prolog: reverse.pl + reverse.sx (naive via append), 6 tests

lib/prolog/tests/programs/reverse.pl

@@ -0,0 +1,7 @@
+%% reverse/2 — naive reverse via append/3.
+%% Quadratic — accumulates the reversed prefix one append per cons.
+reverse([], []).
+reverse([H|T], R) :- reverse(T, RT), append(RT, [H], R).
+
+append([], L, L).
+append([H|T], L, [H|R]) :- append(T, L, R).

lib/prolog/tests/programs/reverse.sx

@@ -0,0 +1,113 @@
+;; lib/prolog/tests/programs/reverse.sx — naive reverse/2 via append/3.
+;;
+;; Mirrors reverse.pl (embedded as a string here).
+
+(define pl-rv-test-count 0)
+(define pl-rv-test-pass 0)
+(define pl-rv-test-fail 0)
+(define pl-rv-test-failures (list))
+
+(define
+  pl-rv-test!
+  (fn
+    (name got expected)
+    (begin
+      (set! pl-rv-test-count (+ pl-rv-test-count 1))
+      (if
+        (= got expected)
+        (set! pl-rv-test-pass (+ pl-rv-test-pass 1))
+        (begin
+          (set! pl-rv-test-fail (+ pl-rv-test-fail 1))
+          (append!
+            pl-rv-test-failures
+            (str name "\n    expected: " expected "\n    got:      " got)))))))
+
+(define
+  pl-rv-term-to-sx
+  (fn
+    (t)
+    (cond
+      ((pl-num? t) (pl-num-val t))
+      ((pl-atom? t) (pl-atom-name t))
+      (true (list :complex)))))
+
+(define
+  pl-rv-list-walked
+  (fn
+    (w)
+    (cond
+      ((and (pl-atom? w) (= (pl-atom-name w) "[]")) (list))
+      ((and (pl-compound? w) (= (pl-fun w) ".") (= (len (pl-args w)) 2))
+        (cons
+          (pl-rv-term-to-sx (first (pl-args w)))
+          (pl-rv-list-walked (nth (pl-args w) 1))))
+      (true (list :not-list)))))
+
+(define pl-rv-list-to-sx (fn (t) (pl-rv-list-walked (pl-walk-deep t))))
+
+(define
+  pl-rv-goal
+  (fn
+    (src env)
+    (pl-instantiate (nth (first (pl-parse (str "g :- " src "."))) 2) env)))
+
+(define
+  pl-rv-prog-src
+  "reverse([], []). reverse([H|T], R) :- reverse(T, RT), append(RT, [H], R). append([], L, L). append([H|T], L, [H|R]) :- append(T, L, R).")
+
+(define pl-rv-db (pl-mk-db))
+(pl-db-load! pl-rv-db (pl-parse pl-rv-prog-src))
+
+(define pl-rv-env-1 {})
+(define pl-rv-goal-1 (pl-rv-goal "reverse([], X)" pl-rv-env-1))
+(pl-solve-once! pl-rv-db pl-rv-goal-1 (pl-mk-trail))
+
+(pl-rv-test!
+  "reverse([], X) → X = []"
+  (pl-rv-list-to-sx (dict-get pl-rv-env-1 "X"))
+  (list))
+
+(define pl-rv-env-2 {})
+(define pl-rv-goal-2 (pl-rv-goal "reverse([1], X)" pl-rv-env-2))
+(pl-solve-once! pl-rv-db pl-rv-goal-2 (pl-mk-trail))
+
+(pl-rv-test!
+  "reverse([1], X) → X = [1]"
+  (pl-rv-list-to-sx (dict-get pl-rv-env-2 "X"))
+  (list 1))
+
+(define pl-rv-env-3 {})
+(define pl-rv-goal-3 (pl-rv-goal "reverse([1, 2, 3], X)" pl-rv-env-3))
+(pl-solve-once! pl-rv-db pl-rv-goal-3 (pl-mk-trail))
+
+(pl-rv-test!
+  "reverse([1, 2, 3], X) → X = [3, 2, 1]"
+  (pl-rv-list-to-sx (dict-get pl-rv-env-3 "X"))
+  (list 3 2 1))
+
+(define pl-rv-env-4 {})
+(define pl-rv-goal-4 (pl-rv-goal "reverse([a, b, c, d], X)" pl-rv-env-4))
+(pl-solve-once! pl-rv-db pl-rv-goal-4 (pl-mk-trail))
+
+(pl-rv-test!
+  "reverse([a, b, c, d], X) → X = [d, c, b, a]"
+  (pl-rv-list-to-sx (dict-get pl-rv-env-4 "X"))
+  (list "d" "c" "b" "a"))
+
+(pl-rv-test!
+  "reverse([1, 2, 3], [3, 2, 1]) succeeds"
+  (pl-solve-once!
+    pl-rv-db
+    (pl-rv-goal "reverse([1, 2, 3], [3, 2, 1])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-rv-test!
+  "reverse([1, 2], [1, 2]) fails"
+  (pl-solve-once!
+    pl-rv-db
+    (pl-rv-goal "reverse([1, 2], [1, 2])" {})
+    (pl-mk-trail))
+  false)
+
+(define pl-reverse-tests-run! (fn () {:failed pl-rv-test-fail :passed pl-rv-test-pass :total pl-rv-test-count :failures pl-rv-test-failures}))