Abstract domain concepts

[ptal]

Abstract domains have various additional operators depending on their capabilities. For instance, they can be Schedulable or be equipped with projection over vardom. We should find a design in which we do not force an abstract domain to have projection or events, and let Abstract_domain being the minimal interface for satisfiability testing. Abstract transformers could require additional concepts.

I don't really know how to achieve such a design in OCaml with modules and functors. In C++, template and concepts would be used, in Rust it would be traits. Perhaps it requires more advanced functionalities of OCaml such as GADT.