/* Impure default args for `pkgs/top-level/default.nix`. See that file for the meaning of each argument. */ with builtins; let homeDir = builtins.getEnv "HOME"; # Return ‘x’ if it evaluates, or ‘def’ if it throws an exception. try = x: def: let res = tryEval x; in if res.success then res.value else def; in { # We combine legacy `system` and `platform` into `localSystem`, if # `localSystem` was not passed. Strictly speaking, this is pure desugar, but # it is most convient to do so before the impure `localSystem.system` default, # so we do it now. localSystem ? builtins.intersectAttrs { system = null; platform = null; } args , # Fallback: The contents of the configuration file found at $NIXPKGS_CONFIG or # $HOME/.config/nixpkgs/config.nix. config ? let configFile = getEnv "NIXPKGS_CONFIG"; configFile2 = homeDir + "/.config/nixpkgs/config.nix"; configFile3 = homeDir + "/.nixpkgs/config.nix"; # obsolete in if configFile != "" && pathExists configFile then import configFile else if homeDir != "" && pathExists configFile2 then import configFile2 else if homeDir != "" && pathExists configFile3 then import configFile3 else {} , # Overlays are used to extend Nixpkgs collection with additional # collections of packages. These collection of packages are part of the # fix-point made by Nixpkgs. overlays ? let dirPath = try (if pathExists then else "") ""; dirHome = homeDir + "/.config/nixpkgs/overlays"; dirCheck = dir: dir != "" && pathExists (dir + "/."); overlays = dir: let content = readDir dir; in map (n: import (dir + ("/" + n))) (builtins.filter (n: builtins.match ".*\.nix" n != null) (attrNames content)); in if dirPath != "" then overlays dirPath else if dirCheck dirHome then overlays dirHome else [] , ... } @ args: # If `localSystem` was explicitly passed, legacy `system` and `platform` should # not be passed. assert args ? localSystem -> !(args ? system || args ? platform); import ./. (builtins.removeAttrs args [ "system" "platform" ] // { inherit config overlays; # Fallback: Assume we are building packages on the current (build, in GNU # Autotools parlance) system. localSystem = { system = builtins.currentSystem; } // localSystem; })