{ mkDerivation, mayo, wrapQtAppsHook, lib }:
let
  step2stl = 
    name: file:
    let
      pname = "${name}.stl";
      extension = lib.last (lib.strings.splitString "." file);
    in
    lib.throwIfNot
      (lib.elem extension ["step" "STEP" "stp"])
      ''Input file have a "${extension}" extension, but valid STEP-file should have one of the following extentions: "step" "STEP" "stp"''
    mkDerivation {
      inherit pname;
      version = "v0";
      src = ./.;
      nativeBuildInputs = [ mayo wrapQtAppsHook ];
      buildPhase = ''${lib.getExe mayo} ${file} -e ${pname}'';
      installPhase = ''
        cp ${pname} $out
        rm ${pname}
      '';
    };
  rlib = { inherit step2stl; };
in
rlib