datalog: comprehensive integration test (184/184)

Single program exercising recursion + stratified negation +
aggregation + comparison composed end-to-end via dl-eval. Confirms
the full pipeline (parser → safety → stratifier → semi-naive +
aggregate post-pass → query) on a non-trivial program.

  edge graph + banned set →
    reach transitive closure →
    safe (reach minus banned) →
    reach_count via count aggregation grouped by source →
    popular = reach_count >= 2

lib/datalog/scoreboard.json

@@ -1,8 +1,8 @@
 {
   "lang": "datalog",
-  "total_passed": 183,
+  "total_passed": 184,
   "total_failed": 0,
-  "total": 183,
+  "total": 184,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":18,"failed":0,"total":18},
@@ -12,8 +12,8 @@
     {"name":"semi_naive","passed":8,"failed":0,"total":8},
     {"name":"negation","passed":10,"failed":0,"total":10},
     {"name":"aggregates","passed":18,"failed":0,"total":18},
-    {"name":"api","passed":13,"failed":0,"total":13},
+    {"name":"api","passed":14,"failed":0,"total":14},
     {"name":"demo","passed":18,"failed":0,"total":18}
   ],
-  "generated": "2026-05-08T09:45:03+00:00"
+  "generated": "2026-05-08T09:47:44+00:00"
 }

lib/datalog/scoreboard.md

@@ -1,6 +1,6 @@
 # datalog scoreboard
 
-**183 / 183 passing** (0 failure(s)).
+**184 / 184 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -12,5 +12,5 @@
 | semi_naive | 8 | 8 | ok |
 | negation | 10 | 10 | ok |
 | aggregates | 18 | 18 | ok |
-| api | 13 | 13 | ok |
+| api | 14 | 14 | ok |
 | demo | 18 | 18 | ok |

lib/datalog/tests/api.sx

@@ -213,6 +213,23 @@
           "?- p(X), q(X).")
         (list {:X 2} {:X 3}))
 
+      ;; Comprehensive integration: recursion + stratified negation
+      ;; + aggregation + comparison composed in a single program.
+      ;; (Uses _Anything as a regular var instead of `_` so the
+      ;;  outer rule binds via the reach lit.)
+      (dl-api-test-set! "integration"
+        (dl-eval
+          (str
+            "edge(a, b). edge(b, c). edge(c, d). edge(a, d). "
+            "banned(c). "
+            "reach(X, Y) :- edge(X, Y). "
+            "reach(X, Z) :- edge(X, Y), reach(Y, Z). "
+            "safe(X, Y) :- reach(X, Y), not(banned(Y)). "
+            "reach_count(X, N) :- reach(X, Z), count(N, Y, safe(X, Y)). "
+            "popular(X) :- reach_count(X, N), >=(N, 2).")
+          "?- popular(X).")
+        (list {:X (quote a)}))
+
       ;; dl-rule-from-list with no arrow → fact-style.
       (dl-api-test-set! "no arrow → fact-like rule"
         (let