Question

I want to be able to write a code like below:

MyModule::MyClass.configure do |item|
  item.var1 = 'dsads'
  item.var2 = 'dsadsa'
  item.var3 = 'fdsfdsfd'
end

Well, I define a module and a class within it:

module MyModule
 class MyClass
 end
end

…and what should I do further?

Answer 1

If you want to do configuration, then I would recommend that you use a Singleton class, like this:

require 'singleton'
module MyModule
 class MyClass
   include Singleton
 end
end

Then you will need to define the configure method on this:

require 'singleton'
module MyModule
 class MyClass
   include Singleton
   def self.configure
     yield(self)
   end
 end
end

yield will evaluate the block within the context of the class, meaning that any methods called on the block object will be called on the class object.

Then for each method you call inside the configure block, you will need a corresponding method definition inside the class. You can do this by defining the methods manually:

 class MyClass
   def self.var1=(value)
     @var1 = value
   end

   def self.var1
     @var1
   end 
 end

Or, you can use attr_accessor:

 class MyClass
   class << self
     attr_accessor :var1
   end
 end

To get the values back out, just do this:

 MyMoudle::MyClass.var1

If you don’t want to use a singleton, then change the class represented MyClass to be a module instead.