public static bool evaluateQuantifiedExpression(ParseTreeFOL_Q quantifiedExpression, string[] subwords, List <Assignment> varVals)
{
if (quantifiedExpression.getExpression() != null)
{
return(evaluateLogicalExpression(quantifiedExpression.getExpression(), varVals));
}
bool res = false;
bool endState = false;
//handles the difference between "There Exists" and "For All" quantifiers
if (quantifiedExpression.getFOLQuantifier() == FOLQuantifier.E)
{
endState = true;
}
else
{
res = true;
}
//until we've tried all subwords, or the result proves the quantifier true or false
for (int j = 0; j < subwords.Length && res != endState; j++)
{
List <Assignment> newVarVals = new List <Assignment>();
newVarVals.AddRange(varVals);
Assignment varVal = new Assignment(quantifiedExpression.getQuantifiedVar(), subwords[j]);
newVarVals.Add(varVal);
res = evaluateQuantifiedExpression(quantifiedExpression.getChild(), subwords, newVarVals);
}
return(res);
}
public static string[] GetFreeVars(ParseTreeFOL_Q query)
{
if (query.getExpression() != null)
{
return(GetFreeVars(query.getExpression()));
}
List <string> vars = GetFreeVars(query.getChild()).ToList();
vars.Remove(query.getQuantifiedVar());
return(vars.ToArray());
}
public static List <List <Assignment> > EvaluateQuantifiedExpression(ParseTreeFOL_Q quantifiedExpression, string[] subwords, string body)
{
List <List <Assignment> > solutions;
if (quantifiedExpression.getExpression() == null)
{
solutions = EvaluateQuantifiedExpression(quantifiedExpression.getChild(), subwords, body);
FOLQuantifier quantifier = (FOLQuantifier)quantifiedExpression.getFOLQuantifier();
string variableName = quantifiedExpression.getQuantifiedVar();
if (quantifier == FOLQuantifier.E)
{
if (!solutions.Any(sol => sol.Any(assignment => assignment.GetVariableName() == variableName)))
{
solutions.RemoveAll(a => true);
}
else
{
solutions = FOLSearcher.removeVariable(solutions, variableName);
}
}
else
{
List <List <Assignment> > newSols = new List <List <Assignment> >();
List <List <Assignment> > solsWithoutVar = FOLSearcher.removeVariable(
solutions.ConvertAll(sol => new List <Assignment>(sol)),
variableName);
foreach (List <Assignment> solWithoutVar in solsWithoutVar)
{
bool include = true;
foreach (string word in subwords)
{
List <Assignment> sol = new List <Assignment>(solWithoutVar);
sol.Add(new Assignment(variableName, word));
if (!solutions.Any(solution => CompareSolutions(sol, solution)))
{
include = false;
}
}
if (include)
{
newSols.Add(solWithoutVar);
}
}
solutions = newSols;
}
}
else
{
solutions = EvaluateLogicalExpression(quantifiedExpression.getExpression(), subwords, body);
}
return(solutions);
}