initialize

[Jonathan Leighton]

Should initialize() be public, private or protected, and why?

Thanks

 

[ts]

J> Should initialize() be public, private or protected, and why?

moulon% cat b.rb
#!/usr/bin/ruby
class A
protected
def initialize
end
end

p A.private_instance_methods(false)
p A.protected_instance_methods(false)
moulon%

moulon% ./b.rb
["initialize"]
[]
moulon%



Guy Decoux

 

[Jonathan Leighton]

J> Should initialize() be public, private or protected, and why?

moulon% cat b.rb
#!/usr/bin/ruby
class A
protected
def initialize
end
end

p A.private_instance_methods(false)
p A.protected_instance_methods(false)
moulon%

moulon% ./b.rb
["initialize"]
[]
moulon%

Thanks for the reply. Forgive me, but I don't understand what the point
is in your example? Or why initialize is returned by
private_instance_methods() but not protected_instance_methods()? Could
you elaborate a bit please?

Thanks

 

[ts]

J> Thanks for the reply. Forgive me, but I don't understand what the point
J> is in your example? Or why initialize is returned by
J> private_instance_methods() but not protected_instance_methods()? Could
J> you elaborate a bit please?

#initialize (like #initialize_copy) is *always* a private method. Even if
you try to define it as public or protected, ruby will make it a private
method.


Guy Decoux

 

[ts]

t> #initialize (like #initialize_copy) is *always* a private method. Even if
t> you try to define it as public or protected, ruby will make it a private
t> method.

Well, there is an exception when you redefine its state after the creation

moulon% cat b.rb
#!/usr/bin/ruby
class A
def initialize
end
protected :initialize
end

A.new
moulon%

moulon% ./b.rb
/b.rb:8:in `new': protected method `initialize' called for #<A:0xb7d64e94> (NoMethodError)
from ./b.rb:8
moulon%

Guy Decoux

 

[Jonathan Leighton]

J> Thanks for the reply. Forgive me, but I don't understand what the point
J> is in your example? Or why initialize is returned by
J> private_instance_methods() but not protected_instance_methods()? Could
J> you elaborate a bit please?

#initialize (like #initialize_copy) is *always* a private method. Even if
you try to define it as public or protected, ruby will make it a private
method.

Ah, okay, thanks.