anchor.diff:      else x;
   
   
  -  /* For use in the ‘example’ option attribute.  It causes the given
  -     text to be included verbatim in documentation.  This is necessary
  -     for example values that are not simple values, e.g.,
  -     functions. */
  +  /* For use in the `example` option attribute. It causes the given
  +     text to be included verbatim in documentation. This is necessary
  +     for example values that are not simple values, e.g., functions.
  +  */
     literalExample = text: { _type = "literalExample"; inherit text; };
   
  -
  -  /* Helper functions. */
  -
  -  # Convert an option, described as a list of the option parts in to a
  -  # safe, human readable version. ie:
  -  #
  -  # (showOption ["foo" "bar" "baz"]) == "foo.bar.baz"
  -  # (showOption ["foo" "bar.baz" "tux"]) == "foo.\"bar.baz\".tux"
  +  # Helper functions.
  +
  +  /* Convert an option, described as a list of the option parts in to a
  +     safe, human readable version.
  +
  +     Example:
  +       (showOption ["foo" "bar" "baz"]) == "foo.bar.baz"
  +       (showOption ["foo" "bar.baz" "tux"]) == "foo.\"bar.baz\".tux"
  +  */
     showOption = parts: let
       escapeOptionPart = part:
         let
  
positive.code:       else
          val) (head defs).value defs;
  
    # Extracts values of all "value" keys of the given list
    #
    # Examples:
    #   getValues [ { value = 1; } { value = 2; } ] // => [ 1 2 ]
    #   getValues [ ]                               // => [ ]
    getValues = map (x: x.value);
  
    # Extracts values of all "file" keys of the given list
    #
    # Examples:
    #   getFiles [ { file = "file1"; } { file = "file2"; } ] // => [ "file1" "file2" ]
    #   getFiles [ ]                                         // => [ ]
    getFiles = map (x: x.file);
  
    # Generate documentation template from the list of option declaration like
  
negative.code: 
  rec {
  
    /* Returns true when the given argument is an option
  
       Type: isOption :: a -> bool
  
       Example:
         isOption 1             // => false
         isOption (mkOption {}) // => true
    */
    isOption = lib.isType "option";
  
    /* Creates an Option attribute set. mkOption accepts an attribute set with the following keys:
  
       All keys default to `null` when not given.
  
       Example:
         mkOption { }  // => { _type = "option"; }
         mkOption { defaultText = "foo"; } // => { _type = "option"; defaultText = "foo"; }
    */
    mkOption =
      {
      # Default value used when no definition is given in the configuration.
      default ? null,
      # Textual representation of the default, for the manual.
      defaultText ? null,
      # Example value used in the manual.
      example ? null,
      # String describing the option.
      description ? null,
      # Related packages used in the manual (see `genRelatedPackages` in ../nixos/doc/manual/default.nix).
      relatedPackages ? null,
      # Option type, providing type-checking and value merging.
      type ? null,
      # Function that converts the option value to something else.
      apply ? null,
      # Whether the option is for NixOS developers only.
      internal ? null,
      # Whether the option shows up in the manual.
      visible ? null,
      # Whether the option can be set only once
      readOnly ? null,
      # Obsolete, used by types.optionSet.
      options ? null
      } @ attrs:
      attrs // { _type = "option"; };
  
    /* Creates an Option attribute set for a boolean value option i.e an
       option to be toggled on or off:
  
       Example:
         mkEnableOption "foo"
         => { _type = "option"; default = false; description = "Whether to enable foo."; example = true; type = { ... }; }
    */
    mkEnableOption =
      # Name for the created option
      name: mkOption {
      default = false;
      example = true;
      description = "Whether to enable ${name}.";
      type = lib.types.bool;
    };
  
    /* This option accepts anything, but it does not produce any result.
  
       This is useful for sharing a module across different module sets
       without having to implement similar features as long as the
       values of the options are not accessed. */
    mkSinkUndeclaredOptions = attrs: mkOption ({
      internal = true;
      visible = false;
  