Carp/test/dynamic-closures.carp

(load "Test.carp")
(use Test)

(defdynamic x 400)
(defdynamic z 0)

;; close over a global variable
(defdynamic closure-one
  (fn [] x))

;; close over an argument
(defdynamic closure-two
  (fn [x] x))

;; close over a let binding
(defdynamic closure-three
  (fn [] (let [x 4] x)))

;; dynamics can close over a global variable before it is defined
(defdynamic closure-four
  (fn [] y))

;; nested closures prefer closed-over internal environments
(defdynamic closure-five
  (fn [] (let [x 5] (fn [] x))))

;; closures can update the global environment (issue #1181)
(defdynamic closure-six
  (fn [] (set! z (inc z))))

(defdynamic y 500)

(defmacro test-closure-one [] (closure-one))
(defmacro test-closure-two [] (closure-two 3))
(defmacro test-closure-three [] (closure-three))
(defmacro test-closure-four [] (closure-four))
(defmacro test-closure-five [] ((closure-five)))
(defmacro test-closure-six []
  (do (closure-six)
      (closure-six)
      (closure-six)
      z))

;; Change the global value of x (closed over in closure-one)
(set! x 1000)

(deftest test
  (assert-equal test
    1000
    (test-closure-one)
    "closures over global variables get the global variable's latest state.")
  (assert-equal test
    3
    (test-closure-two)
    "closures with arguments use argument values")
  (assert-equal test
    4
    (test-closure-three)
    "closures with let bindings prefer let bindings over global names")
  (assert-equal test
    500
    (test-closure-four)
    "dynamic closures can refer to global bindings delcared after the closure")
  (assert-equal test
    5
    (test-closure-five)
    "nested closures prefer closed-over bindings")
  (assert-equal test
    3
    (test-closure-six)
    "closures can update the global environment")
)