/// <summary>
/// 要素登録
/// </summary>
/// <param name="pItem">要素</param>
/// <remarks>
/// CalculatorItemBaseクラスおよび派生クラスを登録します。
/// 登録する順番は数式に準じます。
/// </remarks>
public void Entry(CalculatorItemBase pItem)
{
if (pItem is CalculatorValueBase)
{
this.mStackValue.Push((CalculatorValue)pItem);
return;
}
CalculatorOperatorBase opeThis = (CalculatorOperatorBase)pItem;
// (
if (opeThis.OperatorType == CalculatorOperatorBase.EnumOperatorType.Open)
{
this.mStackOperator.Push(opeThis);
return;
}
// )
if (opeThis.OperatorType == CalculatorOperatorBase.EnumOperatorType.Close)
{
while (true)
{
CalculatorOperatorBase ope = this.mStackOperator.Pop();
ope.Calculation(this.mStackValue);
if (ope.OperatorType == CalculatorOperatorBase.EnumOperatorType.Open)
{
break;
}
}
return;
}
if (mStackOperator.Count == 0)
{
this.mStackOperator.Push(opeThis);
return;
}
CalculatorOperatorBase opeBefore = mStackOperator.Peek();
int priority = opeBefore.ComparePriority(opeThis);
if (priority < 0)
{
this.mStackOperator.Push(opeThis);
return;
}
opeBefore.Calculation(this.mStackValue);
mStackOperator.Pop();
this.mStackOperator.Push(opeThis);
}
/// <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();
}