should be "Ca"'
C.new.f