[mweidner]

One challenge is that the algorithms typically used for collaborative text editing (CRDTs and OT) have strict algebraic requirements for what the edit operations do & how they interact. So even if your server is smart enough to process the "Colour" example in a UX-reasonable way, it's very hard to design a corresponding CRDT/OT, for optimistic client-side edits.

You can work around this by not using CRDTs/OT. E.g., the server processes operations in receipt order, applying whatever UX logic it wants; clients use a rebase/prediction strategy to still allow optimistic edits on top (cf. https://doc.replicache.dev/concepts/how-it-works). Doing this for text editing has some challenges, but they're separate from the CRDT/OT challenges discussed here.

[antics]

Author here! Just chiming in to say this is a very underrated comment which I fully cosign. :)