plurid-data-structures-typescript VS RoaringBitmap

Somewhat along these lines, I have formed a concept forcedly called "differentially composable string", or "deposed string", or more precise "poor man's git".

The intended use case is to obtain a compact representation of all the historic text entered into an input field (notes, comments, maybe long-form): all the stages of the text, where a stage is a tuple [add/remove, start_index, text/end_index]. Once you get the stages from the deposed string as JSON, you could transform them however you want then load them into a new deposed string.

You can read more on GitHub: https://github.com/plurid/plurid-data-structures-typescript#... or play around on my note-taking app implementing deposed strings and more: https://denote.plurid.com

I was recently reading about Roaring https://roaringbitmap.org/ which is a highly optimized compressed bitset implementation. I reccomend reading about it if you are interested in this sort of thing. The talk at https://roaringbitmap.org/talks/ is especially good.

However, I would love compressed (not just packed) bitsets too, which is something different to me. I would make it another class with a similar interface, based on something like roaring. It doesn't need to be in the standard, but it would be nice if the API was a such that one could easily swap implementations.

As an aside if you find yourself having to compute them on the fly, know that the Roaring Bitmaps libraries is the way to go [1]. The bitmaps are compressed, and can be streamed directly into SIMD computations (batching XORs and popcnts 256 bits wide!). The Jaccard index is just intersection_len / union_len [2] away

[1] https://roaringbitmap.org/

[2] https://roaringbitmap.readthedocs.io/en/latest/#roaringbitma...

Use a two stage approach, with a bloom/cuckoo filter stored as a https://roaringbitmap.org/ in memory. Then a secondary key/value store on disk (bolt or anything else).

As an aside, if you're dealing with large bit sets, you might also want to evaluate Roaring Bitmaps.

Sidetracking a bit the conversation. What a coincidence that the author (Lemire) is also represented on Today's #1 "Ask HN: What are some cool but obscure data structures you know about?" as he is the main contributor of RoaringBitmap https://github.com/RoaringBitmap/RoaringBitmap and one of the main authors of the data structure.