anchor.diff:    src = fetchFromGitHub {
       owner = "tomhrr";
       repo = "dale";
  -    rev = "ecc5ea91efef8a263c7dddd6925983df5b5258b2";
  -    sha256 = "0naly7jsfriiqf68q210ay9ppcvidbwwcxksy5zwy1m17aq5kxaw";
  +    rev = "64e072d0520a134b9ae8038104fa977776b6e0af";
  +    sha256 = "1apvq3v6ra8x0sj8gg9yavqsyxiggh2wnh1zbw2ccpg723bssl4a";
     };
   
     buildInputs = [ cmake libffi llvm_35 ] ++
  
positive.code:       S-expressions for syntax and supports syntactic macros.
      '';
      homepage = "https://github.com/tomhrr/dale";
      license = licenses.mit;
      maintainers = with maintainers; [ amiloradovsky ];
      platforms = platforms.linux;  # fails on Darwin, linking vs. FFI
    };
  }
  
negative.code: { stdenv, fetchFromGitHub, cmake, libffi, llvm_35, perl }:
  
  let version = "20170419";
      doCheck = false;
  in stdenv.mkDerivation {
    name = "dale-${version}";
  