I don't think that you necessarily need lexical locality, rather you need specification. And interfaces are just an easy way to make a specification. The proble

I don't think that you necessarily need lexical locality, rather you need specification. And interfaces are just an easy way to make a specification. The problem with "too much" lexical locality is that now you have to search DEEP into stacks to figure out what really going on. The whole point of specifications is trying to extract the most requirements in the least amount of time. With more "top level" interfaces and tools like DI you can do that, but certainly you can take it too far. A single function, I'd say, is way too far.