What Is Nix on MacOS
Nix is a tool that creates immutable derivations of configurations written in a functional language. This means we don’t depend on our system’s environment at run or build time to create a package, instead we declare all of the dependencies and build in an isolated environment to avoid pollution (a pure environment in nix terms). Because we have declared all of our dependencies, it also means that we can re-build the same exact package again and again (and again!) without worrying about whether we remembered to install libssl-dev before starting to compile or if the new version of a library will break our software because the maintainer make a breaking change in a patch dependency. Plus we can try software out and quickly discard it without worrying about all the extra packages it required.