delimc

A delimited continuations library for Clojure 1.4.0 (and 1.3.0). Portions based on cl-cont by Slava Akhmechet (http://defmacro.org).

(def cont1 (atom nil))
(def cont2 (atom nil))
(def cont3 (atom nil))
(def cont4 (atom nil))

(reset (+ 1 (apply (fn [a b c]
                     (+ (shift k
                          (reset! cont1 k)
                            (k 1))
                         a b c))
                    3 4 (list 5)))) ;; 14

(@cont1 2) ;; 15

(reset
  (+ 1 (reset (shift k
                (reset! cont2 k)
                (k 2)))
       (reset (shift k
                (reset! cont3 k)
                (k 3))))) ;; 6

(@cont2 4) ;; 8
(@cont3 10) ;; 15

(reset (str "Hello" (shift k
                      (reset! cont4 k)
                        (k ", today is "))
            "a nice day!")) ; "Hello, today is a nice day"

(@cont4 ", yesterday was ") ; "Hello, yesterday was a nice day"

References

• Literate Engines in Lisp
• Threads Yield Continuations
• Yield: Mainstream Delimited Continuations
• Composable Continuations Tutorial
• A Monadic Framework for Subcontinuations
• Subcontinuations
• Models of Control and Their Implicatations for Programming Languages
• Monads and Composable Continuations