From 30fcd69dd4c9ca86b3a73c3f6b5866d6b943ddff Mon Sep 17 00:00:00 2001
From: David Nolen <david.nolen@gmail.com>
Date: Sun, 5 May 2013 20:32:30 -0400
Subject: [PATCH] LOGIC-132: "PMap is non-storable" exception when using
 featurec with nested feature map.

The recursive `featurec` support was a bit naive. `unify-with-pmap*`
nows handles the various cases properly.
---
 src/main/clojure/clojure/core/logic.clj       | 23 +++++++--------
 src/test/clojure/clojure/core/logic/tests.clj | 29 +++++++++++++++++++
 2 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/src/main/clojure/clojure/core/logic.clj b/src/main/clojure/clojure/core/logic.clj
index a6f2208a..75962674 100644
--- a/src/main/clojure/clojure/core/logic.clj
+++ b/src/main/clojure/clojure/core/logic.clj
@@ -2573,6 +2573,8 @@
 ;; =============================================================================
 ;; Partial Maps
 
+(declare featurec partial-map)
+
 (defn unify-with-pmap* [u v s]
   (loop [ks (keys u) s s]
     (if (seq ks)
@@ -2581,9 +2583,14 @@
         (if (= vf ::not-found)
           nil
           (let [uf (get u kf)]
-            (if-let [s (unify s uf vf)]
-              (recur (next ks) s)
-              nil))))
+            (if (lvar? vf)
+              (recur (next ks) ((featurec vf uf) s))
+              (if (map? uf)
+                (if-let [s (unify s (partial-map uf) vf)]
+                  (recur (next ks) s))
+                (if-let [s (unify s uf vf)]
+                  (recur (next ks) s)
+                  nil))))))
       s)))
 
 (declare partial-map?)
@@ -2644,21 +2651,13 @@
     IConstraintWatchedStores
     (-watched-stores [this] #{::subst})))
 
-(defn ->feature [x]
-  (-feature
-    (walk-term x
-      (fn [y]
-        (if (tree-term? y)
-          (->feature y)
-          y)))))
-
 (defn featurec
   "Ensure that a map contains at least the key-value pairs
   in the map fs. fs must be partially instantiated - that is, 
   it may contain values which are logic variables to support 
   feature extraction."
   [x fs]
-  (cgoal (-featurec x (->feature fs))))
+  (cgoal (-featurec x (partial-map fs))))
 
 ;; =============================================================================
 ;; defnc
diff --git a/src/test/clojure/clojure/core/logic/tests.clj b/src/test/clojure/clojure/core/logic/tests.clj
index 54b55ad5..68024182 100644
--- a/src/test/clojure/clojure/core/logic/tests.clj
+++ b/src/test/clojure/clojure/core/logic/tests.clj
@@ -1741,10 +1741,22 @@
            (featurec x {:foo {:bar y}})
            (== x {:foo {:bar 1}}))
         '([{:foo {:bar 1}} 1])))
+  (is (= (run* [x y]
+           (== x {:foo {:bar 1}})
+           (featurec x {:foo {:bar y}}))
+        '([{:foo {:bar 1}} 1])))
   (is (= (run* [x y]
            (featurec x {:foo {:bar y}})
            (== x {:foo {:bar 1 :woz 2}}))
         '([{:foo {:bar 1 :woz 2}} 1])))
+  (is (= (run* [x y]
+           (== x {:foo {:bar 1 :woz 2}})
+           (featurec x {:foo {:bar y}}))
+        '([{:foo {:bar 1 :woz 2}} 1])))
+  (is (= (run* [x y]
+           (== x {:foo {:baz 1}})
+           (featurec x {:foo {:bar y}}))
+        '()))
   (is (= (run* [x y]
            (featurec x {:foo {:bar y}})
            (== x {:foo {:baz 1}}))
@@ -1810,6 +1822,23 @@
              (fd/in x y z (fd/interval 0 9))))
          '([6 3]))))
 
+(deftest test-logic-132-recursive-featurec
+  (is (= (run* [x y]
+           (featurec x {:a {:b 1}})
+           (== y {:b 1})
+           (== x {:a y}))
+        '([{:a {:b 1}} {:b 1}])))
+  (is (= (run* [x y]
+           (featurec x {:a {:b 1}})
+           (== x {:a y})
+           (== y {:b 1}))
+        '([{:a {:b 1}} {:b 1}])))
+  (is (= (run* [x y]
+           (== x {:a y})
+           (== y {:b 1})
+           (featurec x {:a {:b 1}}))
+        '([{:a {:b 1}} {:b 1}]))))
+
 ;; =============================================================================
 ;; cKanren