anchor.diff:     htmltools_0.3.5.tar.gz \
      caTools_1.17.1.tar.gz \
      bitops_1.0-6.tar.gz \
  -   digest_0.6.10.tar.gz \
  +   digest_0.6.12.tar.gz \
      mime_0.5.tar.gz
   
   # dependency for R XML library
  
positive.code:    http://archive.linux.duke.edu/cran/src/contrib/htmltools_0.3.5.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/caTools_1.17.1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/bitops_1.0-6.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/digest_0.6.10.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/stringr_1.2.0.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/markdown_0.7.7.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/highr_0.6.tar.gz \
  
negative.code: 
  RUN rm \
     jsonlite_1.1.tar.gz \
     digest_0.6.12.tar.gz \
     memoise_1.0.0.tar.gz \
     whisker_0.3-2.tar.gz \
     bitops_1.0-6.tar.gz \
  