[jabajabadu]

That’s right. Our data structures are designed for working with large amounts of compressed text (dynamic FM-Index is one example). They are pretty hard to implement so making a persistent version of such a data structure would require a big time commitment. I imagine that my use case is not that unique and there are many situations where mutable data structures are hard to avoid.

[viebel]

In most languages, there are libraries that provide efficient implementation of persistent data structures.

What languages do you use?

[jabajabadu]

I use C++ and Rust. Unfortunately, there are no persistent versions of the data structures I need available in any language (using dynamic FM-index as an example again). It is just interesting to think about “hybrid” systems where most of the code follows principles of data-oriented programming and some of the code deals with any unavoidable mutability.

[viebel]

I totally agree