i think self.method just like class method,so if i want to define it as a private method,i should use private_class_method :my_method but i found follow code in < <Agile Web Development with Rails>> private def self.hash_password(password) Digest::SHA1.hexdigest(password) end just a mistake or there have some thing which i cannot get? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
I''ve never used private_class_method but based on the Ruby API it
should do what you want. The agile example will work too, and is
probably a bit more convenient if you have more than one private
method because the private declaration applies to everything that
comes after it.
I always group my class methods in a "class << self" block and
then
put private class methods at the end of that block like this:
class Foo
class << self
def some_public_class_method
....
end
private
def some_private_class_method
...
end
end
end
Aaron
On Jan 16, 8:41 pm, Vincent
<kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> i think self.method just like class method,so if i want to define it
> as a private method,i should use
>
> private_class_method :my_method
>
> but i found follow code in < <Agile Web Development with
Rails>>
>
> private
> def self.hash_password(password)
> Digest::SHA1.hexdigest(password)
> end
>
> just a mistake or there have some thing which i cannot get?
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but I test follow code ------------ class Foo private def self.say_hello p ''Hello'' end end class Bar def say Foo::say_hello end end Bar.new.say ----------------------- it''s works and puts ''Hello'',private in class Foo seems useless i try re-test it use private_class_method and get ''Test.rb:11:in `say'': private method `say_hello'' called for Foo:Class (NoMethodError)'' why this happen? On Jan 17, 3:11 pm, Aaron <baldw...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I''ve never used private_class_method but based on the Ruby API it > should do what you want. The agile example will work too, and is > probably a bit more convenient if you have more than one private > method because the private declaration applies to everything that > comes after it. > > I always group my class methods in a "class << self" block and then > put private class methods at the end of that block like this: > > class Foo > class << self > def some_public_class_method > .... > end > > private > def some_private_class_method > ... > end > end > end > > Aaron > > On Jan 16, 8:41 pm, Vincent <kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > i think self.method just like class method,so if i want to define it > > as a private method,i should use > > > private_class_method :my_method > > > but i found follow code in < <Agile Web Development with Rails>> > > > private > > def self.hash_password(password) > > Digest::SHA1.hexdigest(password) > > end > > > just a mistake or there have some thing which i cannot get?--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
I ran your test code and was surprised to see that the private declaration didn''t apply to the class method. I guess private only applies to instance methods. So that leaves "private_class_method" and a "class << self" block as the two ways to make class methods private. Aaron On Jan 17, 1:08 am, Vincent <kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> but I test follow code > ------------ > class Foo > private > def self.say_hello > p ''Hello'' > end > end > > class Bar > def say > Foo::say_hello > end > end > > Bar.new.say > ----------------------- > it''s works and puts ''Hello'',private in class Foo seems useless > i try re-test it use private_class_method and get > ''Test.rb:11:in `say'': private method `say_hello'' called for Foo:Class > (NoMethodError)'' > > why this happen? > > On Jan 17, 3:11 pm, Aaron <baldw...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > I''ve never used private_class_method but based on the Ruby API it > > should do what you want. The agile example will work too, and is > > probably a bit more convenient if you have more than one private > > method because the private declaration applies to everything that > > comes after it. > > > I always group my class methods in a "class << self" block and then > > put private class methods at the end of that block like this: > > > class Foo > > class << self > > def some_public_class_method > > .... > > end > > > private > > def some_private_class_method > > ... > > end > > end > > end > > > Aaron > > > On Jan 16, 8:41 pm, Vincent <kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > i think self.method just like class method,so if i want to define it > > > as a private method,i should use > > > > private_class_method :my_method > > > > but i found follow code in < <Agile Web Development with Rails>> > > > > private > > > def self.hash_password(password) > > > Digest::SHA1.hexdigest(password) > > > end > > > > just a mistake or there have some thing which i cannot get?--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
so, the demo code in <<agile>> was wrong? I hava another question,If i keep class methods private via private_class_method method,I can not invoke these methods see this --------------------------- class Test def say Test::say_hello end def self.say_hello p ''Hello'' end private_class_method :say_hello end Test.new.say ---------------------- run above code will get follow error message Test.rb:4:in `say'': private method `say_hello'' called for Test:Class (NoMethodError) How should I do can both make class methods are private and can be invoked On Jan 18, 12:15 am, Aaron <baldw...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I ran your test code and was surprised to see that the private > declaration didn''t apply to the class method. I guess private only > applies to instance methods. So that leaves "private_class_method" > and a "class << self" block as the two ways to make class methods > private. > > Aaron > > On Jan 17, 1:08 am, Vincent <kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > but I test follow code > > ------------ > > class Foo > > private > > def self.say_hello > > p ''Hello'' > > end > > end > > > class Bar > > def say > > Foo::say_hello > > end > > end > > > Bar.new.say > > ----------------------- > > it''s works and puts ''Hello'',private in class Foo seems useless > > i try re-test it use private_class_method and get > > ''Test.rb:11:in `say'': private method `say_hello'' called for Foo:Class > > (NoMethodError)'' > > > why this happen? > > > On Jan 17, 3:11 pm, Aaron <baldw...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > I''ve never used private_class_method but based on the Ruby API it > > > should do what you want. The agile example will work too, and is > > > probably a bit more convenient if you have more than one private > > > method because the private declaration applies to everything that > > > comes after it. > > > > I always group my class methods in a "class << self" block and then > > > put private class methods at the end of that block like this: > > > > class Foo > > > class << self > > > def some_public_class_method > > > .... > > > end > > > > private > > > def some_private_class_method > > > ... > > > end > > > end > > > end > > > > Aaron > > > > On Jan 16, 8:41 pm, Vincent <kaizen....-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > > i think self.method just like class method,so if i want to define it > > > > as a private method,i should use > > > > > private_class_method :my_method > > > > > but i found follow code in < <Agile Web Development with Rails>> > > > > > private > > > > def self.hash_password(password) > > > > Digest::SHA1.hexdigest(password) > > > > end > > >> > just a mistake or there have some thing which i cannot get?--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
> --------------------------- > class Test > > def say > Test::say_hello > end > > def self.say_hello > p ''Hello'' > end > > private_class_method :say_hello > end > > Test.new.say > ---------------------- > run above code will get follow error message > Test.rb:4:in `say'': private method `say_hello'' called for Test:Class > (NoMethodError) > How should I do can both make class methods are private and can be > invokedYou can''t access the private class method from an object instance because they are in different classes. Every ruby object has what is called a singleton class that contains per-object attributes. See Chapter 24 "Classes and Objects" in the Pickaxe book for a much more thorough explanation. I took your example above and modified it slightly to show you one possible way to make it work: class Test class << self def say_hello_accessor say_hello end private def say_hello p ''Hello'' end end def say self.class.say_hello_accessor end end Test.new.say Hope this helps. Aaron --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Thanks Aaron! It works.But I feel this way put some additional complexity into Test class. if there have any way can define a private class method and invoke it directly, that would be nice! you said:''You can''t access the private class method from an object instance,because they are in different classes''.you mean every instance have an own class and each of them are different,that''s the reason I can not invoke private class method in instance method,am i right? On Jan 19, 3:52 am, Aaron <baldw...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> > --------------------------- > > class Test > > > def say > > Test::say_hello > > end > > > def self.say_hello > > p ''Hello'' > > end > > > private_class_method :say_hello > > end > > > Test.new.say > > ---------------------- > > run above code will get follow error message > > Test.rb:4:in `say'': private method `say_hello'' called for Test:Class > > (NoMethodError) > > How should I do can both make class methods are private and can be > > invoked > > You can''t access the private class method from an object instance > because they are in different classes. Every ruby object has what is > called a singleton class that contains per-object attributes. See > Chapter 24 "Classes and Objects" in the Pickaxe book for a much more > thorough explanation. > > I took your example above and modified it slightly to show you one > possible way to make it work: > > class Test > class << self > def say_hello_accessor > say_hello > end > > private > def say_hello > p ''Hello'' > end > end > > def say > self.class.say_hello_accessor > end > end > > Test.new.say > > Hope this helps. > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---