Carp/examples/lifetimes.carp

(Debug.sanitize-addresses)
(Project.config "print-ast" true)

;; Preventing the usage of a reference to a deleted object
;; (defn f []
;;   (let-do [x @"DATA"
;;            r &x]
;;     (delete x)
;;     (IO.println r)))

;; Same as above, but deleting the argument
;; (defn g [x]
;;   (let-do [r &x]
;;     (delete (the String x))
;;     (IO.println r)))

;; A function accepting two refs and returning one of them
;; (defn two-refs [x a b]
;;   (if x
;;     (the (Ref t q) a)
;;     (the (Ref t w) b)))

;; Lambdas
;; (defn l []
;;   (let [x @"DATA"
;;         r &x
;;         f (fn [] (IO.println r))]
;;     (do
;;       (String.delete x)
;;       (f))))

;; (defn from-ptr [a]
;;   (if (null? a)
;;     (Maybe.Nothing)
;;     (Maybe.Just @(Pointer.to-ref a))))

;; (defn pair-eq [p1 p2]
;;   (and (= (Pair.a p1) (Pair.a p2))
;;        (= (Pair.b p1) (Pair.b p2)))
;;   )

;; (defn map-put []
;;   (fn [b]
;;     (let [n &b]
;;       ())))


;; (defn f [x y]
;;   (let [s @"hej"
;;         z 123]
;;     (Int.+ x y)))



;; (defn f []
;;   &100) ;; TODO: Number literals should create prim var deleter too!



;; use-ref-in-lambda-after-free
;; (defn boo []
;;   (let-do [data @"DATA"
;;            r &data
;;            f (fn []
;;                (IO.println (id r)))]
;;     ;;(String.delete data)
;;     (f)))



;; (defn foo []
;;   (let-do [data [10 20 30]
;;            r &data
;;            f (fn [] (Array.nth r 1))]
;;     ;;(Array.delete data)
;;     (println* (f))))

;; (defn lam []
;;   (let [stuff [100 200 300]
;;         ;;r &stuff
;;         f (fn []
;;             (println* (id &stuff)))]
;;     (f)))



;; Problematic order of arguments, the variable 'b' will depend on 'snake', which is consumed first in the call to Snake.set-body
;; (use Array)
;; (deftype Snake [body (Array Int)])

;; (defn grow [snake]
;;   (let [b (Snake.body &snake)]
;;     (Snake.set-body snake (push-back @b 0))))

;;(unsafe-last b)


;; (defn dangling-1 []
;;   (let [b [1 2 3]]
;;     &b))

;; (defn dangling-2 []
;;   (let [b [1 2 3]
;;         r &b]
;;     r))


;; (defn unique []
;;   (let [r1 (the &String "DATA")
;;         r2 (the &String "DATA") ;; should get another lifetime variable than r1
;;         r3 "DATA"]
;;     ()))


;; (defn fool [s1 s2]
;;   (let [r1 (the (Ref String Static) s1)
;;         r2 (the (Ref String b) s2)]
;;     (do
;;       (if (= r1 r2) () ())
;;       ;;(delete s1)
;;       ;;(= r1 r2)
;;       ;;()
;;       r2)))


;; This should be detected as an error too:
;; (defn f [s]
;;   (let [r &s]
;;     r))
;;(f @"hej")



;; (defn magic []
;;   (let [s @"DATA"]
;;     &s)) ;; shouldn't work either

;; (defn simple-fool []
;;   (let [r (magic) ;; 'magic' returns (Ref String a)
;;         static (the (Ref String Static) "")]
;;     (do
;;       (if (= r static) () ()) ;; shouldn't just be possible to trick 'r' that its lifetime is Static
;;       ())))

;; (defn first [xs]
;;   (Array.nth xs 0))

;;(defn f [x] (fn [] (IO.println x)))



;; (defn g []
;;   (let-do [s @"DATA"
;;            r &s
;;            f (fn [] (IO.println r))]
;;     ;;(delete s)
;;     ;;(f)
;;     f))



;; (defn ok [r]
;;   (let-do [f (fn [] (IO.println r))]
;;     f))



(deftype Blah [x Int])

(defn trick []
  (let[s1 (Blah.init 100)
       r1 &s1
       g (let [s2 (Blah.init 200)
               r2 &s2
               f (fn [] (println* r1 r2))]
           f)]
    (g) ;; shouldn't work because 's2' has been deleted and 'r2' is thus a dead reference
    ))