From: Ian Macdonald <ian@...>
Date: 2002-05-23T08:43:09+09:00
Subject: confused about access control

Hi,

I'm rather confused about access control. Observe this:

irb(main):001:0> class String
irb(main):002:1>   protected
irb(main):003:1>   def undot!
irb(main):004:2>     sub!(/^\.\./, '.')
irb(main):005:2>   end
irb(main):006:1> end
nil
irb(main):007:0> class Foo
irb(main):008:1>   foo = '..123'
irb(main):009:1>   foo.undot!
irb(main):010:1> end
NameError: protected method `undot!' called for "..123":String
        from (irb):9

Why does this fail?

The pick-axe book says:

"Protected methods can be invoked only by objects of the defining
class and its subclasses."

Well, foo is an instance of String, which is the class that defines
the undot! method, so why does this not work?

I'm clearly missing something obvious.

Ian
-- 
Ian Macdonald               | Fourth Law of Thermodynamics:  If the
ian@caliban.org             | probability of success is not almost one,
                            | it is damn near zero.   -- David Ellis 
                            | 
                            |