From: zdennis <zdennis@...>
Date: 2006-04-08T01:56:45+09:00
Subject: Re: Simple Question About Deleting Instances

Nathan Olberding wrote:
> zdennis wrote:
>>> def method_name()
>>> ...
>>> end
>> This is an instance method. It works on the instance of Report.
>>
>>> And my variables are all defined as:
>>>
>>> @@var = ...
>> This is a class variable. All Reports will share this variable. You 
>> probably want to make it an instance variable with one @ symbols.
>>
>> @var = ...
> 
> I replaced all instances of "@@" with "@" in my script since I don't 
> need any class variables. Now, Ruby generates errors telling me that all 
> of these variables are unknown when referenced from instance methods.

Can you post code along with your questions ? It makes it so much easier
to help.

> 
> Do I need to make any special kinds of accessors or anything?
> 
> And on that note, how do I do something like attr_reader :@@var? Ruby 
> doesn't seem to know what to do when I put those @s there.

When using attr_reader, attr_writer, attr_accessor you dont need to
include the @ symbols.

class A
  attr_accessor :var # this will create an instance variable @var
                     # plus the get/set methods for var on an instance
                     # of A

  class << self
     attr_accessor :foo # this will create a class method var for you
                        # plus the get/set methods for var on the class
                        # A. The var will be created as an instance
                        #variable @var on the class A
  end
end

a  = A.new
a.var = 5
puts a.var #outputs 5

b = A.new
b.var = 10
puts  b.var #outputs 10

A.foo = 100
puts A.foo  #outputs 100

Please do read the Chris Pines Learn To Program from my last post. It
seems you are guessing at what goes where and you need little a
guidance, Chris Pines Learn to Program will help you get started in the
right direction.

Zach