TerminusDB is written in Prolog, pretty cool. See eg <a href="https://github.com/terminusdb/terminusdb/blob/main/src/core/api.pl" rel="nofollow">https://github.com/terminusdb/terminusdb/blob/main/src/core/...</a>
This is my account of how we took the idea of succinct data structures, and added mutability, thereby getting something which allows for git-like functionality, but also fast query and compact memory footprint.