private Expression ParseExpr(int precedence)
{
Expression ret = ParseFactor();
while (true) {
Token t = PeekToken();
OperatorToken ot = t as OperatorToken;
if (ot == null) return ret;
int prec = ot.Precedence;
if (prec >= precedence) {
NextToken();
string whiteSpace = _tokenWhiteSpace;
Expression right = ParseExpr(prec + 1);
var start = ret.StartIndex;
ret = new BinaryExpression(GetBinaryOperator(ot), ret, right);
if (_verbatim) {
AddPreceedingWhiteSpace(ret, whiteSpace);
}
ret.SetLoc(start, GetEnd());
} else {
return ret;
}
}
}
// power: atom trailer* ['**' factor]
private Expression ParsePower()
{
Expression ret = ParsePrimary();
ret = AddTrailers(ret);
if (MaybeEat(TokenKind.Power)) {
var start = ret.StartIndex;
string whitespace = _tokenWhiteSpace;
ret = new BinaryExpression(JOperator.Power, ret, ParseFactor());
if (_verbatim) {
AddPreceedingWhiteSpace(ret, whitespace);
}
ret.SetLoc(start, GetEnd());
}
return ret;
}
//comparison: expr (comp_op expr)*
//comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
private Expression ParseComparison()
{
Expression ret = ParseStarExpression();
while (true) {
JOperator op;
string whitespaceBeforeOperator = _lookaheadWhiteSpace;
string secondWhiteSpace = null;
bool isLessThanGreaterThan = false, isIncomplete = false;
switch (PeekToken().Kind) {
case TokenKind.LessThan: NextToken(); op = JOperator.LessThan; break;
case TokenKind.LessThanOrEqual: NextToken(); op = JOperator.LessThanOrEqual; break;
case TokenKind.GreaterThan: NextToken(); op = JOperator.GreaterThan; break;
case TokenKind.GreaterThanOrEqual: NextToken(); op = JOperator.GreaterThanOrEqual; break;
case TokenKind.Equals: NextToken(); op = JOperator.Equal; break;
case TokenKind.NotEquals: NextToken(); op = JOperator.NotEqual; break;
case TokenKind.LessThanGreaterThan: NextToken(); op = JOperator.NotEqual; isLessThanGreaterThan = true; break;
case TokenKind.KeywordIn: NextToken(); op = JOperator.In; break;
case TokenKind.KeywordNot: NextToken(); isIncomplete = !Eat(TokenKind.KeywordIn); secondWhiteSpace = _tokenWhiteSpace; op = JOperator.NotIn; break;
case TokenKind.KeywordIs:
NextToken();
if (MaybeEat(TokenKind.KeywordNot)) {
op = JOperator.IsNot;
secondWhiteSpace = _tokenWhiteSpace;
} else {
op = JOperator.Is;
}
break;
default:
return ret;
}
Expression rhs = ParseComparison();
BinaryExpression be = new BinaryExpression(op, ret, rhs);
if (_verbatim) {
AddPreceedingWhiteSpace(be, whitespaceBeforeOperator);
GetNodeAttributes(be)[NodeAttributes.SecondPreceedingWhiteSpace] = secondWhiteSpace;
if (isLessThanGreaterThan) {
AddVerbatimImage(be, "<>");
}
if (isIncomplete) {
AddErrorIsIncompleteNode(be);
}
}
be.SetLoc(ret.StartIndex, GetEnd());
ret = be;
}
}