That's the strategy I always take when designing a system. Funny that I never thought about it before, I think most PHP developers will relate to that aswell.

- Procedural single point entrance into the system (network -> public/index.php, cli -> bin/console)

- OOP core for business logic, heavily borrowed (copied) from Java OOP model

- Functional code inside classes/methods whenever possible (callables/closures, array_map/filter/reduce/walk, illuminate/collections, etc.)