Yes, it's polymorphism at compile/build time! But that's not all. C already has this compile time separation where the .h header files represents "compile time interfaces" and .c files the implementation, so that would be the way to go if you use Polylith in C. In the Clojure implementation of the Polylith tool, you don't have to specify the dependencies in a file (similar to a Makefile), instead, this is figured out by the tool. Here we talk about incremental testing, and not incremental builds, and that is not so common out there, and with Polylith it's pretty easy to add support for that, because we already have the dependencies calculated, and small decoupled "snippets of code". The new high-level building blocks together with the standard directory structure, allows us to build tooling around Polylith and more easily reason about our systems. Here are some https://polylith.gitbook.io/polylith/conclusion/production-systems to give you an idea. The decoupling between development and production and the single development experience, is not something you automatically get, regardless of language.