From: Mike Sassak <msassak@...>
Date: 2001-10-05T14:09:53+09:00
Subject: [ruby-talk:22116] Object construction with block and private methods

Hi!

I was reading the "Object Construction and Blocks" article on
www.rubycentral.com a couple of days ago and noticed what looks to me
like some odd behavior when you initialize an object with a block and
instance_eval.

Suppose I've got a class like so:

class Foo
  def initialize(&block)
    instance_eval(&block)
  end
  def method
    puts "Hello, world!"
  end

  def privMethod
    puts "Goodbye, world!"
  end
  private :privMethod
end

and I go to initialize it with a block:

a = Foo.new {
  method
  privMethod
}

When I run the code, even though "privMethod" is marked as private, it
is still callable so long as it is called in the block when the object
is constructed. 

Afterwards, if I run "a.privMethod" I get an error. But not when it's
initializing. I'm guessing that Ruby allows this because instance_eval
changes the value of self to be the context of the object. So while it's
technically not a bug... isn't that still breaking encapsulation?

Thanks,
-mike