From: Brian Candler <B.Candler@...>
Date: 2003-06-01T15:57:23+09:00
Subject: Re: [RCR] attr_reader :foo?

On Sun, Jun 01, 2003 at 08:04:16AM +0900, Joel VanderWerf wrote:
> Consider the following code:
> 
>   class C
>     attr_accessor :foo?
>     def initialize
>       @foo = true
>     end
>   end
> 
>   c = C.new
>   p c.foo?               # ==> false
>   c.send("foo?=", true)
>   p c.foo?               # ==> true
>   p c.instance_variables # ["@foo"]
> 
> You can call the reader. You have to bend over backwards to call the 
> writer. You cannot access the attribute itself from within method 
> definitions. You can't even see that it exists using #instance_variables.

instance_variables works for me: I get
["@foo?", "@foo"]

(version 1.6.8, FreeBSD)

But I agree such an instance variable is not directly accessible (e.g.
@foo?.inspect fails with a parse error)

I guess the ? is being treated as part of the ? : operator rather than the
variable name:

     @foo?.1:.2   # return .1 if @foo is true or .2 if @foo is false

Regards,

Brian.