From 21205946948514433c83e24bc92187f0f69320ad Mon Sep 17 00:00:00 2001
From: Pepijn de Vos <pepijndevos@gmail.com>
Date: Sat, 28 May 2011 21:30:44 +0200
Subject: [PATCH] rel, defrel, extend-rel

---
 src/main/clojure/clojure/core/logic/prelude.clj |   51 ++++++++++++-----------
 src/test/clojure/clojure/core/logic/tests.clj   |   34 ++++++++--------
 2 files changed, 44 insertions(+), 41 deletions(-)

diff --git a/src/main/clojure/clojure/core/logic/prelude.clj b/src/main/clojure/clojure/core/logic/prelude.clj
index 8476faf..2ccf1f2 100644
--- a/src/main/clojure/clojure/core/logic/prelude.clj
+++ b/src/main/clojure/clojure/core/logic/prelude.clj
@@ -102,29 +102,6 @@
        (apply merge-with
               (fn [a b] (set/union a b)))))
 
-(defmacro defrel [name & args]
-  (let [setsym (symbol (str name "-set"))
-        idxsym (symbol (str name "-indexed"))]
-    `(do
-       (def ~setsym (atom #{}))
-       (def ~idxsym (atom {}))
-       (defmacro ~name [~@args]
-         (defrelg '~setsym '~idxsym ~@args)))))
-
-(defn defrelg [setsym idxsym & args]
-  `(fn [a#]
-     (answers a# (deref ~setsym) (deref ~idxsym) [~@args])))
-
-;; NOTE: put in a dosync?
-
-(defmacro fact [rel & tuple]
-  (let [setsym (symbol (str rel "-set"))
-        idxsym (symbol (str rel "-indexed"))]
-    `(do
-       (swap! ~setsym conj [~@tuple])
-       (reset! ~idxsym (index @~setsym))
-       nil)))
-
 (defn to-stream [aseq]
   (when (seq aseq)
     (choice (first aseq)
@@ -140,4 +117,30 @@
           (map (fn [cand]
                  (when-let [a (unify a t cand)]
                    a)))
-          (remove nil?)))))
\ No newline at end of file
+          (remove nil?)))))
+
+(defn rel
+  ([values] (rel values (index values)))
+  ([values idx] (partial rel values idx))
+  ([values idx names]
+    (fn goal [a]
+      (answers a values idx names))))
+
+(defprotocol PRel
+  (fact [this tuple])
+  (extend-rel [this tuples]))
+
+(deftype Rel [st idx]
+  PRel
+  (fact [_ tuple]
+    (swap! st conj tuple)
+    (reset! idx (index @st)))
+  (extend-rel [_ tuples]
+    (swap! st into tuples)
+    (reset! idx (index @st)))
+  clojure.lang.IFn
+  (invoke [_ tuples]
+    (rel @st @idx tuples)))
+
+(defmacro defrel [rname index] ; args will be used for indexing
+  `(def ~rname (Rel. (atom #{}) (atom {}))))
diff --git a/src/test/clojure/clojure/core/logic/tests.clj b/src/test/clojure/clojure/core/logic/tests.clj
index 5996b02..94fb2b4 100644
--- a/src/test/clojure/clojure/core/logic/tests.clj
+++ b/src/test/clojure/clojure/core/logic/tests.clj
@@ -995,30 +995,30 @@
 ;; -----------------------------------------------------------------------------
 ;; rel
 
-(defrel man p)
+(defrel man [p])
 
-(fact man 'Bob)
-(fact man 'John)
-(fact man 'Ricky)
+(fact man ['Bob])
+(fact man ['John])
+(fact man ['Ricky])
 
-(defrel woman p)
-(fact woman 'Mary)
-(fact woman 'Martha)
-(fact woman 'Lucy)
+(defrel woman [p])
+(fact woman ['Mary])
+(fact woman ['Martha])
+(fact woman ['Lucy])
 
-(defrel likes p1 p2)
-(fact likes 'Bob 'Mary)
-(fact likes 'John 'Martha)
-(fact likes 'Ricky 'Lucy)
+(defrel likes [p1 p2])
+(fact likes ['Bob 'Mary])
+(fact likes ['John 'Martha])
+(fact likes ['Ricky 'Lucy])
 
-(defrel fun p)
-(fact fun 'Lucy)
+(defrel fun [p])
+(fact fun ['Lucy])
 
 (deftest test-rel-1
   (is (= (run* [q]
            (exist [x y]
-             (likes x y)
-             (fun y)
+             (likes [x y])
+             (fun [y])
              (== q [x y])))
          '([Ricky Lucy]))))
 
@@ -1093,4 +1093,4 @@
 
   (def test-expr (prep '(?x 1 ?x)))
   (unifier test-expr test-expr)
-  )
\ No newline at end of file
+  )
-- 
1.7.5.1