From: Simon Strandgaard <neoneye@...>
Date: 2003-11-21T19:12:20+09:00
Subject: continuations and clone problem

This class should convert internal-iterators to external-iterators.
But how do I clone them?

Any advice are deeply appreciated.

--
Simon Strandgaard




server> ruby a.rb
a.rb:28:in `next': undefined method `call' for false:FalseClass (NoMethodError)
        from a.rb:28:in `callcc'
        from a.rb:28:in `next'
        from a.rb:43
server> expand -t2 a.rb 
class Object
  def deep_clone
    Marshal::load(Marshal.dump(self))
  end
end

class IteratorContinuation
  def initialize(instance, symbol)
    @instance = instance
    @symbol = symbol
    first
  end
  def first
    @value = nil
    @resume_where = false
    @return_where = Proc.new{}
    @instance.method(@symbol).call {|i|
      @value = i
      callcc{|@resume_where|
        @return_where.call
        return
      }
    }
    @resume_where = false
    @return_where.call
  end
  def next
    callcc{|@return_where| @resume_where.call }
  end
  def is_done?
    @resume_where == false
  end
  def current 
    @value
  end
end

i1 = IteratorContinuation.new("hello world", :each_byte)
i1.next
i1.next
i1.next
i2 = i1.clone   # deep_clone not possible
i2.next
p i1.current
p i2.current
server>