private static MathValue UnrollMathImpl(MathValue value)
{
var tokens = new List<object>();
Unroll(value, tokens);
var outQueue = new Queue<object>();
var opStack = new Stack<Operator>();
foreach (var t in tokens)
{
if (t is Value)
{
if (t is GroupedValue)
{
var grouped = UnrollMath(((GroupedValue)t).Value);
outQueue.Enqueue(grouped);
continue;
}
if (t is LeftExistsValue)
{
var leftExist = new LeftExistsValue(UnrollMath(((LeftExistsValue)t).IfExists));
outQueue.Enqueue(leftExist);
continue;
}
outQueue.Enqueue((Value)t);
continue;
}
var o1 = (Operator)t;
while (opStack.Count > 0 && Precedence(o1) <= Precedence(opStack.Peek()))
{
var o2 = opStack.Pop();
outQueue.Enqueue(o2);
}
opStack.Push(o1);
}
while (opStack.Count > 0)
{
outQueue.Enqueue(opStack.Pop());
}
return DeRPN(outQueue);
}
internal static Value ParseImpl(ParserStream stream, IPosition forPosition, bool allowSelectorIncludes)
{
Value ret = null;
while (stream.HasMore())
{
var c = stream.Peek();
if (char.IsWhiteSpace(c))
{
stream.AdvancePastWhiteSpace();
continue;
}
if (ret != null)
{
if (c.In('+', '-', '*', '/', '%'))
{
ret = ParseMathValue(c, ret, stream, forPosition);
continue;
}
if (c == '?')
{
stream.Advance(); // skip ?
if (stream.HasMore() && stream.Peek() == '?')
{
if (ret == null)
{
Current.RecordError(ErrorType.Parser, forPosition, "Expected value, found '??'");
throw new StoppedParsingException();
}
stream.Advance(); // skip second ?
var rhs = ParseImpl(stream, forPosition, allowSelectorIncludes);
ret = new MathValue(ret, Operator.Take_Exists, rhs);
continue;
}
ret = new LeftExistsValue(ret);
continue;
}
}
if (char.IsDigit(c) || c == '.' || c == '-')
{
ret = Combine(ret, ParseNumber(stream, forPosition));
continue;
}
if (c == '(')
{
ret = Combine(ret, ParseGroup(stream, forPosition));
continue;
}
if (c.In('\'', '"'))
{
ret = Combine(ret, ParseQuotedString(c, stream, forPosition));
continue;
}
if (c == '#')
{
ret = Combine(ret, ParseHashColor(stream, forPosition));
continue;
}
if (c == '@')
{
ret = Combine(ret, ParseFuncValue(stream, forPosition, allowSelectorIncludes));
continue;
}
ret = Combine(ret, ParseString(stream, forPosition));
}
return ret;
}
