/* 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 , # These are needed only because nix's `--arg` command-line logic doesn't work # with unnamed parameters allowed by ... system ? localSystem.system , platform ? localSystem.platform , crossSystem ? null , # 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 isDir = path: pathExists (path + "/."); pathOverlays = try (toString ) ""; homeOverlaysFile = homeDir + "/.config/nixpkgs/overlays.nix"; homeOverlaysDir = homeDir + "/.config/nixpkgs/overlays"; overlays = path: # check if the path is a directory or a file if isDir path then # it's a directory, so the set of overlays from the directory, ordered lexicographically let content = readDir path; in map (n: import (path + ("/" + n))) (builtins.filter (n: builtins.match ".*\\.nix" n != null || pathExists (path + ("/" + n + "/default.nix"))) (attrNames content)) else # it's a file, so the result is the contents of the file itself import path; in if pathOverlays != "" && pathExists pathOverlays then overlays pathOverlays else if pathExists homeOverlaysFile && pathExists homeOverlaysDir then throw '' Nixpkgs overlays can be specified with ${homeOverlaysFile} or ${homeOverlaysDir}, but not both. Please remove one of them and try again. '' else if pathExists homeOverlaysFile then if isDir homeOverlaysFile then throw (homeOverlaysFile + " should be a file") else overlays homeOverlaysFile else if pathExists homeOverlaysDir then if !(isDir homeOverlaysDir) then throw (homeOverlaysDir + " should be a directory") else overlays homeOverlaysDir else [] , crossOverlays ? [] , ... } @ 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 crossSystem crossOverlays; # Fallback: Assume we are building packages on the current (build, in GNU # Autotools parlance) system. localSystem = if builtins.isString localSystem then localSystem else (if args ? localSystem then {} else { system = builtins.currentSystem; }) // localSystem; })