datalog: disjunction via multiple rules test (231/231)

lib/datalog/scoreboard.json

@@ -1,13 +1,13 @@
 {
   "lang": "datalog",
-  "total_passed": 230,
+  "total_passed": 231,
   "total_failed": 0,
-  "total": 230,
+  "total": 231,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":18,"failed":0,"total":18},
     {"name":"unify","passed":28,"failed":0,"total":28},
-    {"name":"eval","passed":31,"failed":0,"total":31},
+    {"name":"eval","passed":32,"failed":0,"total":32},
     {"name":"builtins","passed":20,"failed":0,"total":20},
     {"name":"semi_naive","passed":8,"failed":0,"total":8},
     {"name":"negation","passed":10,"failed":0,"total":10},
@@ -16,5 +16,5 @@
     {"name":"magic","passed":28,"failed":0,"total":28},
     {"name":"demo","passed":21,"failed":0,"total":21}
   ],
-  "generated": "2026-05-08T14:07:50+00:00"
+  "generated": "2026-05-08T14:12:22+00:00"
 }

lib/datalog/scoreboard.md

@@ -1,13 +1,13 @@
 # datalog scoreboard
 
-**230 / 230 passing** (0 failure(s)).
+**231 / 231 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
 | tokenize | 26 | 26 | ok |
 | parse | 18 | 18 | ok |
 | unify | 28 | 28 | ok |
-| eval | 31 | 31 | ok |
+| eval | 32 | 32 | ok |
 | builtins | 20 | 20 | ok |
 | semi_naive | 8 | 8 | ok |
 | negation | 10 | 10 | ok |

lib/datalog/tests/eval.sx

@@ -273,6 +273,19 @@
           (dl-saturated? db))
         false)
 
+      ;; Disjunction via multiple rules — Datalog has no `;` in
+      ;; body, so disjunction is expressed as separate rules with
+      ;; the same head. Here plant_based(X) is satisfied by either
+      ;; vegan(X) or vegetarian(X).
+      (dl-et-test-set! "disjunction via multiple rules"
+        (dl-query
+          (dl-program
+            "vegan(alice). vegetarian(bob). meat_eater(carol).
+             plant_based(X) :- vegan(X).
+             plant_based(X) :- vegetarian(X).")
+          (list (quote plant_based) (quote X)))
+        (list {:X (quote alice)} {:X (quote bob)}))
+
       ;; Bipartite-style join: pair-of-friends who share a hobby.
       ;; Three-relation join exercising the planner's join order.
       (dl-et-test-set! "bipartite friends-with-hobby"