* Prototyping a bit: first class options.  We want the configuration   of NixOS to be specified externally from the main Nix expressions   (since an installation would be hard to maintain if users started   editing the NixOS expressions directory).  But to make that   user-friendly we need:
* Prototyping a bit: first class options.  We want the configuration
  of NixOS to be specified externally from the main Nix expressions
  (since an installation would be hard to maintain if users started
  editing the NixOS expressions directory).  But to make that
  user-friendly we need:

  - Hierarchical options (just like the Nixpkgs configuration).
  - Option descriptions from which documentation can be generated.
  - Validation (e.g., does each option exist? does it have a valid
    value?).
  - The option declarations should be inside the Nix expressions to
    which they are relevant (rather than, say, one big file with option
    declarations).

svn path=/nixu/trunk/; revision=7148

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