RFC: Should we migrate from a Model type to a Model concept?

[PhilippMDoerner]

We use inheritance to be able to guarantee that a given Model type will have an id field in norm, but that isn't strictly necessary, is it?

You could just as well make a concept that checks for the existence of an id field.
This would allow for greater flexibility and remove the need for inheritance, because you don't need to actually have an id-field, you need the Syntax for it.

That means you could have models without an id field, but they have procs that allow accessing and setting the field as if they had! Something like this:

type Model = concept model
  model.id is int
  model.id = model.id

type A = ref object
  id: int

type B = ref object
  mongoId: int

proc id(x: B): int = x.mongoId
proc `id=`(x: B, id: int) = x.mongoId = id

proc echoId(x: Model) = echo x.id

let a = A(id: 5)
a.echoId()

let b = B(mongoId: 5)
b.echoId()

In my opinion this would get rid of some of norm's limitations (enforcing the existence of an id column) and thus could be something worthwhile to implement in my eyes.