// implementation of ExpressionComparabilityWrapper that transforms the RHS key to match the row key
// structure of the LHS column. This is essentially optimizing out the expressions on the LHS by
// applying the appropriate transformations to the RHS (through the KeyPart#getKeyRange method).
// For example, with WHERE (invert(a),b) < ('abc',5), the 'abc' would be inverted by going through the
// childPart.getKeyRange defined for the invert function.
rhs = RowValueConstructorExpression.coerce(rvc, rhs, new ExpressionComparabilityWrapper() {
@Override
public Expression wrap(final Expression lhs, final Expression rhs) {
final KeyPart childPart = keySlotsIterator.next().iterator().next().getKeyPart();
// TODO: DelegateExpression