Handle queries with all-constant functors

src/main/scala/pl/edu/agh/kis/eis/ndl/BindingSetX.scala

@@ -15,6 +15,9 @@ object BindingSet {
       case Seq(_: Const[A]) =>
         BindingSetX(Map.empty)
 
+      case Seq(_: Const[A], _: Const[A]) =>
+        BindingSetX(Map.empty)
+
       case Seq(v1: Variable[A], v2: Variable[A]) =>
         BindingSetX(Map(
           v1.name.get -> kb.facts2.map(_._1),
@@ -26,7 +29,6 @@ object BindingSet {
 
 case class BindingSetX[A](m: Map[String, Set[A]]) {
   def expand(bs: BindingSetX[A]): BindingSetX[A] = {
-    // tutaj zbiór jest tworzony zbyt duży
     BindingSetX(m ++ bs.m.map { case (k, v) => k -> (v intersect m.getOrElse(k, v)) })
   }
 }

src/main/scala/pl/edu/agh/kis/eis/ndl/FactSelector.scala

@@ -25,7 +25,7 @@ trait FactSelector[A] {
 
     // calculate all possible variable configurations
     crossJoin(getBindingSetVars(bindingSet)).map(_.toSet)
-      // bind all variables in query
+      // bind all variables in query (adds all-constant facts from query too)
       .map(bind).toSet
       // build facts from bound query and remove facts without evidence in kb
       .filter(buildableToKnownFact)

src/test/scala/pl/edu/agh/kis/eis/ndl/KnowledgeBaseSpec.scala

@@ -162,9 +162,39 @@ class KnowledgeBaseSpec extends FlatSpec with Matchers {
     )
   }
 
-  "Query ((x 1) (y 2))" should "be unified" ignore {
+  "Query ((x) (y) (z z))" should "be unified" in {
+    val kb: KnowledgeBase[Int] = new KnowledgeBase[Int](Set(
+      Tuple1(6), (3, 4), (4, 4), Tuple1(3), (6, 6)
+    ))
+
+    val x = Variable[Int]("x")
+    val y = Variable[Int]("y")
+    val z = Variable[Int]("z")
+    kb.queryAll(Functor(x), Functor(y), Functor(z, z)).toSeq should contain theSameElementsAs Set(
+      Set(Variable("x", 6), Variable("y", 6), Variable("z", 4)),
+      Set(Variable("x", 6), Variable("y", 3), Variable("z", 4)),
+      Set(Variable("x", 3), Variable("y", 6), Variable("z", 4)),
+      Set(Variable("x", 3), Variable("y", 3), Variable("z", 4)),
+      Set(Variable("x", 6), Variable("y", 6), Variable("z", 6)),
+      Set(Variable("x", 6), Variable("y", 3), Variable("z", 6)),
+      Set(Variable("x", 3), Variable("y", 6), Variable("z", 6)),
+      Set(Variable("x", 3), Variable("y", 3), Variable("z", 6))
+    )
+  }
+
+  "Query ((x) (3))" should "fail to unify on nonexistent unary fact" in {
+    val kb: KnowledgeBase[Int] = new KnowledgeBase[Int](Set(
+      Tuple1(5), (1, 3)
+    ))
+
+    kb.queryAll(Functor(Variable("x")), Functor(Const(3))) should be(empty)
   }
 
-  "Query ((x) (y) (z z))" should "be unified" ignore {
+  "Query ((x) (4 5))" should "fail to unify on nonexistent binary fact" in {
+    val kb: KnowledgeBase[Int] = new KnowledgeBase[Int](Set(
+      Tuple1(1), (2, 5), Tuple1(4)
+    ))
+
+    kb.queryAll(Functor(Variable("x")), Functor(Const(4), Const(5))) should be(empty)
   }
 }