mod: Ext 1 — negation-as-failure conditions (:not / :attr), 146/146

Report attributes (:attrs) project to attr(Id, name) facts; policy gains (:attr x)
and (:not <cond>) conditions. The Prolog substrate exposes negation as a functor
not(Goal) (the prefix \+ operator doesn't parse here). Closed-world example:
hide spam unless author verified. Default policy untouched — feature proven via
custom rule sets, so all 132 base tests stay green. +14 extension tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/mod/schema.sx

@@ -1,12 +1,13 @@
 ;; lib/mod/schema.sx — report representation + Prolog fact generation.
 ;;
-;; A report is a dict {:id :by :about :reason :evidence}. :evidence is a list of
-;; accumulated evidence entries {:kind :val} (human review, automated scanners,
-;; etc.). The engine derives keyword classifications from the reason text and
-;; projects the report, its classifications, and its accumulated evidence into
-;; Prolog facts that policy clauses match against.
+;; A report is a dict {:id :by :about :reason :evidence :attrs}. :evidence is a
+;; list of accumulated evidence entries {:kind :val} (human review, automated
+;; scanners). :attrs is a list of attribute names (e.g. "verified") used by
+;; negation-as-failure conditions. The engine derives keyword classifications
+;; from the reason text and projects the report, its classifications, evidence,
+;; and attributes into Prolog facts that policy clauses match against.
 
-(define mod/mk-report (fn (id by about reason) {:id id :by by :evidence (list) :about about :reason reason}))
+(define mod/mk-report (fn (id by about reason) {:attrs (list) :id id :by by :evidence (list) :about about :reason reason}))
 
 (define mod/report-id (fn (r) (get r :id)))
 (define mod/report-by (fn (r) (get r :by)))
@@ -17,11 +18,23 @@
   mod/report-evidence
   (fn (r) (let ((e (get r :evidence))) (if (nil? e) (list) e))))
 
+(define
+  mod/report-attrs
+  (fn (r) (let ((a (get r :attrs))) (if (nil? a) (list) a))))
+
 (define mod/mk-evidence (fn (kind val) {:val val :kind kind}))
 (define mod/evidence-kind (fn (e) (get e :kind)))
 (define mod/evidence-val (fn (e) (get e :val)))
 
-(define mod/with-evidence (fn (r evs) {:id (mod/report-id r) :by (mod/report-by r) :evidence evs :about (mod/report-about r) :reason (mod/report-reason r)}))
+(define mod/report* (fn (r evs attrs) {:attrs attrs :id (mod/report-id r) :by (mod/report-by r) :evidence evs :about (mod/report-about r) :reason (mod/report-reason r)}))
+
+(define
+  mod/with-evidence
+  (fn (r evs) (mod/report* r evs (mod/report-attrs r))))
+
+(define
+  mod/with-attrs
+  (fn (r attrs) (mod/report* r (mod/report-evidence r) attrs)))
 
 (define
   mod/attach-evidence
@@ -29,6 +42,10 @@
     (r e)
     (mod/with-evidence r (append (mod/report-evidence r) (list e)))))
 
+(define
+  mod/attach-attr
+  (fn (r a) (mod/with-attrs r (append (mod/report-attrs r) (list a)))))
+
 ;; ── substring search (the prolog-loaded env lacks includes?; slice/len do work) ──
 
 (define
@@ -139,6 +156,12 @@
             ")."))
         evs))))
 
+(define
+  mod/attr-facts
+  (fn
+    (id attrs)
+    (mod/join-with "\n" (map (fn (a) (str "attr(" id ", " a ").")) attrs))))
+
 (define
   mod/report-facts
   (fn
@@ -149,11 +172,13 @@
         (about (mod/pl-quote (mod/report-about r))))
       (let
         ((cls (mod/classification-facts id (mod/classify-keywords r)))
-          (evs (mod/evidence-facts id (mod/report-evidence r))))
+          (evs (mod/evidence-facts id (mod/report-evidence r)))
+          (ats (mod/attr-facts id (mod/report-attrs r))))
         (mod/join-with
           "\n"
           (list
             (str "report(" id ", " by ", " about ").")
             (str "report_count(" about ", " count ").")
             cls
-            evs))))))
+            evs
+            ats))))))