From: Joel VanderWerf <vjoel@...>
Date: 2001-12-16T04:22:11+09:00
Subject: [ruby-talk:28639] Re: assigning to class variable works in string,  not in block

ts wrote:
> 
> >>>>> "J" == Joel VanderWerf <vjoel@PATH.Berkeley.EDU> writes:
> 
>  Write it like this
> 
> J> module M
> J>   def self.append_features base_class
> J>       base_class.class_eval {@@base_class = self} # fails
> J> #      base_class.class_eval "@@base_class = self" # ok
> J>   end
> J> end
> 
>    module M
>       class << self
>          def append_features base_class
>             base_class.class_eval {@@base_class = self}
>          end
>       end
>    end

Thanks, Guy, that works.

Was the problem that @@base_class was not getting bound to the class
variable of BaseClass, because it was referenced in a block whose scope
was module M? But then why did the error message refer to BaseClass, and
not M: "uninitialized class variable @@base_class in BaseClass
(NameError)"?

--
Joel VanderWerf                          California PATH, UC Berkeley
mailto:vjoel@path.berkeley.edu                     Ph. (510) 231-9446
http://www.path.berkeley.edu                       FAX (510) 231-9512