Global dynamic method definition

ruby-talk
1

Hi,

I'm trying to code in Ruby something that looks like this, when reduced and highly simplified:

···

------------------------------------------
class B
  puts "B class init"
  @@dynamic_method_outputs = Array.new
  
  def initialize
    puts "B instance init"
  end
  
  def B.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
------------------------------------------

The output of this is:

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

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.

The only trick I could find for the moment is to use a dummy instanciation, but it is still not really clean, and prone to errors.

------------------------------------------
class B
  puts "B class init"
  @@dynamic_method_outputs = Array.new
  
  def initialize
    puts "B instance init"
    @@dynamic_method_outputs.clear
  end
  
  def B.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
D1.new

class D2 < B
  add_to_dynamic_method_output 789
end
D2.new

d1 = D1.new
d1.dynamic_method

d2 = D2.new
d2.dynamic_method
789
------------------------------------------

Output is here:

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

Does anyone have a better idea?

Philippe