private bool TryOperator()
{
if (!OperatorExpression.IsSymbol(_currentChar))
{
return(false);
}
bool repeat;
string s = _currentChar.ToString();
do
{
string p = _symbolStack.Count == 0 ? string.Empty : _symbolStack.Peek();
repeat = false;
if (_symbolStack.Count == 0)
{
_symbolStack.Push(s);
}
else if (p == "(")
{
_symbolStack.Push(s);
}
else if (Precedence(s) > Precedence(p))
{
_symbolStack.Push(s);
}
else
{
IExpression e = GetExpressionFromSymbol(_symbolStack.Pop());
_expressionQueue.Enqueue(e);
repeat = true;
}
} while (repeat);
return(true);
}