/** Unify goal: pred1(X,[1|Z]|Z) rule: pred1(V,[1,2,3,4],2,3|U):-pred2(V|U). */
@Test
public void unifyNonEmptyListTest() {
ProvaKnowledgeBase kb = new ProvaKnowledgeBaseImpl();
ProvaConstant c1 = ProvaConstantImpl.create(1);
ProvaVariable z = ProvaVariableImpl.create("Z");
ProvaList l1 = ProvaListImpl.create(new ProvaObject[] {c1}, z);
ProvaVariable x = ProvaVariableImpl.create("X");
ProvaList l2 = ProvaListImpl.create(new ProvaObject[] {x, l1}, z);
ProvaLiteral query = kb.generateLiteral("pred1", l2);
ProvaRule goal = kb.generateGoal(new ProvaLiteral[] {query});
ProvaConstant c2 = ProvaConstantImpl.create(2);
ProvaConstant c3 = ProvaConstantImpl.create(3);
ProvaConstant c4 = ProvaConstantImpl.create(4);
ProvaList l3 = ProvaListImpl.create(new ProvaObject[] {c1, c2, c3, c4});
ProvaVariable v = ProvaVariableImpl.create("V");
ProvaVariable u = ProvaVariableImpl.create("U");
ProvaList l4 = ProvaListImpl.create(new ProvaObject[] {v, l3, c2, c3}, u);
ProvaLiteral lit1 = kb.generateLiteral("pred1", l4);
ProvaList l5 = ProvaListImpl.create(new ProvaObject[] {v}, u);
ProvaLiteral lit2 = kb.generateLiteral("pred2", l5);
ProvaRule rule = kb.generateRule(lit1, new ProvaLiteral[] {lit2});
ProvaUnificationImpl unification = new ProvaUnificationImpl(goal, rule);
boolean result = unification.unify();
org.junit.Assert.assertTrue(result);
int countSourceSubstitutions = 0;
for (ProvaVariable var : unification.getSourceVariables()) {
ProvaObject to = var.getRecursivelyAssigned();
if (to != var) {
countSourceSubstitutions++;
}
}
org.junit.Assert.assertEquals(countSourceSubstitutions, 1);
int countTargetSubstitutions = 0;
for (ProvaVariable var : unification.getTargetVariables()) {
ProvaObject to = var.getRecursivelyAssigned();
if (to != var) {
countTargetSubstitutions++;
}
}
org.junit.Assert.assertEquals(countTargetSubstitutions, 2);
// Recover actual substitutions resulting from the unification
ProvaLiteral[] newGoals = unification.rebuildNewGoals();
org.junit.Assert.assertNotNull(newGoals);
// There is one actual goal: pred2(X,4)
org.junit.Assert.assertEquals(newGoals.length, 1);
// The goal literal has fixed arity of 2
org.junit.Assert.assertEquals(newGoals[0].getTerms().computeSize(), 2);
// The "fixed" part of the goal literal has length equal to 2
org.junit.Assert.assertEquals(newGoals[0].getTerms().getFixed().length, 2);
}
/** Unify goal: pred1(X,[2|A]|Z) rule: pred1(V,Y,3,Y,U):-pred2(V|Y). */
@Test
public void unifyTest2() {
ProvaKnowledgeBase kb = new ProvaKnowledgeBaseImpl();
ProvaConstant c2 = ProvaConstantImpl.create(2);
ProvaVariable a = ProvaVariableImpl.create("A");
ProvaList l1 = ProvaListImpl.create(new ProvaObject[] {c2}, a);
ProvaVariable x = ProvaVariableImpl.create("X");
ProvaVariable z = ProvaVariableImpl.create("Z");
ProvaList l2 = ProvaListImpl.create(new ProvaObject[] {x, l1}, z);
ProvaLiteral query = kb.generateLiteral("pred1", l2);
ProvaRule goal = kb.generateGoal(new ProvaLiteral[] {query});
ProvaVariable v = ProvaVariableImpl.create("V");
ProvaVariable y = ProvaVariableImpl.create("Y");
ProvaConstant c4 = ProvaConstantImpl.create(3);
ProvaVariable u = ProvaVariableImpl.create("U");
ProvaList l3 = ProvaListImpl.create(new ProvaObject[] {v, y, c4, y, u});
ProvaLiteral lit1 = kb.generateLiteral("pred1", l3);
ProvaList l4 = ProvaListImpl.create(new ProvaObject[] {v}, y);
ProvaLiteral lit3 = kb.generateLiteral("pred2", l4);
ProvaRule rule = kb.generateRule(lit1, new ProvaLiteral[] {lit3});
ProvaUnificationImpl unification = new ProvaUnificationImpl(goal, rule);
boolean result = unification.unify();
org.junit.Assert.assertTrue(result);
int countSourceSubstitutions = 0;
for (ProvaVariable var : unification.getSourceVariables()) {
ProvaObject to = var.getRecursivelyAssigned();
if (to != var) {
countSourceSubstitutions++;
}
}
org.junit.Assert.assertEquals(countSourceSubstitutions, 1);
int countTargetSubstitutions = 0;
for (ProvaVariable var : unification.getTargetVariables()) {
ProvaObject to = var.getRecursivelyAssigned();
if (to != var) {
countTargetSubstitutions++;
}
}
org.junit.Assert.assertEquals(countTargetSubstitutions, 2);
// Recover actual substitutions resulting from the unification
ProvaLiteral[] newGoals = unification.rebuildNewGoals();
org.junit.Assert.assertNotNull(newGoals);
// There is one actual goal: pred2(X,2|A)
org.junit.Assert.assertEquals(newGoals.length, 1);
// The goal literal has variable arity
org.junit.Assert.assertEquals(newGoals[0].getTerms().computeSize(), -1);
// The second argument "2" is added to the "fixed" part of the goal literal
org.junit.Assert.assertEquals(newGoals[0].getTerms().getFixed().length, 2);
}