anchor.diff:          sha256
           version;
         url = "https://bitbucket.org/${owner}/${repo}/get/${rev}.tar.gz";
  -      meta.homepage = "https://bitbucket.org/${owner}/${repo}/";
         extraPostFetch = ''
           # impure file, see https://github.com/NixOS/nixpkgs/pull/12002
           find . -name .hg_archival.txt -delete
  
positive.code:         + "${lib.substring 0 2 repo}/"
          + "${repo}/code.git/"
          + "${repo}-code-${rev}.zip";
        meta.homepage = "http://sourceforge.net/p/${repo}/code";
        preFetch = ''
          echo "Telling sourceforge to generate code tarball..."
          $curl --data "path=&" \
  
negative.code:       inherit name sha256 version;
        url = "https://gitlab.com/${owner}/${repo}/repository/"
          + "archive.tar.gz?ref=${rev}";
      };
  
    fetchFromRepoOrCz =
  