Did some more travel today, so I can take things easy tomorrow.
I got started on this late, so it's going to be another quick set of thoughts today.
The missing alternative for Part needs to be a combination of a DynamicFunc[Option[TProgram]] and a vector of ValueAdaptors. It should use some of the code that's currently in the builder decorator, which I'll want to phase out ASAP.
Let's see about writing that class quickly.
Wrote the class, wired it in, no decorators or methods yet...
And, Mypy complained.
Let's fix this quick, and get to bed. Okay, hopefully fixed...
And, actually fixed. I'll work on decorator stuff tomorrow, unless I think of something that needs to happen before that.