Functional core + imperative shell can describe any kind of problem. The biggest problem with the approach is that mainstream functional languages put most eff

Functional core + imperative shell can describe any kind of problem. The biggest problem with the approach is that mainstream functional languages put most effort in the functional core rather than the imperative shell modeling. Effect systems (ZIO for Scala, effect-ts) are the only places where fibers allow composing, scheduling and managing "processes" in a functional way.