nix-super/tests/lang/eval-okay-search-path.nix
Eelco Dolstra 62a6eeb1f3 Make the Nix search path declarative
Nix search path lookups like <nixpkgs> are now desugared to ‘findFile
nixPath <nixpkgs>’, where ‘findFile’ is a new primop. Thus you can
override the search path simply by saying

  let
    nixPath = [ { prefix = "nixpkgs"; path = "/my-nixpkgs"; } ];
  in ... <nixpkgs> ...

In conjunction with ‘scopedImport’ (commit
c273c15cb1), the Nix search path can be
propagated across imports, e.g.

  let

    overrides = {
      nixPath = [ ... ] ++ builtins.nixPath;
      import = fn: scopedImport overrides fn;
      scopedImport = attrs: fn: scopedImport (overrides // attrs) fn;
      builtins = builtins // overrides;
    };

  in scopedImport overrides ./nixos
2014-05-26 17:02:22 +02:00

11 lines
389 B
Nix

with import ./lib.nix;
with builtins;
assert pathExists <nix/buildenv.nix>;
assert length nixPath == 6;
assert length (filter (x: x.prefix == "nix") nixPath) == 1;
assert length (filter (x: baseNameOf x.path == "dir4") nixPath) == 1;
import <a.nix> + import <b.nix> + import <c.nix> + import <dir5/c.nix>
+ (let nixPath = [ { path = ./dir1; } { path = ./dir2; } ]; in import <a.nix>)