private List<RexNode> toRex(
RelNode child, FunctionExpression expression) {
RexBuilder rexBuilder = cluster.getRexBuilder();
List<RexNode> list =
Collections.singletonList(
rexBuilder.makeRangeReference(child));
OptiqPrepareImpl.ScalarTranslator translator =
OptiqPrepareImpl.EmptyScalarTranslator
.empty(rexBuilder)
.bind(expression.parameterList, list);
final List<RexNode> rexList = new ArrayList<RexNode>();