Meta-call predicates: forall/2, maplist/2, maplist/3, include/3, exclude/3

Adds pl-apply-goal helper for safe call/N goal construction (atom or compound),
five solver helpers (pl-solve-forall!, pl-solve-maplist2!, pl-solve-maplist3!,
pl-solve-include!, pl-solve-exclude!), five cond clauses in pl-solve!, and a
new test suite (15/15 passing). Total conformance: 390/390.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/prolog/tests/meta_call.sx

@@ -0,0 +1,197 @@
+;; lib/prolog/tests/meta_call.sx — forall/2, maplist/2, maplist/3, include/3, exclude/3
+(define pl-mc-test-count 0)
+(define pl-mc-test-pass 0)
+(define pl-mc-test-fail 0)
+(define pl-mc-test-failures (list))
+
+(define
+  pl-mc-test!
+  (fn
+    (name got expected)
+    (begin
+      (set! pl-mc-test-count (+ pl-mc-test-count 1))
+      (if
+        (= got expected)
+        (set! pl-mc-test-pass (+ pl-mc-test-pass 1))
+        (begin
+          (set! pl-mc-test-fail (+ pl-mc-test-fail 1))
+          (append!
+            pl-mc-test-failures
+            (str name "\n    expected: " expected "\n    got:      " got)))))))
+
+(define
+  pl-mc-goal
+  (fn
+    (src env)
+    (pl-instantiate (nth (first (pl-parse (str "g :- " src "."))) 2) env)))
+
+(define
+  pl-mc-term-to-sx
+  (fn
+    (t)
+    (cond
+      ((pl-num? t) (pl-num-val t))
+      ((pl-atom? t) (pl-atom-name t))
+      (else t))))
+
+(define
+  pl-mc-list-sx
+  (fn
+    (t)
+    (let
+      ((w (pl-walk-deep t)))
+      (cond
+        ((and (pl-atom? w) (= (pl-atom-name w) "[]")) (list))
+        ((and (pl-compound? w) (= (pl-fun w) "."))
+          (cons
+            (pl-mc-term-to-sx (first (pl-args w)))
+            (pl-mc-list-sx (nth (pl-args w) 1))))
+        (else (list :not-list))))))
+
+(define pl-mc-db (pl-mk-db))
+
+(pl-db-load!
+  pl-mc-db
+  (pl-parse "member(X, [X|_]). member(X, [_|T]) :- member(X, T)."))
+
+(pl-db-load! pl-mc-db (pl-parse "double(X, Y) :- Y is X * 2."))
+
+(pl-db-load! pl-mc-db (pl-parse "even(X) :- 0 is X mod 2."))
+
+;; -- forall/2 --
+
+(pl-mc-test!
+  "forall(member(X,[2,4,6]), 0 is X mod 2) — all even"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "forall(member(X,[2,4,6]), 0 is X mod 2)" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mc-test!
+  "forall(member(X,[2,3,6]), 0 is X mod 2) — 3 is odd, fails"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "forall(member(X,[2,3,6]), 0 is X mod 2)" {})
+    (pl-mk-trail))
+  false)
+
+(pl-mc-test!
+  "forall(member(_,[]), true) — vacuously true"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "forall(member(_,[]), true)" {})
+    (pl-mk-trail))
+  true)
+
+;; -- maplist/2 --
+
+(pl-mc-test!
+  "maplist(atom, [a,b,c]) — all atoms"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "maplist(atom, [a,b,c])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mc-test!
+  "maplist(atom, [a,1,c]) — 1 is not atom, fails"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "maplist(atom, [a,1,c])" {})
+    (pl-mk-trail))
+  false)
+
+(pl-mc-test!
+  "maplist(atom, []) — vacuously true"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "maplist(atom, [])" {})
+    (pl-mk-trail))
+  true)
+
+;; -- maplist/3 --
+
+(pl-mc-test!
+  "maplist(double, [1,2,3], [2,4,6]) — deterministic check"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "maplist(double, [1,2,3], [2,4,6])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mc-test!
+  "maplist(double, [1,2,3], [2,4,7]) — wrong result fails"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "maplist(double, [1,2,3], [2,4,7])" {})
+    (pl-mk-trail))
+  false)
+
+(define pl-mc-env-ml3 {:L (pl-mk-rt-var "L")})
+(pl-solve-once!
+  pl-mc-db
+  (pl-mc-goal "maplist(double, [1,2,3], L)" pl-mc-env-ml3)
+  (pl-mk-trail))
+(pl-mc-test!
+  "maplist(double, [1,2,3], L) — L bound to [2,4,6]"
+  (pl-mc-list-sx (dict-get pl-mc-env-ml3 "L"))
+  (list 2 4 6))
+
+;; -- include/3 --
+
+(pl-mc-test!
+  "include(even, [1,2,3,4,5,6], [2,4,6])"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "include(even, [1,2,3,4,5,6], [2,4,6])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mc-test!
+  "include(even, [], [])"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "include(even, [], [])" {})
+    (pl-mk-trail))
+  true)
+
+(define pl-mc-env-inc {:R (pl-mk-rt-var "R")})
+(pl-solve-once!
+  pl-mc-db
+  (pl-mc-goal "include(even, [1,2,3,4,5,6], R)" pl-mc-env-inc)
+  (pl-mk-trail))
+(pl-mc-test!
+  "include(even, [1,2,3,4,5,6], R) — R bound to [2,4,6]"
+  (pl-mc-list-sx (dict-get pl-mc-env-inc "R"))
+  (list 2 4 6))
+
+;; -- exclude/3 --
+
+(pl-mc-test!
+  "exclude(even, [1,2,3,4,5,6], [1,3,5])"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "exclude(even, [1,2,3,4,5,6], [1,3,5])" {})
+    (pl-mk-trail))
+  true)
+
+(pl-mc-test!
+  "exclude(even, [], [])"
+  (pl-solve-once!
+    pl-mc-db
+    (pl-mc-goal "exclude(even, [], [])" {})
+    (pl-mk-trail))
+  true)
+
+(define pl-mc-env-exc {:R (pl-mk-rt-var "R")})
+(pl-solve-once!
+  pl-mc-db
+  (pl-mc-goal "exclude(even, [1,2,3,4,5,6], R)" pl-mc-env-exc)
+  (pl-mk-trail))
+(pl-mc-test!
+  "exclude(even, [1,2,3,4,5,6], R) — R bound to [1,3,5]"
+  (pl-mc-list-sx (dict-get pl-mc-env-exc "R"))
+  (list 1 3 5))
+
+(define pl-meta-call-tests-run! (fn () {:failed pl-mc-test-fail :passed pl-mc-test-pass :total pl-mc-test-count :failures pl-mc-test-failures}))