static public RuleData ToRules(List <Token> input)
{
var output = new RuleData();
var currentTerm = new Term();
output.Terms.Add(currentTerm);
currentTerm.Id = output.Terms.Count;
while (input.Count > 0)
{
var currentAtom = new Atom();
currentTerm.Atoms.Add(currentAtom);
//negativeness
if (input[0].Type == TokenType.Negate)
{
currentAtom.Truthfulness = false;
TokenPop(input);
}
//name
var nameToken = TokenPop(input);
Expect(nameToken, TokenType.String);
currentAtom.Name = nameToken.Name;
//arguments
Expect(TokenPop(input), TokenType.ParenBegin);
GetArguments(input, currentAtom.Arguments);
var orOrPeriodOrQuestionMark = TokenPop(input);
switch (orOrPeriodOrQuestionMark.Type)
{
case TokenType.Or:
continue;
case TokenType.Period:
if (input.Count > 0)
{
currentTerm = new Term();
output.Terms.Add(currentTerm);
currentTerm.Id = output.Terms.Count;
}
continue;
case TokenType.QuestionMark:
output.Terms.Remove(currentTerm);
output.Goal = currentTerm.Atoms[0];
if (input.Count > 0)
{
currentTerm = new Term();
output.Terms.Add(currentTerm);
currentTerm.Id = output.Terms.Count;
}
continue;
}
throw new Exception("Not the right input: " + orOrPeriodOrQuestionMark.Name);
}
return(output);
}
public RuleData Prune(int rulesLength)
{
var indexComparer = new IndexComparer();
var output = new RuleData();
PruneAddParents(output.Terms, Terms.Last());
output.Terms.Sort(indexComparer);
for (var index = output.Terms.Count - 1; index >= 0; index--)
{
var term = output.Terms[index];
PruneRenumber(output.Terms, term, rulesLength);
}
return(output);
}
public static List <Term> GetNewTerms(Term newestTerm, RuleData rules, List <Term> newTerms)
{
var output = new List <Term>();
for (var i = 0; i < rules.Terms.Count - 1; i++)
{
var combinedTerm = CombineTerms(rules.Terms[i], newestTerm);
if (!combinedTerm.SubMap.Failure &&
!combinedTerm.ExistsInList(rules.Terms) &&
!combinedTerm.ExistsInList(newTerms))
{
output.Add(combinedTerm);
}
}
return(output);
}
public static void Resolve(RuleData rules)
{
Console.WriteLine("Input clauses: ");
rules.Print();
Console.WriteLine("\nQuery:\n " + rules.Goal.Stringify() + "?\n");
var negatedGoal = new Atom(rules.Goal);
negatedGoal.Truthfulness = !negatedGoal.Truthfulness;
var negatedGoalTerm = new Term(negatedGoal)
{
FromGoal = 0
};
var newRules = new RuleData();
newRules.Terms.Add(negatedGoalTerm);
rules.Terms.Add(negatedGoalTerm);
negatedGoalTerm.Id = rules.Terms.Count;
var initialRulesLength = rules.Terms.Count;
var newTerms = GetInitialNewTerms(rules);
while (true)
{
if (newTerms.Count == 0)
{
Console.WriteLine("Result: FALSE. No solution.");
break;
}
newTerms.Sort(termComparer);
var topTerm = newTerms[0];
newTerms.Remove(topTerm);
newRules.Terms.Add(topTerm);
rules.Terms.Add(topTerm);
topTerm.Id = rules.Terms.Count;
if (topTerm.Atoms[0].IsBool && !topTerm.Atoms[0].Truthfulness)
{
Console.WriteLine("Result: TRUE.\n\nProof clauses added:");
newRules = newRules.Prune(initialRulesLength);
newRules.Print();
break;
}
var newestTerms = GetNewTerms(topTerm, rules, newTerms);
newTerms.AddRange(newestTerms);
}
}
public static List <Term> GetInitialNewTerms(RuleData rules)
{
var output = new List <Term>();
for (var i = 0; i < rules.Terms.Count; i++)
{
for (var j = i + 1; j < rules.Terms.Count; j++)
{
var combinedTerm = CombineTerms(rules.Terms[i], rules.Terms[j]);
if (!combinedTerm.SubMap.Failure &&
!combinedTerm.ExistsInList(rules.Terms) &&
!combinedTerm.ExistsInList(output))
{
output.Add(combinedTerm);
}
}
}
return(output);
}
private static bool ResolveGoal(RuleData rules)
{
Resolver.Resolve(rules);
return(true);
}