From: dblack@...
Date: 2002-10-15T06:51:31+09:00
Subject: Re: Referring to instance vars in a Struct?

Hi --

On Tue, 15 Oct 2002, Chris Morris wrote:

> But the point for me is still the surprise of not having an instance var
> inside a Struct (although it does make sense that this is probably pushing
> Structs beyond their intended use).

One way to look at it: having methods that set and retrieve same-named
instance variables is one way of implementing object attributes, and
while it's convenient (especially with the attr_xxx wrappers for
method creation), it's not the only way.

So Structs are in the attribute business, but how they do it is not
part of the deal.

Of course, if you want to, you can always get under the hood:

  (s = (S = Struct.new :thing) .new) .thing = 123
  # (I was shooting for a palindrome :-)  Anyway....

  class S
    alias :oldthing :thing
    def thing
      puts "Intercepted attribute get"
      oldthing
    end
  end

  p s.thing
              #  => Intercepted attribute get
              #     123

etc.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav