From: James Byrne <byrnejb@...>
Date: 2006-02-25T04:51:16+09:00
Subject: Re: Private methods - only available to oneself?

Hal Fulton wrote:
> Minkoo Seo wrote:
>> Thanks, Erik. I'm afraid that I'm not a native English spearker, so
>> sometimes it's not easy to express my own idea in exact English
>> expression.
>> 
>> Of course, I did look up the reference and found what instance_eval
>> does when being called. What I tried to ask was, as you stated,
>> "If we can do this, what's the purpose of 'protected' or 'private'?"
> 
> 'private' is not like a locked door. It is like a sign saying "Do Not
> Enter.'
> 
> Or look at it this way: It makes it "more difficult" to access private
> vars (so that you will know you shouldn't), but doesn't make it
> impossible (in case you really, really need to).
> 
> 
> Hal

I do not understand why within the class definiton the Ruby interpreter 
distinguishes between implicit and explict calls to self.

i.e

Class Foo

def foo_one
  bar
end

def foo_two
  self.bar
end

def bar
  puts "In Bar"
end

private  :bar

end

f = Foo.new

f.foo_one
-> "In Bar"

f.foo_two
-> NoMethodError: private method `bar' called for

This leads to the inference that self !=== <implicit self> which strikes 
me as decidedly odd.  Self is either always self or it is not and if not 
then what is it? Whether self is declared as the the receiver or left 
for the interpreter to contextually establish should make no difference 
to the effect of a private method.  Is this difference due to a parsing 
limitation or a purposeful design decision that serves some intent I 
cannot presently fathom?  If the latter, then what is the purpose served 
by this disticntion between an explicit and implicit self receiver?

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