Zed Decoded: Rope & SumTree

Zed Decoded: Rope & SumTree

Text editors like Zed need in-memory data structures that are optimized for handling large strings where text can be inserted or deleted at any point without needing to copy the whole string.

Ropes are a classic, widely used data structure for this.

Zed have their own implementation of ropes in Rust, but it's backed by something even more interesting: a SumTree, described here as a thread-safe, snapshot-friendly, copy-on-write B+ tree where each leaf node contains …

copy data datastructures deleted editors implementation in-memory memory rope rust string strings text