All the quirks are little design patterns that look pretty weird at first, not language features themselves. The resource you're looking for is the Nix Pills se

All the quirks are little design patterns that look pretty weird at first, not language features themselves. The resource you're looking for is the Nix Pills series [0]. The LearnXInYMinutes on Nix is also a good overview of the syntax.[1] nix repl is also essential for feeling it out. To answer your question, { config, pkgs, ... }: declares a function that takes an attribute set containing values for "config" and "pkgs". The ellipsis indicates that it's okay to pass extra attributes. Nixos-rebuild calls your function by: with (import <nixpkgs> {}); callPackage ./configuration.nix {} <nixpkgs> is a file containing the set of all symbols (packages are under pkgs, Nix config lives in config, etc.) like a root namespace. callPackage inherits all those symbols and passes them to the function, which is how they got bound. 0. https://nixos.org/nixos/nix-pills/index.html https://nixos.org/nixos/nix-pills/index.html 1. https://learnxinyminutes.com/docs/nix/ https://learnxinyminutes.com/docs/nix/ EDIT: I guess it's also like Git where it's really confusing until a moment of enlightenment where it all makes sense.