Added datalog

1 files changed, 61 insertions, 0 deletions

diff --git a/src/clojure/contrib/datalog.clj b/src/clojure/contrib/datalog.clj
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+;;  Copyright (c) Jeffrey Straszheim. All rights reserved.  The use and
+;;  distribution terms for this software are covered by the Eclipse Public
+;;  License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can
+;;  be found in the file epl-v10.html at the root of this distribution.  By
+;;  using this software in any fashion, you are agreeing to be bound by the
+;;  terms of this license.  You must not remove this notice, or any other,
+;;  from this software.
+;;
+;;  datalog.clj
+;;
+;;  A Clojure implementation of Datalog
+;;
+;;  straszheimjeffrey (gmail)
+;;  Created 2 March 2009
+
+
+;;; Please see the example.clj file in the datalog folder
+
+
+(ns clojure.contrib.datalog
+  (:use clojure.contrib.datalog.rules
+        clojure.contrib.datalog.softstrat
+        clojure.contrib.datalog.database)
+  (:use [clojure.set :only (intersection)]
+        [clojure.contrib.except :only (throwf)]))
+
+(defstruct work-plan
+  :work-plan        ; The underlying structure
+  :rules            ; The original rules
+  :query            ; The original query
+  :work-plan-type)  ; The type of plan
+
+(defn- validate-work-plan
+  "Ensure any top level semantics are not violated"
+  [work-plan database]
+  (let [common-relations (-> work-plan :rules (intersection (-> database keys set)))]
+    (when (-> common-relations
+              empty?
+              not)
+      (throwf "The rules and database define the same relation(s): %s" common-relations))))
+  ; More will follow
+
+(defn build-work-plan
+  "Given a list of rules and a query, build a work plan that can be
+   used to execute the query."
+  [rules query]
+  (struct-map work-plan
+    :work-plan (build-soft-strat-work-plan rules query)
+    :rules rules
+    :query query
+    :work-plan-type ::soft-stratified))
+
+(defn run-work-plan
+  "Given a work plan, a database, and some query bindings, run the
+   work plan and return the results."
+  [work-plan database query-bindings]
+  (validate-work-plan work-plan database)
+  (evaluate-soft-work-set (:work-plan work-plan) database query-bindings))
+
+
+;; End of file