I think you’re right about side effects being the missing ingredient to this discussion, that is leading people to talk past each other. The pattern’s sometimes

I think you’re right about side effects being the missing ingredient to this discussion, that is leading people to talk past each other. The pattern’s sometimes called “imperative shell, functional core”. And I totally agree, this is how you write large code bases without making them unmaintainable. Where to go “linear” vs “modular” is an important design choice, but it’s secondary to the design choice of where to embed state-altering features in your program tree. I think people dislike modular code because they want to have all the “side-effects” visible in one function. Perhaps they’ve only worked in code bases where people have made poor choices in that regard. But if you can guarantee and document things like purity, idempotency, etc, you can blissfully ignore implementation details most of the time (i.e. until performance becomes an issue), which is definitionally what allows a codebase to scale.