From: Ruby Admirer <ruby_admirer@...>
Date: 2007-03-22T19:03:00+09:00
Subject: Re: About class methods visibility (public/private)

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Matz,
   
  First, I'm very glad that you answered my mail.
  
>Yukihiro Matsumoto <matz@ruby-lang.org> wrote:
  >> 1/ why public, protected, private methods cannot be used for defining the visibility of class methods in addition to defining the visibility of instance methods ? Is there a technical reason or a conceptual reason for this ?

>I am not sure what you mean here by "defining the visibility of class
methods in addition to defining the visibility of instance methods".
Can you elaborate?
  
 
  Sure. I wrote the following code a few days ago :
   
  class C
  def one
    puts "One"
  end
 
  def self.other_one
    puts "Other one"
  end
   
    private
    
  def two
    puts "Two"
  end
    
  def self.other_two
    puts "Other two"
  end
  #  private_class_method :other_two # added later
end
  
 
  What I basically expected is that the private method will make the class method "other_two" private as it makes private the instance method "two".
  I realized later the usefulness of the private_class_method so I added the commented line afterwards.
  What I'd like if possible is that the private method (and its friend protected and public) works also for class methods.
  
>If you want to change class method visibility, use singleton class
notation, "class <<
   
  I agree. But the public_class_method and private_class_method does the job without having to go into the singleton class.
   
   
  >>| 2/ why the protected_class_method is missing ?
>| The only methods are private_class_method and public_class_method.

>We don't have private_class_methods nor public_class_methods in Ruby.
>Are confusing with something else?
  
 
  Yes. I just mean that there is no method for making a class method protected like there are ones for making a class method private or public.
  What is missing is a protected_class_method similar as private_class_method and public_class_method.
   
   
  >>| 3/ The naming of these methods are quite confusing. Each time I read them I understand "give me the private/public class method ...". The naming is too/very close to private_methods, public_methods, ...
>>| I would prefer something like class_private, class_protected, class_public.

>What do you confuse with what? For me, class_private etc. mean nothing.

   
  You have methods like private_methods / private_instance_methods, ... returning the private methods / private instance methods of an object/class.
  private_class_method sounds like return me the private class method of ...
  This is a bit confusing.
   
  For my suggestion :
  like you have private, protected, public for defining the visibility of instance methods, you will have class_private, class_protected, class_public for the visibility of class methods.
  The prefix class_ is a hint for indicating that these methods work for class methods.
   
  
>Examining your questions before asking something is a tip to get
>useful answers.
>matz.
   
  It seems that my questions were not clear initially.
  I hope that it is now more clear.
   
   


 
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