>>3
cons cells are passed by reference, always.
>>8
call/cc ...
THE RESULT OF CALL/CC IS THAT YOU CREATE A "RETURN" FUNCTION:
(define (foo return)
(return 1)
(display "fail"))
(call/cc foo) ; the result of call/cc is whatever foo evaluates too, but foo can shortcut the computation and immediatly make (call/cc foo) return a value by calling the function it recieves with the value it wants to return