{stdenv, fetchurl, perl, ghc}: stdenv.mkDerivation { name = "happy-1.14"; src = fetchurl { url = http://www.haskell.org/happy/dist/1.14/happy-1.14-src.tar.gz; md5 = "501b5b63533b2e2838de18085e8c4492"; }; buildInputs = [ghc perl]; }