Added better assertion checking on data types

Author: Paula Gearon

src/naga/rules.clj

@@ -19,6 +19,11 @@
  [x]
  (and (symbol? x) (= \% (first (name x)))))
 
+(defn- vars [constraint]
+ (if (list? constraint)
+ (filter st/vartest? (rest constraint))
+ (st/vars constraint)))
+
 (defn mark-unbound
  "Convert a head to use fresh vars for any vars that are unbound.
  Scans the vars in the body to identify which vars are unbound."
@@ -37,6 +42,8 @@
  "Body must be a sequence of constraints")
  (assert (and (sequential? head) (or (empty? head) (every? sequential? head)))
  "Head must be a sequence of constraints")
+ (assert (every? (complement fresh-var?) (mapcat vars body))
+ "Fresh vars are not allowed in a body")
  (st/new-rule (mark-unbound head body) body name)))
 
 (s/defn named-rule :- Rule