private ParseErrorType HandleOperator(ParseContext context, IAstNode parent, out bool isUnary) {
ParseErrorType errorType = ParseErrorType.None;
// If operands stack is empty the operator is unary.
// If operator is preceded by another operator,
// it is interpreted as unary.
TokenOperator currentOperator = new TokenOperator(_operands.Count == 0);
currentOperator.Parse(context, null);
isUnary = currentOperator.IsUnary;
IOperator lastOperator = _operators.Peek();
if (isUnary && lastOperator != null && lastOperator.IsUnary) {
// !!!x is treated as !(!(!x)))
// Step back and re-parse as expression
context.Tokens.Position -= 1;
var exp = new Expression(inGroup: false);
if (exp.Parse(context, null)) {
_operands.Push(exp);
return ParseErrorType.None;
}
}
if (currentOperator.Precedence <= lastOperator.Precedence &&
!(currentOperator.OperatorType == lastOperator.OperatorType && currentOperator.Association == Association.Right)) {
// New operator has lower or equal precedence. We need to make a tree from
// the topmost operator and its operand(s). Example: a*b+c. + has lower priority
// and a and b should be on the stack along with * on the operator stack.
// Repeat until there are no more higher precendece operators on the stack.
errorType = this.ProcessHigherPrecendenceOperators(context, currentOperator);
}
if (errorType == ParseErrorType.None) {
_operators.Push(currentOperator);
}
return errorType;
}
private ParseErrorType HandleOperator(ParseContext context, IAstNode parent, out bool isUnary) {
TokenOperator currentOperator = new TokenOperator(firstInExpression: (_operands.Count == 0));
currentOperator.Parse(context, null);
isUnary = currentOperator.IsUnary;
return HandleOperatorPrecedence(context, currentOperator);
}