public void Append(ConstraintOperator op)
{
op.LeftContext = lastPushed;
if (lastPushed is ConstraintOperator)
{
SetTopOperatorRightContext(op);
}
ReduceOperatorStack(op.LeftPrecedence);
ops.Push(op);
lastPushed = op;
}
public void Push(Token p_token)
{
//push in operator/ operand stack
if (p_token is Operator)
{
//operatorStack.
if (operatorStack.Count == 0 || (operatorStack.Count > 0 && operatorStack.Peek().Priority < (p_token as Operator).Priority))
{
//do remaining operation
operatorStack.Push(p_token as Operator);
}
else
{
List <Token> args = new List <Token>();
for (int i = 0; i < 2; i++) //as these all are binary operators
{
args.Insert(0, LiteralStack.Pop());
}
Token tkn = OperatorStack.Pop().Evalute(args);
LiteralStack.Push(tkn as Literal);
OperatorStack.Push(p_token as Operator);
}
}
else if (p_token is Literal)
{
LiteralStack.Push(p_token as Literal);
}
}
private void BuildNodes(string[] expressionArray)
{
foreach (string item in expressionArray)
{
double tempNumber;
if (double.TryParse(item, out tempNumber))
{
TreeNode <string> number_node = new TreeNode <string> {
Data = tempNumber.ToString()
};
NumberStack.Push(number_node);
}
else
{
TreeNode <string> operator_node = new TreeNode <string> {
Data = item
};
OperatorStack.Push(operator_node);
}
}
}
/// <summary>
/// Performs the Shunting-Yard Algorithm
/// </summary>
public void Shunt()
{
// O(n)
if (!ShuntValid)
{
throw new Exception("Shunt() was called without proper initialisation. Check ShuntValid first!");
}
var working = new List <Symbol>();
foreach (var symbol in Input)
{
if (symbol.GetType() == typeof(Operand))
{
working.Add(symbol); // Add any numbers straight to output
}
else if (symbol.ToString() != "(" && symbol.ToString() != ")")
{ // Operators
var op = (Operator)symbol;
// If function, Push() to stack and continue;
if (op.Op == Operators.Function)
{
OperatorStack.Push(op);
continue;
}
while ((OperatorStack.Count != 0 && // Stack not empty!
(OperatorStack.Peek().Precedence >
op.Precedence || // Top operator has higher precedence than current one
(OperatorStack.Peek().Precedence == op.Precedence && !OperatorStack.Peek().IsRightAssociative))
) && // Top op has equal precendence and is left associative
OperatorStack.Peek().Op != Operators.OpenBracket) // Top op is not opening bracket
{
working.Add(OperatorStack.Pop());
}
OperatorStack.Push(op); // Add operator to stack
}
else
{
switch (symbol.ToString())
{
case "(": // Opening Bracket
OperatorStack.Push((Operator)symbol);
break;
case ")": // Closing Bracket
{
while (OperatorStack.Peek().Op != Operators.OpenBracket)
{
if (OperatorStack.Count == 0)
{
throw new Exception("Ran out of stack while looking for left bracket: input had mismatched brackets.");
}
working.Add(OperatorStack.Pop());
}
if (OperatorStack.Peek().Op == Operators.OpenBracket)
{
OperatorStack.Pop(); // Discard extra brackets
}
break;
}
}
}
}
working.AddRange(OperatorStack); // Final step: pop out entire stack to output
OperatorStack.Clear(); // Apparently AddRange() will Peek() instead of Pop() if the stack only has one element, failing to clear it
Output = working.ToArray();
}