You can use any CRDT with Braid. Many of them prune history. In fact, we have developed the first pruning p2p text sync algorithm: braid.org/antimatter
Indeed, text sync requires old history to merge with old edits. However, Braid does not force you to hold everything. Peers can implement their own policies for deciding who to sync with. They can also ask each other for modules of old history they've forgotten if they realize they need it to merge something. This is made possible with the new Time Machine architecture that we are writing up.
This architecture also allows you to sync at multiple time resolutions -- realtime, fine grained, or slower, course grained -- within the same system. Different peers can hold and share at different resolutions. And they can all guarantee consistency with each other in the end. See the recent simpleton algorithm work for an example.
Indeed, text sync requires old history to merge with old edits. However, Braid does not force you to hold everything. Peers can implement their own policies for deciding who to sync with. They can also ask each other for modules of old history they've forgotten if they realize they need it to merge something. This is made possible with the new Time Machine architecture that we are writing up.
This architecture also allows you to sync at multiple time resolutions -- realtime, fine grained, or slower, course grained -- within the same system. Different peers can hold and share at different resolutions. And they can all guarantee consistency with each other in the end. See the recent simpleton algorithm work for an example.