Okay, my parser now (correctly) works with objects from #mastodon, #firefish, and #bovine and covers all of AS2, JSON-LD context objects, and a few actor-specific extensions from Mastodon specifically.
I also implemented some (thread safe) caching so as to not annoy myself later.
There's a lot of spit-and-polish still required and a bunch of tests still to write to explore all of the corner cases, but I can call that good for now and move on to something else for a bit.
