public static Clause ApplySubstitution(Clause X, Substitution T)
{
for (int i = 0; i < X.literal.Count; i++)
{
X.literal[i] = Literal.ApplySubstitution(X.literal[i], T);
}
return(X);
}
public static Literal ApplySubstitution(Literal A, Substitution T)
{
String oldLiteral = A.Compose();
for (int i = 0; i < T.replacementList.Count; i++)
{
Replacement R = T.replacementList[i];
String varName = R.X.name;
oldLiteral = oldLiteral.Replace(varName, R.t.Compose());
}
return(Literal.Decompose(oldLiteral));
}
public SolutionStep(Goal g, Clause c, Substitution theta)
{
this.goal = g.Compose();
this.clause = c.Compose();
this.substitution = theta.Compose();
}
public static void Solve(Goal goal)
{
// End condition
if (_LOOP_IDENTIFIER_ <= 0)
{
//solutionFound = true;
//solution = new List<SolutionStep>();
//solution.Add(new SolutionStep());
return;
}
else
{
if (goal.IsEmpty() && !solutionFound)
{
solutionFound = true;
solution.Add(new SolutionStep());
}
// Find solution using back-tracking
for (int i = 0; i < goal.literal.Count && !solutionFound; i++)
{
Literal Ai = goal.literal[i];
for (int j = 0; j < logicProgram.Count && !solutionFound; j++)
{
Literal Bj = logicProgram[j].literal[0];
Substitution thetai = Solver.Unify(Ai, Bj);
if (thetai != null && thetai.isValid())
{
// Log solution step
solution.Add(new SolutionStep(goal, logicProgram[j], thetai));
// Backup current goal
//Literal backup = goal.literal[i];
Goal backupGoal = Lib.DeepClone <Goal>(goal);
// Change goal
goal.literal.RemoveAt(i);
goal.literal.InsertRange(i, logicProgram[j].literal.GetRange(1, logicProgram[j].literal.Count - 1));
goal = Goal.ApplySubstitution(goal, thetai);
_LOOP_IDENTIFIER_--;
// ====================== Recursive call
Solve(goal);
// ====================== Recursive call
_LOOP_IDENTIFIER_++;
if (!solutionFound)
{
// Restore goal
//goal.literal.RemoveRange(i, logicProgram[j].literal.Count - 1);
//goal.literal.Insert(i, backup);
goal = backupGoal;
// Remove solution step
solution.RemoveAt(solution.Count - 1);
}
}
}
}
}
}
