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: 
  
    /* This function recursively removes all derivation attributes from
       `x' except for the `name' attribute.  This is to make the
       generation of `options.xml' much more efficient: the XML
       representation of derivations is very large (on the order of
       megabytes) and is not actually used by the manual generator. */
    scrubOptionValue = x:
      if isDerivation x then
        { type = "derivation"; drvPath = x.name; outPath = x.name; name = x.name; }
  
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;
  