prolog: member.pl + member.sx generator, 7 tests

lib/prolog/tests/programs/member.pl

@@ -0,0 +1,4 @@
+%% member/2 — list membership.
+%% Generates all solutions on backtracking when the element is unbound.
+member(X, [X|_]).
+member(X, [_|T]) :- member(X, T).

lib/prolog/tests/programs/member.sx

@@ -0,0 +1,91 @@
+;; lib/prolog/tests/programs/member.sx — member/2 generator.
+
+(define pl-mb-test-count 0)
+(define pl-mb-test-pass 0)
+(define pl-mb-test-fail 0)
+(define pl-mb-test-failures (list))
+
+(define
+  pl-mb-test!
+  (fn
+    (name got expected)
+    (begin
+      (set! pl-mb-test-count (+ pl-mb-test-count 1))
+      (if
+        (= got expected)
+        (set! pl-mb-test-pass (+ pl-mb-test-pass 1))
+        (begin
+          (set! pl-mb-test-fail (+ pl-mb-test-fail 1))
+          (append!
+            pl-mb-test-failures
+            (str name "\n    expected: " expected "\n    got:      " got)))))))
+
+(define
+  pl-mb-goal
+  (fn
+    (src env)
+    (pl-instantiate (nth (first (pl-parse (str "g :- " src "."))) 2) env)))
+
+(define pl-mb-prog-src "member(X, [X|_]). member(X, [_|T]) :- member(X, T).")
+
+(define pl-mb-db (pl-mk-db))
+(pl-db-load! pl-mb-db (pl-parse pl-mb-prog-src))
+
+(pl-mb-test!
+  "member(2, [1, 2, 3]) succeeds"
+  (pl-solve-once!
+    pl-mb-db
+    (pl-mb-goal "member(2, [1, 2, 3])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mb-test!
+  "member(4, [1, 2, 3]) fails"
+  (pl-solve-once!
+    pl-mb-db
+    (pl-mb-goal "member(4, [1, 2, 3])" {})
+    (pl-mk-trail))
+  false)
+
+(pl-mb-test!
+  "member(X, []) fails"
+  (pl-solve-once!
+    pl-mb-db
+    (pl-mb-goal "member(X, [])" {})
+    (pl-mk-trail))
+  false)
+
+(pl-mb-test!
+  "member(X, [a, b, c]) generates 3 solutions"
+  (pl-solve-count!
+    pl-mb-db
+    (pl-mb-goal "member(X, [a, b, c])" {})
+    (pl-mk-trail))
+  3)
+
+(define pl-mb-env-1 {})
+(define pl-mb-goal-1 (pl-mb-goal "member(X, [11, 22, 33])" pl-mb-env-1))
+(pl-solve-once! pl-mb-db pl-mb-goal-1 (pl-mk-trail))
+
+(pl-mb-test!
+  "member(X, [11, 22, 33]) first solution X = 11"
+  (pl-num-val (pl-walk-deep (dict-get pl-mb-env-1 "X")))
+  11)
+
+(pl-mb-test!
+  "member(2, [1, 2, 3, 2, 1]) matches twice on backtrack"
+  (pl-solve-count!
+    pl-mb-db
+    (pl-mb-goal "member(2, [1, 2, 3, 2, 1])" {})
+    (pl-mk-trail))
+  2)
+
+(pl-mb-test!
+  "member with unbound list cell unifies"
+  (pl-solve-once!
+    pl-mb-db
+    (pl-mb-goal "member(a, [X, b, c])" {})
+    (pl-mk-trail))
+  true)
+
+(define pl-member-tests-run! (fn () {:failed pl-mb-test-fail :passed pl-mb-test-pass :total pl-mb-test-count :failures pl-mb-test-failures}))