Carp/test/sumtypes.carp

;; Generic tests on sumtypes.

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

(deftype A (F [(Fn [] Int)]))
(deftype (Nest a) (Nested [a]) (End []))

(def nest (Nest.Nested (Nest.Nested (Nest.Nested 123))))

(defn one-two-three [] 123)

(defn m [a]
  (match a
    (A.F f) (f)))

(deftest test
  (assert-equal test
    123
    (m (A.F one-two-three))
    "match adds lhs bindings to inner environments")
  (assert-equal test
    "matched!"
    (match nest
          (Nest.Nested (Nest.End))
          "wrong!"
          (Nest.Nested (Nest.Nested (Nest.End)))
          "Also wrong!"
          (Nest.Nested (Nest.Nested (Nest.Nested _)))
          "matched!")
    "Match matches nested sumtype constructors with underscores")
  (assert-equal test
    123
    (match nest
          (Nest.Nested (Nest.Nested (Nest.Nested x)))
          x)
    "Match matches nested sumtype constructors with variables")
  (let [m (Maybe.Just @"hello")]
    (assert-equal test
                  "hello"
                  (match-ref &m
                             (Maybe.Nothing) "wrong"
                             (Maybe.Just x ) x)
                  "match-ref works on simple sumtype"))
  (let [n (Nest.Nested (Nest.Nested (Nest.Nested @"found")))]
    (assert-equal test
                  "found"
                  (match-ref &n
                             (Nest.Nested (Nest.Nested (Nest.Nested s))) s)
                  "match-ref works on deeply nested sumtype"))
)