[cfv]

If your config files contain anything that could not be expressed as an OS variable, that's a maintenance nightmare right there. Eventually some user somewhere is going to jam entire mini programs in there and then complain when his castle of cards implodes.

Consider, if possible, the chance that if your program needs a subprogram for configuring itself, then maybe a bootstrap event hook or some tap into the bootstrap process like a plugin or something is a better fit for what you are trying to do. Actual managed extension points instead of ad-hoc ones will make your program much more useful in the long run.