Declarative modeling: add find by name functionality

[vik378]

While using declarative modeling I realized referencing objects by uuid is not very human-friendly. In our non-declarative applications (i.e. doc templates) we frequently refer to things by name. I think same thing here would be very helpful:

parent: !find-by-name brew coffee in SA functions

or something like that.

Maybe we could use some extra keywords for scope reduction (so that it knows that we are searching for an LA component or SA function.

[Wuestengecko]

What do you think about this proposal?

- parent: !find
    type: SystemFunction
    name: brew coffee
  create: ...

Except for type (which is special cased to look at the class), this approach would be extensible to allow filtering for every attribute that a model object could have. For example, if you were searching for a Requirement and you know that its combination of chapter_name and foreign_id makes it unique, you could use:

- parent: !find
    type: Requirement
    chapter_name: Chapter 3
    foreign_id: 7
  create: ...

[vik378]

very cool! just to stretch it a bit, would it work if we then also search by human-friendly IDs (property value), like owned_property["DB-ID"]: LFNC-0123 ?

[Wuestengecko]

This could become a bit difficult. I was planning on simply using the good ol' attrgetter, which would give us things like owner.name: ... for free, but that doesn't have the necessary logic / complexity for fully custom attribute names (especially ones that are not guaranteed to be Python identifiers). I'll think about that for a little and try to come up with something.

[Wuestengecko]

Implemented with #387.