From: Austin Ziegler <austin@...>
Date: 2003-09-11T05:57:13+09:00
Subject: Re: What *are* variables? Which are nil now?

> raise "@b1 is nil" if @b1.nil
> @b1.each { |bf|

You mean @b1.nil? -- right?

irb(main):004:0> class B
irb(main):005:1>   def foo
irb(main):006:2>     @b1 = []
irb(main):007:2>     raise "@b1 is nil" if @b1.nil?
irb(main):008:2>     @b1 = nil
irb(main):009:2>     raise "@b1 is nil" if @b1.nil?
irb(main):010:2>     @b1.each { |e| print "." }
irb(main):011:2>   end
irb(main):012:1> end
=> nil
irb(main):013:0> B.new.foo
RuntimeError: @b1 is nil
        from (irb):9:in `foo'
        from (irb):13
irb(main):014:0>

Is there a chance that @b1 is becoming nil between your test and the each 
because the program is threaded?

As far as I know, there's no way to know what variables (labels) are 
referring to what values (objects).

-austin
--
austin ziegler    * austin@halostatue.ca * Toronto, ON, Canada
software designer * pragmatic programmer * 2003.09.10
                                         * 16.50.48