//>> PrimaryExpr ::= Literal | Number | VariableReference | '(' Expr ')' | FunctionCall
private AstNode ParsePrimaryExpr(AstNode qyInput) {
Debug.Assert(IsPrimaryExpr(this.scanner));
AstNode opnd = null;
switch (this.scanner.Kind) {
case XPathScanner.LexKind.String:
opnd = new Operand(this.scanner.StringValue);
NextLex();
break;
case XPathScanner.LexKind.Number:
opnd = new Operand(this.scanner.NumberValue);
NextLex();
break;
case XPathScanner.LexKind.Dollar:
NextLex();
CheckToken(XPathScanner.LexKind.Name);
opnd = new Variable(this.scanner.Name, this.scanner.Prefix);
NextLex();
break;
case XPathScanner.LexKind.LParens:
NextLex();
opnd = ParseExpresion(qyInput);
if (opnd.TypeOfAst != AstNode.QueryType.ConstantOperand) {
opnd = new Group(opnd);
}
PassToken(XPathScanner.LexKind.RParens);
break;
case XPathScanner.LexKind.Name :
if (this.scanner.CanBeFunction && ! IsNodeType(this.scanner)) {
opnd = ParseMethod(null);
}
break;
}
Debug.Assert(opnd != null, "IsPrimaryExpr() was true. We should recognize this lex.");
return opnd;
}
private static void ComposeOperand(Operand node, StringBuilder expr) {
switch (node.ReturnType) {
case XPathResultType.Number:
expr.Append(node.OperandValue.ToString());
break;
case XPathResultType.String:
expr.Append(s_Apos);
expr.Append(node.OperandValue.ToString());
expr.Append(s_Apos);
break;
case XPathResultType.Boolean:
bool value = (bool) node.OperandValue;
expr.Append(s_Apos);
expr.Append(value ? s_True : s_False);
expr.Append(s_Apos);
break;
default:
Debug.Fail("Unexpected operand type");
break;
}
}
private IQuery ProcessOperand(Operand root) {
return new OperandQuery(root.OperandValue, root.ReturnType);
}