Class in a Class problem

ruby-talk
1

My intent is to create a class that has access to call a method in an
instantiation of another class
  
Here be dragons. Have you considered the inheritance idea? If a class *needs* access to another class's private variables, then the functionality either belongs in the same class or a child class. Whilst this is technically legal, it really doesn't bode well. If you absolutely need Class A to have exactly one instantiation of Class B you might want to consider the Singleton design pattern for class B. Which in ruby is _really_ difficult to implement...

include singleton #(or something along those lines) :slight_smile:

and for B to be a class variable of A (@@b = B.new) which, if they act like Java statics (and I think they do) the class variable has one instantiation able to be accessed from any object of the class.

e.g
class B
  def initialize()
  end

  def to_s
    "This is class #{class}"
  end
end

class A

  @@b = B.new()

  def intitialize()
    puts @@b
  end

end

But in truth, you will have to be a little less generic to get a better answer. If you can give more details of what you're trying to achieve, then please do, and I'll try and give better help.

Michael

···

denize.paul@gmail.com wrote:

However my knowledge of Ruby classes (Ok classes in general) is
somewhat lacking

The example below is a LOT simplified But I need class B to call a
method within an instantiation of class A's.

one alternative is to seperate the classes and then just do "b=B.new
(a)" but I think that looks really messy and
- I have then to check a bunch of stuff about the parameter a
- I would have a world of more hurt trying to ensure that only one B
instantiation pointed to each a

Can anyone help? Or tell me that I am doing this all wrong.

Paul

-----

class A
  class B
    def initialize()
      puts "b init"
      print_stuff()
    end
  end

  def B
    return B
  end

  def print_stuff()
    puts "here"
  end
end

a = A.new()
b = a.B.new()

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