struct/lens should define a struct-lens:id transformer

[jackfirth]

Similar to the struct:foo form created by (struct foo ...), this should be a transformer binding holding a list of the lens ids. Used for reflection at compile time. struct-lenses-out should use this.

[AlexKnauth]

Would it be at all possible to use some sort of weird thing with a splicing-local or something to put that information in the main id transformer along with the struct-info?

[jackfirth]

Maybe, but it'd probably be simpler and easier to just keep it separate.