From: Dave Thomas <Dave@...>
Date: 2001-03-06T06:11:53+09:00
Subject: [ruby-talk:12060] Re: RCR: shortcut for instance variable initialization

"Christoph Rippel" <crippel@primenet.com> writes:

> class Whatever
> 
> def will_be_rounded=(number)
> 	raise 'Not a number' unless kind_of? Numeric
> 	@will_be_number = number.round
> end
> 
> def initialize(will_be_rounded@)
> 	...
> end
> attr_accessor :will_be_rounded
> end
> 
> does a call to initialize invoke ``@will_be_rounded=''
> or```will_be_rounded=''? 

There is no such method as '@will_be_rounded='.  The attr_accessor
call will overwrite the method you defined with it's own:

  class Dave
    def val=(n)
      puts "in my val"
      @val = 123
    end
    attr_accessor :val
  end

  d = Dave.new
  d.val = 432
  p d.val     #=> 432


> Ps. I sometimes wonder if Ruby could have done without
> variables at all (I believe this) and only use attributes 
> but this is a different matter.

Attributes are simply accessor functions to instance variables.


Dave