From: Eli Bendersky <eliben@...>
Date: 2006-05-19T19:47:54+09:00
Subject: Re: "Declaring" private instance variables


> The behaviors provided by attr_* are implemented using instance
> variables, but that's not the whole instance variable story.  I'm not
> quite sure which constructs you're specifically thinking of, but if
> you want your attr_* methods private, just do:
> 
>    class C
>      private
>      attr_accessor :x
> 
>      # etc.
>    end
> 
> The privacy you're gaining here is the privacy of the x and x=
> methods.  That's separate from the fact that @x is "private" (i.e.,
> only visible to the instance whose variable it is).  Even non-private
> attr_*-generated methods use instance variables.  (Usually the point
> is to make the object's state *less* private :-) too.

Interesting - I didn't know that it's possible to have private variables 
by means of attr_* in 'private'. Thanks

> 
>> My aim is to enhance the readability of my class. It won't affect its
>> usage, just its comprehension when I return in the future trying to grok
>> how it works.
> 
> I don't think you'll get much clearer than:
> 
>    @n = 1
> 

Sure, the question is where to put this line. I find that when such 
"declarations" are interspersed in various methods of a 300-line class, 
it makes comprehension more difficult.


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