feat(declarativeDSL): programTheory is now an alias of dynamicTheory

Author: kelvin-olaiya

src/main/scala/io/github/kelvindev15/prolog/core/Struct.scala

@@ -162,6 +162,6 @@ object Struct:
 
     private case class FactImpl(_head: Struct) extends Fact:
       override val head: Option[Struct] = Option(_head)
-      override val arguments: Seq[Term] = Seq(head.get)
+      override val arguments: Seq[Term] = Seq(head.get, body)
       override def isGround: Boolean = head.get.isGround
       override def variables: Seq[Variable] = head.get.variables

src/main/scala/io/github/kelvindev15/prolog/dsl/DeclarativeProlog.scala

@@ -25,6 +25,7 @@ trait DeclarativeProlog:
     prologProgram
 
   /** Sets the static theory of a [[PrologProgram]].
+    * Warning: it overrides any previously static theory set in the program.
     *
     * @param program
     *   the program whose static theory has to be set.
@@ -40,6 +41,7 @@ trait DeclarativeProlog:
     prologProgram = program.setStaticTheory(t.theory)
 
   /** Sets the dynamic theory of a [[PrologProgram]].
+    * Warning: it overrides any previously dynamic theory set in the program.
     *
     * @param program
     *   the program whose dynamic theory has to be set.
@@ -54,6 +56,22 @@ trait DeclarativeProlog:
     theory
     prologProgram = prologProgram.setDynamicTheory(t.theory)
 
+  /** Alias of [[dynamicTheory]]. Sets the dynamic theory of a [[PrologProgram]].
+   * Warning: it overrides any previously dynamic theory set in the program.
+   *
+   * @param program
+   * the program whose dynamic theory has to be set.
+   * @param theory
+   * a function that takes a [[MutableDynamicTheoryWrapper]] as a context
+   * parameter and operates on it e.g to add or remove clauses.
+   */
+  def programTheory(using program: PrologProgram)(
+    theory: MutableDynamicTheoryWrapper ?=> Unit
+  ): Unit =
+    given t: MutableDynamicTheoryWrapper = MutableDynamicTheoryWrapper()
+    theory
+    prologProgram = prologProgram.setDynamicTheory(t.theory)  
+
   /** Add an assert(X) clause to the [[dynamicTheory]] provided as a context
     * parameter.
     *

src/test/scala/io/github/kelvindev15/prolog/dsl/TestDeclarativePrologDSL.scala

@@ -104,3 +104,9 @@ class TestDeclarativePrologDSL
         Struct(Atom("="), Cons(Variable("H"), Variable("T")), Variable("S"))
       )
     )
+
+  test("Using programTheory as dynamic theory alias"):
+    prolog {
+      programTheory:
+        fact { "likes"(X) }
+    }.dynamicTheory shouldBe Seq(Fact(Struct(Atom("likes"), Variable("X"))))