Idea for compiler-checked Application env

Would it be possible for Mix.Config’s config to be a macro which creates accessor functions for the environment variables? E.g.:

# config/config.exs
config :my_app, :key, "value"

…currently enables this kind of access:

"value" = Application.fetch_env!(:my_app, :key)

But instead, I imagine the config macro generates functions at compile time enabling this usage:

"value" = Application.MyApp.key()

The big win is the compile-time checking & LS completion support for MyApp and key. It’s also shorter and more expressive. It doesn’t rely on the programmer remembering to use fetch_env! vs. get_env.

I’m new to macros as well as the Application + Mix.Config system. Would this be possible?

Update: A couple of existing solutions are,

• Skogsra
• @sasajuric’s library described on Twitter