public virtual void Visit(ImplicationNode node){}
public override void Visit(ImplicationNode node)
{
throw new NotSupportedException(String.Format(
"Not a CNF or fatal error: '{0}", node.Parent));
}
/// <summary>
/// A method that is called to actually build a tree from a given input. Is called from ProcessStringInput()
/// </summary>
/// <param name="input">input string</param>
/// <param name="root">Node used in recursion for creating a binary tree</param>
/// <exception cref="Exception"></exception>
private void BuildTree(string input, Node root)
{
if (input == string.Empty)
{
return;
}
char first_character = input[0];
if (first_character == '~')
{
NotNode node = new NotNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == '>')
{
ImplicationNode node = new ImplicationNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == '=')
{
BiImplicationNode node = new BiImplicationNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == '&')
{
ConjunctionNode node = new ConjunctionNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == '|')
{
DisjunctionNode node = new DisjunctionNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == '%')
{
NandNode node = new NandNode(input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (Char.IsUpper(first_character) && input[1] == '(')
{
/* predicate case */
/* P(x), Q(x) */
int closingBracketIndex = GetIndexOfClosingBracket(input, 1);
var vars = QuantifierInputHandler.StringStartEndIndex(input, 2, closingBracketIndex - 1).Split(',');
PredicateNode predicate = new PredicateNode(first_character);
List <PropositionNode> propositions = new List <PropositionNode>();
foreach (var variable in vars)
{
propositions.Add(new PropositionNode(variable));
}
predicate.Formulas = propositions;
root.Insert(predicate);
predicate.parent = root;
input = input.Substring(closingBracketIndex + 1);
BuildTree(input, predicate);
}
else if (first_character == '@' || first_character == '!')
{
string quantifierInput = QuantifierInputHandler.ParseOutInputForQuantifiers(input);
QuantifierInputHandler quantifierInputHandler = new QuantifierInputHandler(quantifierInput);
var node = quantifierInputHandler.Create();
node.parent = root;
root.Insert(node);
var newInput = input.Substring(IndexTillWhichStringAreSame(quantifierInput, input) + 1);
BuildTree(newInput, node);
}
else if (first_character == ',')
{
if (root.parent == null)
{
throw new Exception("Error in your input");
}
root = root.parent;
input = input.Substring(1);
BuildTree(input, root);
}
else if (Char.IsLetter(first_character))
{
PropositionNode node = new PropositionNode(first_character.ToString(), input, root);
root.Insert(node);
BuildTree(node.Value, node);
}
else if (first_character == ')')
{
int numberOflevels = CalculateNumberOfLevelsToGoUp(input);
for (int i = 0; i < numberOflevels; i++)
{
if (root.parent != null)
{
root = root.parent;
}
else
{
throw new Exception("Error in string input. Source: class Processor, method BuildTree, else if (')')");
}
}
input = input.Substring(numberOflevels);
BuildTree(input, root);
}
else if (first_character == '(')
{
input = input.Substring(1);
BuildTree(input, root);
}
}
protected virtual IAstTreeNode Xform(ImplicationNode node) { return null; }
public sealed override void Visit(ImplicationNode node) { VisitAndXform(node, Xform(node)); }
protected override IAstTreeNode Xform(ImplicationNode node)
{
return new OrNode(!node.Premise, node.Conclusion);
}
