From: Joel VanderWerf <vjoel@...>
Date: 2005-07-26T02:53:31+09:00
Subject: Re: An array updatable?

EdUarDo wrote:
> Hi again,
> 
> I have this class:
> 
> class A
>     attr_reader :name, :cars
>     attr_writer :name
> 
>     def initialize(name)
>         @name = name
>         @cars = Array.new()
>     end
> end
> 
> a = A.new("xxxx")
> a.cars << "vectra" << "megane"
> puts a
> 
> output:
> 
> vectra
> megane
> 
> Why can I access cars and modify it if I have not declared it how
> attr_writer. Must I simply declare it private?

a.cars = nil # This gives an error

The restriction is on the variable, not on the object that is bound to
the variable. To restrict that object, you can #freeze it, but that will
affect all access, including within the class A.