"Implementation detail" We are in strong disagreement about what constitutes an "implementation detail". But also, you can just use a monad transformer stack

"Implementation detail" We are in strong disagreement about what constitutes an "implementation detail". But also, you can just use a monad transformer stack and add whatever side-effectful operations you want into it, use it as needed. Boom, dependency injection. And more control over what your functions actually do is there when you need it.