From 7a64be22d8af17e5c5b302020a365d339ea41405 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Fri, 8 May 2026 10:19:58 +0000
Subject: [PATCH] =?UTF-8?q?datalog:=20dl-eval=20=E2=89=A1=20dl-eval-magic?=
 =?UTF-8?q?=20equivalence=20test=20(215/215)?=
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---
 lib/datalog/scoreboard.json |  8 ++++----
 lib/datalog/scoreboard.md   |  4 ++--
 lib/datalog/tests/api.sx    | 14 ++++++++++++++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/lib/datalog/scoreboard.json b/lib/datalog/scoreboard.json
index c34b0adb..26342bda 100644
--- a/lib/datalog/scoreboard.json
+++ b/lib/datalog/scoreboard.json
@@ -1,8 +1,8 @@
 {
   "lang": "datalog",
-  "total_passed": 214,
+  "total_passed": 215,
   "total_failed": 0,
-  "total": 214,
+  "total": 215,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":18,"failed":0,"total":18},
@@ -12,9 +12,9 @@
     {"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":19,"failed":0,"total":19},
+    {"name":"api","passed":20,"failed":0,"total":20},
     {"name":"magic","passed":22,"failed":0,"total":22},
     {"name":"demo","passed":18,"failed":0,"total":18}
   ],
-  "generated": "2026-05-08T10:17:32+00:00"
+  "generated": "2026-05-08T10:19:48+00:00"
 }
diff --git a/lib/datalog/scoreboard.md b/lib/datalog/scoreboard.md
index 8633cec0..c97ea81e 100644
--- a/lib/datalog/scoreboard.md
+++ b/lib/datalog/scoreboard.md
@@ -1,6 +1,6 @@
 # datalog scoreboard
 
-**214 / 214 passing** (0 failure(s)).
+**215 / 215 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -12,6 +12,6 @@
 | semi_naive | 8 | 8 | ok |
 | negation | 10 | 10 | ok |
 | aggregates | 18 | 18 | ok |
-| api | 19 | 19 | ok |
+| api | 20 | 20 | ok |
 | magic | 22 | 22 | ok |
 | demo | 18 | 18 | ok |
diff --git a/lib/datalog/tests/api.sx b/lib/datalog/tests/api.sx
index 7cddd4cb..b46df8f8 100644
--- a/lib/datalog/tests/api.sx
+++ b/lib/datalog/tests/api.sx
@@ -261,6 +261,20 @@
           "?- ancestor(a, X).")
         (list {:X (quote b)} {:X (quote c)}))
 
+      ;; Equivalence: dl-eval and dl-eval-magic produce the same
+      ;; answers for any well-formed query (magic-sets is a perf
+      ;; alternative, not a semantic change).
+      (dl-api-test! "dl-eval ≡ dl-eval-magic on ancestor"
+        (let
+          ((source "parent(a, b). parent(b, c). parent(c, d).
+                    ancestor(X, Y) :- parent(X, Y).
+                    ancestor(X, Z) :- parent(X, Y), ancestor(Y, Z)."))
+          (let
+            ((semi (dl-eval source "?- ancestor(a, X)."))
+              (magic (dl-eval-magic source "?- ancestor(a, X).")))
+            (= (len semi) (len magic))))
+        true)
+
       ;; Comprehensive integration: recursion + stratified negation
       ;; + aggregation + comparison composed in a single program.
       ;; (Uses _Anything as a regular var instead of `_` so the