nixpkgs/pkgs/top-level/impure.nix
Eelco Dolstra 7dacca324d
$NIXPKGS_OVERLAYS -> <nixpkgs-overlays>
The Nix search path is the established mechanism for specifying the
location of Nix expressions, so let's use it instead of adding another
environment variable.
2017-02-01 16:07:54 +01:00

51 lines
1.6 KiB
Nix
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* 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
{ # Fallback: Assume we are building packages for the current (host, in GNU
# Autotools parlance) system.
system ? builtins.currentSystem
, # Fallback: The contents of the configuration file found at $NIXPKGS_CONFIG or
# $HOME/.nixpkgs/config.nix.
config ? let
configFile = getEnv "NIXPKGS_CONFIG";
configFile2 = homeDir + "/.nixpkgs/config.nix";
in
if configFile != "" && pathExists configFile then import configFile
else if homeDir != "" && pathExists configFile2 then import configFile2
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 <nixpkgs-overlays> then <nixpkgs-overlays> else "") "";
dirHome = homeDir + "/.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)
(sort lessThan (attrNames content)));
in
if dirPath != "" then
overlays dirPath
else if dirCheck dirHome then overlays dirHome
else []
, ...
} @ args:
import ./. (args // { inherit system config overlays; })