void commaList(SqlWriter writer) {
// The precedence of the comma operator if low but not zero. For
// instance, this ensures parentheses in
// select x, (select * from foo order by z), y from t
for (SqlNode node : list) {
writer.sep(",");
node.unparse(writer, 2, 3);
}
}
void andOrList(SqlWriter writer, SqlKind sepKind) {
SqlBinaryOperator sepOp =
sepKind == SqlKind.AND ? SqlStdOperatorTable.AND : SqlStdOperatorTable.OR;
for (int i = 0; i < list.size(); i++) {
SqlNode node = list.get(i);
writer.sep(sepKind.name(), false);
// The precedence pulling on the LHS of a node is the
// right-precedence of the separator operator, except at the start
// of the list; similarly for the RHS of a node. If the operator
// has left precedence 4 and right precedence 5, the precedences
// in a 3-node list will look as follows:
// 0 <- node1 -> 4 5 <- node2 -> 4 5 <- node3 -> 0
int lprec = (i == 0) ? 0 : sepOp.getRightPrec();
int rprec = (i == (list.size() - 1)) ? 0 : sepOp.getLeftPrec();
node.unparse(writer, lprec, rprec);
}
}
public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
final SqlWriter.Frame frame =
((leftPrec > 0) || (rightPrec > 0)) ? writer.startList("(", ")") : writer.startList("", "");
commaList(writer);
writer.endList(frame);
}