nixpkgs/lib/default.nix
Eelco Dolstra 0e333688ce Big cleanup of the NixOS module system
The major changes are:

* The evaluation is now driven by the declared options.  In
  particular, this fixes the long-standing problem with lack of
  laziness of disabled option definitions.  Thus, a configuration like

    config = mkIf false {
      environment.systemPackages = throw "bla";
    };

  will now evaluate without throwing an error.  This also improves
  performance since we're not evaluating unused option definitions.

* The implementation of properties is greatly simplified.

* There is a new type constructor "submodule" that replaces
  "optionSet".  Unlike "optionSet", "submodule" gets its option
  declarations as an argument, making it more like "listOf" and other
  type constructors.  A typical use is:

    foo = mkOption {
      type = type.attrsOf (type.submodule (
        { config, ... }:
        { bar = mkOption { ... };
          xyzzy = mkOption { ... };
        }));
    };

  Existing uses of "optionSet" are automatically mapped to
  "submodule".

* Modules are now checked for unsupported attributes: you get an error
  if a module contains an attribute other than "config", "options" or
  "imports".

* The new implementation is faster and uses much less memory.
2013-10-28 22:45:55 +01:00

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1.1 KiB
Nix

let
trivial = import ./trivial.nix;
lists = import ./lists.nix;
strings = import ./strings.nix;
stringsWithDeps = import ./strings-with-deps.nix;
attrsets = import ./attrsets.nix;
sources = import ./sources.nix;
modules = import ./modules.nix;
options = import ./options.nix;
types = import ./types.nix;
meta = import ./meta.nix;
debug = import ./debug.nix;
misc = import ./misc.nix;
maintainers = import ./maintainers.nix;
platforms = import ./platforms.nix;
systems = import ./systems.nix;
customisation = import ./customisation.nix;
licenses = import ./licenses.nix;
in
{ inherit trivial lists strings stringsWithDeps attrsets sources options
modules types meta debug maintainers licenses platforms systems;
# Pull in some builtins not included elsewhere.
inherit (builtins) pathExists readFile;
}
# !!! don't include everything at top-level; perhaps only the most
# commonly used functions.
// trivial // lists // strings // stringsWithDeps // attrsets // sources
// options // types // meta // debug // misc // modules
// systems
// customisation