[WIP] Extensible systems using modules

[jaen]

What it says on the tin, basically #135 taken in the direction of using NixOS modules.

Currently stuck at running this:

$ clear; nix flake lock --override-input dream2nix ../../.; nix run .#resolveImpure --show-trace
warning: updating lock file '/home/jaen/Projects/nix/dream2nix/examples/path-example/flake.lock':
• Updated input 'dream2nix':
    'github:nix-community/dream2nix/e5d0e9cdb00695b0b63d1f52ff3b39c0e3035fe3' (2022-05-06)
  → 'git+file:///home/jaen/Projects/nix/dream2nix?ref=extend-subsystems-modules&rev=bf0c5e0bea93afdb4c238a09e27c659c52c679fa' (2022-05-20)
warning: Git tree '/home/jaen/Projects/nix/dream2nix' is dirty
warning: Git tree '/home/jaen/Projects/nix/dream2nix' is dirty
trace: I GOT CALLED AS A PACKAGE! ["builders","callPackageDream","config","discoverers","dlib","fetchers","lib","name","nigga","options","pkgs","specialArgs","subsystem","translators","updaters","utils"]
trace: MAKING MODULE
trace: { extraArgs = <CODE>; translate = <CODE>; translateBin = <CODE>; type = "impure"; version = <CODE>; }
trace: MAKING MODULE
trace: { extraArgs = <CODE>; translate = <CODE>; translateBin = <CODE>; type = "pure"; version = <CODE>; }
trace: { extraArgs = <CODE>; translate = <CODE>; translateBin = <CODE>; type = <CODE>; version = <CODE>; }
error: cannot coerce null to a string

       at /nix/store/9p6y2z7n6zf6v1h5fnz3kyygqmj22lbl-source/src/subsystems/nodejs/translators/impure/package-json/default.nix:54:7:

           53|       cd $WORKDIR
           54|       ${(lib.traceVal specialArgs.translators.nodejs.pure.package-lock).translateBin} $TMPDIR/newJsonInput
             |       ^
           55|     '';

       … while evaluating the attribute 'text' of the derivation 'script.sh'

I suppose this is because I try to loop subsystem elements by putting the elements from evaled module into the evals' specialArgs (yay for cycles) and this is actually not how you should do it. I imagine the solutions would be to instead to have a field with initialised translators in the config and use that, but I haven't had time to work on it since.

[jaen]

Closing in favour of #155