Yjs (a widely used text CRDT) describes these sort of opts here: https://blog.kevinjahns.de/are-crdts-suitable-for-shared-edi... For a different tree-based CRDT, I did a head-to-head comparison of implementations that use a node-per-char (Fugue Simple) vs runs (Fugue), with results in Section 5 of this paper: https://arxiv.org/abs/2305.00583
https://josephg.com/blog/crdts-go-brrr/
"We can use a flat array to store everything, rather than an unbalanced tree. This makes everything smaller and faster for the computer to process."
I still stand by what I wrote in that blog post. Using lists rather than trees is still a good approach. And it’s super simple to implement too. You can have a working crdt in a few dozen lines of code.
I’m happy to answer questions if anyone is curious about this stuff. Ive been working to implement and optimise CRDTs for years at this point. Increasingly I’m seeing it as a solved problem.
In particular, I've invented a new simple text format for this which I call Recursive teXt (RX) [1]. The idea is to just develop a CRDT for RX. RX is naturally structured as a tree, and it seems to make sense to model a document as an A of blocks, a block as an A of lines and blocks, and a line as an A of characters. Here "A of" stands for some sort of CRDT array based on inserting via predecessor (and successor?). Each A-object (document, block, line) is referenced by its own id and stored in a purely functional tree (similar to how Redux would do it [3], and I think Automerge does it similarly).
Would be great to get your opinion on this design choice, maybe you see some obvious (or not so obvious) problems with it. One problem seems to be one that Kleppmann points out in [2, end of section 4], when you press enter in the middle of a line, so that a line is split into two lines, you have to deal with that in a special way. Similarly with splitting/joining blocks.
[1] https://practal.com/recursivetext/
[2] https://martin.kleppmann.com/papers/list-move-papoc20.pdf
[3] https://redux.js.org/usage/structuring-reducers/normalizing-...
Quick note: on mobile, the text inputs for the clients is forcing all the text to be very tiny, and you need to manually zoom in to read it.
Why bother with CRDTs if you’re doing server-side synchronization?
MMORPGs can handle synchronizing thousands of users without problem.
(tl;Dr: time-series event storage via a LWW-element-set)
