public boolean visit(SQLBinaryOpExpr x) {
if (x.getLeft() instanceof SQLBinaryOpExpr) {
SQLBinaryOpExpr left = (SQLBinaryOpExpr) x.getLeft();
if (left.getOperator().priority > x.getOperator().priority) {
print('(');
left.accept(this);
print(')');
} else {
left.accept(this);
}
} else {