internal void AppendNumber(double tokenVal)
{
TreeNode child = new TreeNode();
child.type = nodeType.number;
child.val = new Value(tokenVal, Restrictions.none);
child.name = tokenVal.ToString();
child.numericalEvaluation = true;
children.Insert(0, child);
//clear the static visualization output string:
output = string.Empty;
}
/// <summary>
/// Take each token string from the list of postfixedtokens and build a parse tree
/// with each node evaluated when possible.
/// </summary>
internal void AppendOperator(string tokenString)
{
//Will always take an operation and append two numbers as children
//This is necessitated by the postfixed token construction
const int numberOfChildLeafs = 2; //For primitive operations, this number is 2. For functions its variable
TreeNode child = new TreeNode();
child.type = nodeType.operation;
child.name = tokenString;
TreeNode[] childLeafNodes = new TreeNode[numberOfChildLeafs];
for (int i = 0; i < numberOfChildLeafs; i++) {
childLeafNodes[i] = children[0];
children.RemoveAt(0);
child.children.Insert(0, childLeafNodes[i]);
}
if (childLeafNodes.All(i => i.numericalEvaluation)) {
child.numericalEvaluation = true;
child.val = new Value(
postFixedOperatorEvaluator(childLeafNodes.Select(i => i.val.deciValue).ToList(),
tokenString),
new Factors(childLeafNodes.Select(i => i.val.factors).ToList()),
Restrictions.none);
}
flattenTieredAddOrMult(child);
children.Insert(0, child);
}
internal void AppendVariable(string p)
{
if (p == "ans") {
TreeNode child = new TreeNode();
child.type = nodeType.number;
double tokenVal = OutputLog.returnValues.Last().deciValue;
child.val = new Value(tokenVal, Restrictions.none);
child.name = tokenVal.ToString();
child.numericalEvaluation = true;
children.Insert(0, child);
//clear the static visualization output string:
output = string.Empty;
} else
throw new Exception("unknown variable");
}
/// <summary>
/// For commutative operations its possible to have one operation node with many children
/// instead of tiered iterations of the operation. This method is to change from the
/// latter to the former.</summary>
private void flattenTieredAddOrMult(TreeNode node)
{
TreeNode adjustedNode = new TreeNode();
switch (node.name) {
case "+":
for (int i = 0; i < node.children.Count(); i++) {
if (node.children[i].name == "+") {
adjustedNode = node.children[i];
node.children.RemoveAt(i);
foreach (TreeNode t in adjustedNode.children) {
node.children.Add(t);
}
}
}
break;
case "*":
List<int> commonFactors = new List<int>();
for(int i=0; i < node.children.Count(); i++){
if (node.children[i].name == "*") {
adjustedNode = node.children[i];
node.children.RemoveAt(i);
foreach (TreeNode t in adjustedNode.children) {
node.children.Add(t);
}
}
}
if (this.numericalEvaluation) {
//this means that all the children are numbers and we have evaluated
//TODO: take out the common factors from val.factors
//Make it work by using exponents
}
break;
}
}
public TreeNode BuildParseTree() {
TreeNode parseTree = new TreeNode();
foreach (Token token in tokens) {
switch (token.TokenType) {
case TokenType.number:
parseTree.AppendNumber(token.TokenNumValue);
break;
case TokenType.arithmeticOp:
parseTree.AppendOperator(token.TokenString);
break;
case TokenType.variable:
parseTree.AppendVariable(token.TokenString);
break;
default:
throw new Exception("This token type cannot be appended to the parse tree");
}
}
//The root node is always redundant by construction
return parseTree.children.First();
}