Nix Ecosystem

Only evaluates needed attributes

let expensive = builtins.trace "Computing expensive" (1 + 1); in { a = 1; b = expensive; }.a # Does not compute expensive

Avoid side effects; use derivations for build actions

buildResult = pkgs.stdenv.mkDerivation { ... };

Access patterns

set.attr set."attr-with-dashes"

Recursive attribute set

rec { a = 1; b = a + 1; }

nativeBuildInputs = [ pkgs.cmake ]; buildInputs = [ pkgs.openssl ];

installPhase = '' mkdir -p $out/bin cp mypackage $out/bin/ ''; } Required attributes: pname, version, src Standard phases: unpackPhase, patchPhase, configurePhase, buildPhase, installPhase

Libraries linked at runtime

buildInputs = [ openssl zlib ]; }

config = lib.mkIf config.myModule.enable { # configuration when enabled }; }

inputs = { nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable"; };

outputs = { self, nixpkgs, ... }@inputs: { # output attributes }; }

config = lib.mkIf config.custom.feature.enable { # configuration when enabled }; }

home-manager.useGlobalPkgs = true; home-manager.useUserPackages = true; home-manager.users.username = import ./home.nix; }

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