Guix has packages, and packages have inputs (like dependencies), and you're right in that normally package definitions specify the exact dependencies it the code (they're hardcoded).
Guix package definitions are truely code though, so if you want to generate packages on the fly by using a dependency resolver, you can totally write some code to make that happen.
With respect to inefficiency, what do you mean? It's quite time efficient when building and installing to not have to attempt to resolve dependencies.
Guix package definitions are truely code though, so if you want to generate packages on the fly by using a dependency resolver, you can totally write some code to make that happen.
With respect to inefficiency, what do you mean? It's quite time efficient when building and installing to not have to attempt to resolve dependencies.