den.aspects Reference

import { Aside } from ‘@astrojs/starlight/components’;

Aspect Attributes

Every aspect is an attribute set with these recognized keys:

Attribute	Type	Description
`nixos`	module	NixOS configuration module
`darwin`	module	nix-darwin configuration module
`homeManager`	module	Home-Manager configuration module
`<class>`	module	Any custom Nix class
`includes`	list	Dependencies on other aspects or functions
`provides`	attrset	Nested sub-aspects
`_`	alias	Shorthand for `provides`
`description`	str	Human-readable description
`__functor`	function	Context-aware behavior

Automatic Aspect Creation

Den creates an aspect for each host, user, and home you declare:

den.hosts.x86_64-linux.igloo.users.tux = { };
# Creates: den.aspects.igloo and den.aspects.tux

Aspects are created with parametric { <class> = {}; } functor matching the entity’s class.

Aspect Resolution

To extract a class module from an aspect:

module = aspect.resolve { class = "nixos"; aspect-chain = []; };

Resolution collects the specified class from the aspect and all transitive includes into a single merged Nix module.

den.aspects (option)

options.den.aspects = lib.mkOption {
  type = aspectsType;
  default = { };
};

Contributions from any module are merged:

den.aspects.igloo.nixos.networking.hostName = "igloo";

# file2.nix
den.aspects.igloo.homeManager.programs.vim.enable = true;

den.provides (batteries)

options.den.provides = lib.mkOption {
  type = lib.types.submodule {
    freeformType = lib.types.attrsOf providerType;
  };
};

Access via den._.name or den.provides.name. See Batteries Reference for all built-in aspects.

den.default

The global dispatcher aspect:

den.default = den.lib.parametric.atLeast { };

All hosts, users, and homes include den.default. Set global configs and shared parametric includes here.

Aliased from den.ctx.default.

Including Aspects

den.aspects.igloo.includes = [
  # another aspect
  den.aspects.gaming

  # nested provides
  den.aspects.tools._.editors

  # static config
  { homeManager.programs.direnv.enable = true; }

  # context function
  ({ host, ... }: { nixos.time.timeZone = "UTC"; })

  # battery
  den._.define-user

  # battery with args
  (den._.user-shell "fish")
  (den._.unfree [ "discord" ])
];

Aspect as Module Argument

den is available as a module argument in all Den modules:

{ den, ... }: {
  den.aspects.foo = den.lib.parametric { ... };
}