anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "racket";
  -  version = "5.2.1";
  +  version = "5.3.3";
     name = "${pname}-${version}";
   
     src = fetchurl {
       url = "http://download.racket-lang.org/installers/${version}/${pname}/${name}-src-unix.tgz";
  -    sha256 = "1v5kvp7vfi4a4bn08jlaga441amlfxpjw9dm6vc1fazwzd72m539";
  +    sha256 = "1qp0fmsh4dkxvlj35xnwdcf4m97jcf927cwhnckjicqx1lfa0wj7";
     };
   
     # Various racket executables do run-time searches for these.
  
positive.code:   '';
  
    meta = {
      description = "Racket (formerly called PLT Scheme) is a programming language derived from Scheme.";
      longDescription = ''
        Racket (formerly called PLT Scheme) is a programming language derived
        from Scheme. The Racket project has four primary components: the
  
negative.code:     '';
  
      homepage = http://racket-lang.org/;
      license = stdenv.lib.licenses.lgpl2Plus; # and licenses of contained libraries
      maintainers = [ stdenv.lib.maintainers.kkallio ];
      platforms = stdenv.lib.platforms.linux;
    };
  