Mantis#1931. Thank you kindly, Kinoc for a patch that:

* Yield Prolog 1.0.1 Released : it passes all but 9 of the 
421 tests in the ISO Prolog test suite (97.8%) .
* support dynamic predicates and rules.
* support 'import' to use external static functions 
improves connection to C# functions
* Matches Yield Prolog r831

OpenSim/Region/ScriptEngine/Shared/Api/Runtime/YieldProlog/Functor1.cs

@@ -49,6 +49,17 @@ namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog
         {
         }
 
+        // disable warning on l1, don't see how we can
+        // code this differently
+        #pragma warning disable 0168
+        /// <summary>
+        /// If arg is another Functor1, then succeed (yield once) if this and arg have the
+        /// same name and the functor args unify, otherwise fail (don't yield).
+        /// If arg is a Variable, then call its unify to unify with this.
+        /// Otherwise fail (don't yield).
+        /// </summary>
+        /// <param name="arg"></param>
+        /// <returns></returns>
         public IEnumerable<bool> unify(object arg)
         {
             arg = YP.getValue(arg);
@@ -57,25 +68,18 @@ namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog
                 Functor1 argFunctor = (Functor1)arg;
                 if (_name.Equals(argFunctor._name))
                 {
-                    // disable warning on l1, don't see how we can
-                    // code this differently
-                    #pragma warning disable 0168
                     foreach (bool l1 in YP.unify(_arg1, argFunctor._arg1))
                         yield return false;
-                    #pragma warning restore 0168
                 }
             }
             else if (arg is Variable)
             {
-                // disable warning on l1, don't see how we can
-                // code this differently
-                #pragma warning disable 0168
                 foreach (bool l1 in ((Variable)arg).unify(this))
                     yield return false;
-                #pragma warning restore 0168
-
             }
         }
+        #pragma warning restore 0168
+
 
         public override string ToString()
         {