Good programmers will naturally start to abstract and develop a model that can do more work. But when this happens only in a technical setting, without collaboration with domain experts, the concepts are naive. That shallowness of knowledge produces software that does a basic job but lacks a deep connection to the domain expert’s way of thinking.

For example, there cannot be two parallel flows with mutable access to a value. Nor can there be a flow that borrows a value while there is no flow that owns the value.

A couple of years ago I learned Haskell and to do that I read a book that is universally recommended for beginners and used to be available free online called “Learn you a Haskell for Great Good”.