Joe Hellerstein
Joe Hellerstein
@joehellerstein.bsky.social
Computer things @Berkeley and music things elsewhere.
posted today!

BTW I peeked at the automerge Rust? Collaborative editing is an example where one probably *has* to resort to unsafe behavior (you're the expert there!) so I'm mostly advocating for more encapsulation/comments in that case.

jhellerstein.github.io/blog/crdt-do...
CRDTs #3: Do Not Read!
Ever used a CRDT, thought you were safe, and—boom—you bought a Ferrari you didn't mean to? It could happen to you! The truth is that CRDTs are dangerous to…
jhellerstein.github.io
May 28, 2025 at 8:40 PM
Really early and well seen, definitely influenced me and my team! Hats off.
May 25, 2025 at 6:51 PM
Depends what you want the “set of lists” semantics to mean. I’d think you likely want a 2P-map lattice of RGAs (2P-map would be like a 2P-set but with a lattice value associated with each unique item in adds). If you want more detail please comment in the blog so it’s easier for others to find it.
May 25, 2025 at 6:50 PM
There are simple and helpful composites that can be written generically and reused safely. E.g. lattice pairs (free or lexical) and Map lattices. Helps to have a language with good support for generics (parameterized types).
May 25, 2025 at 6:46 PM
April 16, 2025 at 5:29 PM
GPT4o did better:
February 13, 2025 at 7:19 PM
The question: "what are examples of commutative functions that are not associative?"

GPT4 was funny, thinking aloud and then proving itself wrong:
February 13, 2025 at 7:18 PM
I think “getting all of your coordination under one roof” (or behind a unified api or something) is the message I’m hearing from you. Don’t know if that helps?
January 28, 2025 at 5:33 AM
A muddled post at best. A sequential log *is* a point of coordination. It doesn't avoid coordination as claimed, it just centralizes it in 1 service (and arguably encourages overuse). Coordination avoidance is orthogonal: discover when global ordering is not needed. Ie avoidance avoids the log!
January 24, 2025 at 6:06 PM
Fickle faculty followup follies
January 8, 2025 at 12:22 AM