From: Eric Armstrong <Eric.Armstrong@...>
Date: 2006-07-14T09:40:38+09:00
Subject: Re: Initialize a variable in an extended class

dblack@wobblini.net wrote:
> On Fri, 14 Jul 2006, Eric Armstrong wrote:
> 
>>    Note: For a long time it wasn't clear to me that
>>    it is impossible to initialize an instance variable
>>    outside of a method. Coming from the Java world, I
>>    just assumed that this would be legal:
>>      class Foo
>>        @bar = 2
>>      end
>>
>>    But it isn't. (A fact that needs to be spelled out
>>    somewhere, for Java types.)
> 
> I'm not sure what you mean by "somewhere".  It gets talked about and
> explained regularly here, as well as in various books, wikis, etc.
> The workings of instance variables are not a closely guarded secret
> :-)
>
Thanks for the smiley. I haven't been spending enough time 
here, it seems.
:_)

> When you see this:
> 
>   @var
> 
> you are seeing an instance variable belonging to whatever object is,
> at that point, playing the role of "self" (the default object).
> 
> At the top level of a class definition block, "self" is the class
> object (Foo in your example).
> 
> So in your example, you've got an instance variable belonging to the
> class object Foo.  There's no connection at all between this instance
> variable and any instance variable that may come into being later when
> some other object is "self" (including an instance of Foo).
> 
Getting clearer all the time.
thanks.

Now for the bigger problem... how to reuse data when
I'm extending an existing class...