Hi Maarten,

If you have the following:

case class TypeTestJsonObject(
  intField: Int,
  stringField: String
) extends JsonObject[TypeTestJsonObject]
{
  def meta = TypeTestJsonObject

object TypeTestJsonObject extends JsonObjectMeta[TypeTestJsonObject]

class ListTestRecord private () extends MongoRecord[ListTestRecord] with
UUIDPk[ListTestRecord] {
  def meta = ListTestRecord

  object mandatoryMongoJsonObjectListField extends
MongoJsonObjectListField(this, TypeTestJsonObject)

object ListTestRecord extends ListTestRecord with
MongoMetaRecord[ListTestRecord]

To add an item to the field:

import net.liftweb.json._
import net.liftweb.json.JsonDSL._

val rec = ListTestRecord.find(...)
val newObj = TypeTestJsonObject(1, "a")

val qry: JValue = ("_id" -> ....)
val upd: JValue = ("$push" -> ("mandatoryMongoJsonObjectListField" ->
newObj.asJObject))

rec.update(qry, upd)

To remove an item:

val upd: JValue = ("$pull" -> ("mandatoryMongoJsonObjectListField" ->
newObj.asJObject))

rec.update(qry, upd)

I've been thinking of adding these functions to the ListFields but haven't
gotten around to it.

Rogue has a much better way of doing this, btw. If you haven't looked into
that, I highly recommend it. Not sure if MongoJsonObjectListField is
supported, though.

Tim