Is there a way to encode function call in JSON so that builtins.fromJSON would be able to parse it? Such as:

pkg = {
  v1 = functionCall { version = "1";};
}

The problem here is that you are using part of users to define another part of users.

This is recursive, and because attrsOf is not lazy it is infinitely recursive.

You can either use types.lazyAttrsOf (which has its own gotchas) or refactor so that you aren't depending on users to define users.foo.

In reply to @quapka4:matrix.org

Is there a way to encode function call in JSON so that builtins.fromJSON would be able to parse it? Such as:

pkg = {
  v1 = functionCall { version = "1";};
}

In reply to @quapka4:matrix.org

Is there a way to encode function call in JSON so that builtins.fromJSON would be able to parse it? Such as:

pkg = {
  v1 = functionCall { version = "1";};
}

Normally you would do this using the callPackage pattern where the various dependencies are inputs to your derivation function.

When you call your derivation using callPackage any arguments will default to pkgs.* if not explicitly passed in.

# A file using your package
{
  foo = pkgs.callPackage ./package.nix { /* explicit args (optional) */ };

  # This overrides a dep
  foobar = pkgs.callPackage ./package.nix {
    inherit some-dep;
  };
}

# package.nix
{
  lib,
  runCommand,
  some-dep,
  other-dep,
}:
runCommand "name" {} ''
  echo "Hello, world!" > "$out"
''

In reply to @infinisil:matrix.org
But the answer to your question of whether it's possible to encode a function in JSON is definitely No :)

Somewhat related, when I output many packages (those auto-generated), can I force nix flake show to show nested outputs? For example:

 # flake.nix
...
  outputs = ...
  {
    packages = {
      pkg = {
        v1 = builder { version = "1"; };
        v2 = builder { version = "2"; };
      };
    };

And then have nix flake show display also pkg.v1, pkg.v2 etc.

In reply to @infinisil:matrix.org
Generally you'll want to have a Nix file that reads and transforms the JSON into what you need, e.g. lib.mapAttrs (name: value: functionCall value) (builtins.fromJSON (builtins.readFile ./foo.json))

In reply to @quapka4:matrix.org

Somewhat related, when I output many packages (those auto-generated), can I force nix flake show to show nested outputs? For example:

 # flake.nix
...
  outputs = ...
  {
    packages = {
      pkg = {
        v1 = builder { version = "1"; };
        v2 = builder { version = "2"; };
      };
    };

And then have nix flake show display also pkg.v1, pkg.v2 etc.

In reply to @quapka4:matrix.org
Also, are there Python bindings to write/read Nix files?

In reply to @ity:itycodes.org
Well, HTML is a markup language while Nix is a programming language. All I can find is https://github.com/nix-community/rnix-parser in Rust, you can probably bind it to Python in some way.