private bool TryNumber(char c, char l)
{
bool isNumber = NumberExpression.IsNumber(c);
// only negative when last char is group start or symbol
bool isNegative = NumberExpression.IsNegativeSign(c) &&
(l == '\0' || l == '(' || OperatorExpression.IsSymbol(l));
if (!isNumber && !isNegative)
{
return(false);
}
_buffer.Length = 0;
_buffer.Append(c);
char p = (char)_expressionReader.Peek();
while (NumberExpression.IsNumber(p))
{
_buffer.Append((char)_expressionReader.Read());
p = (char)_expressionReader.Peek();
}
double value;
if (!(double.TryParse(_buffer.ToString(), out value)))
{
throw new ParseException(Resources.InvalidNumberFormat + _buffer);
}
NumberExpression expression = new NumberExpression(value);
_expressionQueue.Enqueue(expression);
return(true);
}
private bool TryOperator(char c)
{
if (!OperatorExpression.IsSymbol(c))
{
return(false);
}
bool repeat;
string s = c.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);
}
private IExpression GetExpressionFromSymbol(string p)
{
IExpression e;
if (_expressionCache.ContainsKey(p))
e = _expressionCache[p];
else if (OperatorExpression.IsSymbol(p))
{
e = new OperatorExpression(p);
_expressionCache.Add(p, e);
}
else if (FunctionExpression.IsFunction(p))
{
e = new FunctionExpression(p, false);
_expressionCache.Add(p, e);
}
else if (ConvertExpression.IsConvertExpression(p))
{
e = new ConvertExpression(p);
_expressionCache.Add(p, e);
}
else
throw new ParseException(Resources.InvalidSymbolOnStack + p);
return e;
}