public static InputCell CreateCell(NumberBuilder builder)
{
if (builder.IsEmpty())
{
return(null);
}
double number = builder.Build();
builder.Clear();
return(InputCell.Number(number));
}
/// <summary>
/// Counts a result of expression that is represented as a sequence of input cells
/// ordered according the order of the Reverse Polish notation (RPN).
/// </summary>
public double Count(InputCell[] input)
{
var stack = new Stack <InputCell>();
foreach (var cell in input)
{
if (cell.IsNumber())
{
stack.Push(cell);
}
else if (cell.IsOperation())
{
var operandRight = GetOperand(stack);
var operandLeft = GetOperand(stack);
var operation = cell.Expr(operandLeft, operandRight);
var result = InvokeExpession(operation);
stack.Push(InputCell.Number(result));
}
}
return((double)stack.Peek().Value);
}
private static Expression GetOperand(Stack <InputCell> stack)
{
return(stack.PopOrValue(InputCell.Number(0)).Expr.Invoke(null, null));
}