public TupleExpr visit(ASTSelectQuery node, Object data)
throws VisitorException
{
TupleExpr tupleExpr;
ASTQueryBody queryBodyNode = node.getQueryBody();
if (queryBodyNode != null) {
// Build tuple expression for query body
tupleExpr = (TupleExpr)queryBodyNode.jjtAccept(this, null);
}
else {
tupleExpr = new SingletonSet();
}