anchor.diff:  
   RUN DEBIAN_FRONTEND=noninteractive R CMD INSTALL \
      jsonlite_1.5.tar.gz \
  -   digest_0.6.12.tar.gz \
  +   digest_0.6.13.tar.gz \
      memoise_1.1.0.tar.gz \
      whisker_0.3-2.tar.gz \
      bitops_1.0-6.tar.gz \
  
positive.code:    htmltools_0.3.6.tar.gz \
     caTools_1.17.1.tar.gz \
     bitops_1.0-6.tar.gz \
     digest_0.6.12.tar.gz \
     mime_0.5.tar.gz
  
  # dependency for R XML library
  
negative.code:    https://mirrors.nics.utk.edu/cran/src/contrib/xml2_1.1.1.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/curl_3.1.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/jsonlite_1.5.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/digest_0.6.13.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/downloader_0.4.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/memoise_1.1.0.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/plyr_1.8.4.tar.gz \
  