Welcome to DrRacket, version 7.4 [3m].
Language: racket, with debugging [custom]; memory limit: 128 MB.
> (define g (make-stream 1 2 (+ 3 4)))
> (next! g)
1
> (next! g)
2
> (next! g)
7
> (next! g)
'DONE
> (shift hi 8)
. . shift: undefined;
 cannot reference an identifier before its definition
> (require racket/control)
> (shift hi 8)
8
> (shift hi (+ 5 9))
14
> hi
. . hi: undefined;
 cannot reference an identifier before its definition
> (+ 5 (shift hi 1))
1
> (define cont (void))
> (+ 5 (shift k (set! cont k)))
> k
. . k: undefined;
 cannot reference an identifier before its definition
> cont
#<procedure:...cket/control.rkt:157:23>
> (cont 7)
12
> (+ 5 (shift k (set! cont k))) ; k = (+ 5 _)
> (cont 7)
12
> (cont 10)
15
> (cont (+ 5 (shift k 10)))
10
> (+ 5 (shift k 1))
1
> (+ 5 (shift k (k 1)))
6
> (+ 5 (shift k
         (* (k 1) (k 2)))) ; k = (+ 5 _)
42
> ; ==> (* (k 1) (k 2)) ==> (* (+ 5 1) (+ 5 2)) ==> (* 6 7) ==> 42
42
42
> (list (+ 5 (shift k
         (append (k 1) (k 2))))) ; k = (list (+ 5 _))
'(6 7)
> ; ==> (append (k 1) (k 2)) ==> (append (list (+ 5 1)) (list (+ 5 2)))
'(6 7)
'(6 7)
> (define a (+ 5 (shift k (* (k 1) (k 2)))))
. . *: contract violation
  expected: number?
  given: #<void>
  argument position: 1st
  other arguments...:
> (define a (+ 5 (shift k (* (k 1) (k 2))))) ; k = (define a (+ 5 _))
. . *: contract violation
  expected: number?
  given: #<void>
  argument position: 1st
  other arguments...:
> (define a (reset (+ 5 (shift k (* (k 1) (k 2))))))
> a
42
> ; k = (+ 5 _)
a
42
> (reset (+ 2 4 5))
11
> (+ (shift k 5) (/ 1 0))
5
> (+ (shift k (k 5)) (/ 1 0))
. . /: division by zero
>