private Node HandlePositiveFactor()
{
double numberValue;
if (_tokenizer.MatchDouble(out numberValue))
{
return(new ConstantNode(numberValue));
}
string identifier;
if (_tokenizer.MatchIdentifier(out identifier))
{
return(new VariableNode(identifier));
}
if (_tokenizer.Match(TokenType.OpenPar))
{
var e = HandleSuperExpression();
if (!_tokenizer.Match(TokenType.ClosePar))
{
return(new ErrorNode("Expected )."));
}
return(e);
}
return(new ErrorNode("Expected number or (expression)."));
}