Data transformers

[Shadowfiend]

It's not unusual to need to do additional transformation on data before considering it ingestible by a db or other system. A classic example is needing to trim user input before using it for e.g. a name. The proposal here is to allow a data transformer to be attached to a field; in this case, it seems like map might be a good metaphor:

  val nameField = field[String](".selector").map(_.trim) // => a field that trims its values

This also introduces the question of whether field should always default to String and allow using map to do data transformation to another type… For example:

  val thingField = field(".thing-id").map(Thing.findById) // => field[Thing]

I suppose this is might be making fields functors, but I also may not know what I'm talking about…