Global dynamic method definition

ruby-talk
1

As the code suggest, what I except is:

B class init
B instance init
123
456
B instance init
789

In other words, the global @@dynamic_method_outputs is not
cleared between D1 and D2 class definitions.

Class variables are shared between a class and all its subclasses. You
want an instance variable of the class itself:

class B
  puts "B class init"
  def self.dynamic_method_outputs
    @dynamic_method_outputs ||=
  end
  
  def initialize
    puts "B instance init"
  end
  
  def self.add_to_dynamic_method_output(val)
    dynamic_method_outputs << val
    
    method_def = "def dynamic_method() "
    
    dynamic_method_outputs.each do |v|
      method_def << "puts #{v} \n"
    end
    
    method_def << "end"
    
    self.class_eval method_def
  end
end
    
class D1 < B
  add_to_dynamic_method_output 123
  add_to_dynamic_method_output 456
end

class D2 < B
  add_to_dynamic_method_output 789
end

d1 = D1.new
d1.dynamic_method

d2 = D2.new
d2.dynamic_method

#=> B class init
#=> B instance init
#=> 123
#=> 456
#=> B instance init
#=> 789

···

From: Philippe Lang [mailto:philippe.lang@attiksystem.ch]