anchor.diff:      isNsDir = name: type: type == "directory" && hasPrefix "@" name;
       # Names of NPM packages defined in this directory.
       namespaceDirs = lsFilter isNsDir (/. + rootPath);
  -    # Generate the package expression from a package name and .nix path.
  -    toPackage = namespace: name: filepath: let
  -      versionRaw = removeSuffix ".nix" filepath; # Raw version, i.e. "1.2.4"
  -      # Join with package name to make the variable name.
  -      varName = "${replaceDots "-" name}_${replaceDots "-" versionRaw}";
  -      fullPath = "${rootPath}/@${namespace}/${name}/${filepath}";
  -      in
  -      # Return the singleton set which maps that name to the actual expression.
  -      {"${varName}" = callPackage (/. + "${fullPath}") {};};
       in
       # For each namespace directory, each package folder in it, and
       # each .nix file in that, create a package from that and then
  
positive.code:   # Function to remove the first character of a string.
    dropFirstChar = str: concatStrings (tail (stringToCharacters str));
  
    _pkgs = pkgs // {fetchUrlWithHeaders = pkgs.callPackage ./pyFetchurl {};};
  in
  
  rec {
    pkgs = _pkgs;
  
    nodejs = pkgs."nodejs-${replaceDots "_" nodejsVersion}" or (
      throw "The given nodejs version ${nodejsVersion} has not been defined."
    );
  
negative.code:         in deriv;
  
        callPackage = callPackageWith {
          inherit fetchPrivateNpm;
          inherit pkgs nodePackages buildNodePackage brokenPackage;
        };
        nodePackages = joinSets (map (e: e.nodePackages) extensions) //
  