Nix pass function as dependency to derivation

default.nix

{ pkgs }:

let
  some_function = { arg1, arg2 }: ''
    echo "hello world"
    ${pkgs.nodejs}/bin/node --version
    ${pkgs.vault}/bin/vault --version
  '';

  drv = pkgs.stdenv.mkDerivation {
    name = "test";

    # depends_on = some_function;

    phases = ["build"];
    build = "touch $out";
  };
in
drv // {
  inherit some_function;
}

flake.lock

{
  "nodes": {
    "nixpkgs": {
      "locked": {
        "lastModified": 1636333654,
        "narHash": "sha256-3wh9PtCzcaJQuZrgZ+ygKfhltkDNNqT6zOzGsRbjZEo=",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "e74894146a42ba552ebafa19ab2d1df7ccbc1738",
        "type": "github"
      },
      "original": {
        "id": "nixpkgs",
        "ref": "nixos-21.05",
        "type": "indirect"
      }
    },
    "root": {
      "inputs": {
        "nixpkgs": "nixpkgs"
      }
    }
  },
  "root": "root",
  "version": 7
}

flake.nix

{
  description = "A very basic flake";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-21.05";
  };

  outputs = { self, nixpkgs }:
    let
      pkgs = nixpkgs.legacyPackages.x86_64-linux;
    in
    {
      default = import ./default.nix { inherit pkgs; };
    };
}

run.sh

# build the derivation
nix build .#default

# get the value of some_function with args passed in
nix eval .#default.some_function --apply '(fn: fn { arg1 = "test"; arg2 = "test"; })'
"echo \"hello world\"\n/nix/store/md401gf1prrzlsrrx1gqa5sh6lxjrbih-nodejs-14.18.1/bin/node --version\n/nix/store/sfq1x03vfjd24r88y9xfs4zdc88clbak-vault-1.7.4/bin/vault --version\n"

# How do I get
# /nix/store/md401gf1prrzlsrrx1gqa5sh6lxjrbih-nodejs-14.18.1
# and
# /nix/store/sfq1x03vfjd24r88y9xfs4zdc88clbak-vault-1.7.4
# to build with the derivation implicitly from some_function without passing the arguments?
# As the arguments will only be known at runtime during nix eval like above.