docs(patterns): explain invariants among our orders

[erights]

So far, just porting Agoric/agoric-sdk#4435 to endo. Starting out very stale.

[erights]

@gibson042 what in here is still valuable?

[gibson042]

@gibson042 what in here is still valuable?

I think there's a lot of value, especially in marshal-vs-patterns-level.md. But I would request that it be linked to from the README, and also that we minimize duplicated information (though I don't have a preference for pointing into types.js vs. pointing out from it into Markdown).

[gibson042]

This is super useful, but makes me wonder even more about whether we should incorporate unordered set and/or map into the passStyleOf level as suggested in #1739. It would mean that full ordering could be applied even to unrecognized tagged types, although that ordering might differ from kind-specific ordering.

However, this is certainly not the best place for that discussion.

[erights]

I don't understand this. We do apply full rank orderings to unrecognized tag types, in that rankCompare just does lexicographic ordering of Taggeds, independent of any higher level recognition. Do I misunderstand the question?

[erights]

Re #1739 , from that thread, I think we resolved that we should just use unicode / utf-8 ordering for rankCompare, and therefore keyCompare, and avoid using UTF-16 / CESU-8 ordering for anything at these levels of abstraction. Does that help clarify anything here?

To make that switch, we'll need to ensure that our stores (heap, virtual, and durable) sort their keys in a way that remains consistent with rankCompare. This may conflict with existing durable data, which will be an interesting problem.

Attn @FUDCo @warner

[gibson042]

The content of this file isn't really comprehensible to me. I don't know if there's a good way to present it other than prose.

[erights]

Please identify what you don't understand. But I suspect that anything here not comprehensible to you probably doesn't make sense and should be deleted ;)

[gibson042]

@erights This is ready for you, but you won't be able to submit an actual review since you initially opened it. I think we'll eventually also want to document the specifics of rank order (such as special number values, strings, and using Pareto order to translate subset-like relationships in key comparison) in @endo/marshal.

[erights]

Virtual LGTM, thanks! Awesome to see this!

Now that I've virtually approved, IIUC, you can actually approve and then merge, yes?

(If possible, would be nice to see this merged before ocapn mtg tomorrow)