final: prev:
let lib = final;
in with lib; {

  generators = with final.generators;
    prev.generators // {
      toPreserves = { }@args:
        v:
        let concatItems = lib.strings.concatStringsSep " ";
        in if isAttrs v then
          "{ ${
            concatItems (lib.attrsets.mapAttrsToList
              (key: val: "${key}: ${toPreserves args val}") v)
          } }"
        else if isList v then
          "[ ${concatItems (map (toPreserves args) v)} ]"
        else if isBool v then
          (if v then "#t" else "#f")
        else if isFunction v then
          abort "generators.toPreserves: cannot convert a function to Preserves"
        else if isNull v then
          "null"
        else
          builtins.toJSON v;
    };

}