anchor.diff:  { lib, fetchFromGitHub, python3Packages, file, less, highlight
  -, imagePreviewSupport ? true, w3m ? null}:
  -
  -with lib;
  -
  -assert imagePreviewSupport -> w3m != null;
  +, imagePreviewSupport ? true, w3m }:
   
   python3Packages.buildPythonApplication rec {
  -  name = "ranger-${version}";
  +  pname = "ranger";
     version = "1.9.3";
   
     src = fetchFromGitHub {
  
positive.code:     # give file previews out of the box
      substituteInPlace ranger/config/rc.conf \
        --replace "#set preview_script ~/.config/ranger/scope.sh" "set preview_script $out/share/doc/ranger/config/scope.sh"
    '' + optionalString imagePreviewSupport ''
      substituteInPlace ranger/ext/img_display.py \
        --replace /usr/lib/w3m ${w3m}/libexec/w3m
  
  
negative.code:   meta =  with lib; {
      description = "File manager with minimalistic curses interface";
      homepage = "http://ranger.github.io/";
      license = licenses.gpl3Only;
      platforms = platforms.unix;
      maintainers = with maintainers; [ toonn magnetophon ];
    };
  }
  