On Jan 15, 2008, at 3:43 PM, David A. Black wrote:

>
> I guess it would have that effect, but I've seen lots of instance
> variable initialization in classes that might be subclassed, and I
> don't remember ever seeing a conditional one.
>

there is one in that very file ;-)

  431 # SortedSet implements a set which elements are sorted in  
order.  See Set.
  432 class SortedSet < Set
  433   @@setup = false
  434
  435   class << self
  436     def [](*ary)        # :nodoc:
  437       new(ary)
  438     end
  439
  440     def setup   # :nodoc:
  441       @@setup and return
  442
  443       module_eval {
  444         # a hack to shut up warning
  445         alias old_init initialize
  446         remove_method :old_init
  447       }
  448       begin
  449         require 'rbtree'
  450
  451         module_eval %{
  452           def initialize(*args, &block)
  453             @hash = RBTree.new
  454             super
  455           end
  456         }

and still no RBTree in the stdlib ;-(


a @ http://codeforpeople.com/
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h.h. the 14th dalai lama