How to reuse `readFile` `writeFile` program with this module trick?

Assuming `IO.readFile` and `IO.writeFile` is replaced by HTTP requests. I can define `writeFile` and `readFile` in a type class and then implement the effect for HTTP variant, hiding the HTTP client beneath.

Is it just wiring it up in mixins, cabal file?

I think general conclusion is that there's no need for dependency injection, environment objects, or similar tricks if module system is rich enough.

For a long time I questioned why Python needs anything but `async def` or `def` (async should be achievable through module or `yield` usage) and `import` statements, to achieve maximal reuse, given dynamic nature of language and modules. We could ignore all object-oriented features, decorators, replace them with modules. Would be flatter and readable compared to bloated feature set.