add a protected static method to a class in ruby

To add a protected static method to a class in Ruby, you can use the class << self syntax to define the method within the class's singleton class, and then use the protected keyword to set the method's access level.

Here's an example:

main.rb
class MyClass
  class << self
    protected

    def my_protected_class_method
      # do something
    end
  end
end
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In this example, my_protected_class_method is defined as a protected method of the MyClass's singleton class. This means that it can only be called from within the class itself and its subclasses, but not from outside the class.

To call the protected method from within the class, you can use the self keyword:

main.rb
class MyClass
  class << self
    protected

    def my_protected_class_method
      # do something
    end
  end

  def my_method
    self.class.my_protected_class_method
  end
end
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In this example, my_method calls the protected class method using self.class, which returns the singleton class of MyClass. From there, the protected method can be called with my_protected_class_method.