Q: support for merge operators

[mindreframer]

Hi @Elzor ,

i have been playing with ex_rock and it's really great! I have one usecase, that is currently not covered by rocker/ex_rock: support for merge operators.

I want to maintain a list of items as value and right now i would be required to read the whole list, append an item and serialize and write it back... which breaks down pretty quickly with larger lists.

I saw this example:

• https://github.com/rust-rocksdb/rust-rocksdb/blob/master/src/merge_operator.rs

Here is a talk with some deeper explanation: https://youtu.be/LPAm2dP69pE?t=2235 (this exact moment). Now, I'm not sure it is possible to expose this feature to Elixir... Defining and registering a custom merge operator.

Do you have any idea if it would be possible? I'm building my own indexes in Rocksdb and this feature would really allow proper index management.

Best, Roman