Assert{a,z,}

src/prolog/builtins/databaseOperators.kt

@@ -0,0 +1,38 @@
+package prolog.builtins
+
+import prolog.Answers
+import prolog.Substitutions
+import prolog.ast.logic.Clause
+import prolog.ast.terms.Atom
+import prolog.ast.terms.Structure
+import prolog.ast.logic.Predicate
+import prolog.Program
+import prolog.ast.terms.Functor
+
+class Assert(clause: Clause) : AssertZ(clause) {
+    override val functor: Functor = "assert/1"
+}
+
+/**
+ * Assert a [Clause] as a first clause of the [Predicate] into the [Program].
+ */
+class AssertA(val clause: Clause) : Structure(Atom("asserta"), listOf(clause)) {
+    override fun satisfy(subs: Substitutions): Answers {
+        // Add clause to the program
+        Program.load(listOf(clause), 0)
+
+        return sequenceOf(Result.success(emptyMap()))
+    }
+}
+
+/**
+ * Assert a [Clause] as a last clause of the [Predicate] into the [Program].
+ */
+open class AssertZ(val clause: Clause) : Structure(Atom("assertz"), listOf(clause)) {
+    override fun satisfy(subs: Substitutions): Answers {
+        // Add clause to the program
+        Program.load(listOf(clause))
+
+        return sequenceOf(Result.success(emptyMap()))
+    }
+}