Convert NEWS.md to ASCII NEWS

Maybe you know that for some packages in R you can view the NEWS file in the help pane of RStudio:

If you click on it, you can instantly see the NEWS file of a package. This is pretty neat if one of your most used packages was updated (maybe there was even a major version change!) and you want to see what changed.

To make this possible, the maintainer needs to have an ASCII NEWS file when he submits the package to CRAN. While having an ASCII NEWS file was the standard some years ago, nowadays almost everyone uses a markdown written NEWS.md file. This is good because its easier to read in the browser than a plain text file.

Since 1 or 2 years, also CRAN started supporting NEWS.md files. You can find them on the CRAN overview page of any package. To stay with one package in this post, here is the CRAN page for the sperrorest package (I am not sure why the latest news are missing though).

However, the RStudio help page does not render NEWS.md and maintainers would need to maintain two news files if they would like to provide this service. To minimize the effort, I created a small script that only consists of a single sed call (sed is a search/replace function for Unix system).

# 1.'-e' part: Replaces all level 2 headers and appends a ":" at the end of the line
# 2.'-e' part: Indents all bullet points with a whitespace
# 3.'-e' part: Removes all level 2 headers
# 4.'-e' part: For all level 1 headers, add linebreak and 80 hyphens (not strictly required but clean)
# 5.'-e' part: Remove all level 1 headers

sed -e '/^##/ s/$/:/' -e 's/^*/ */' -e 's/^## *//' -e "/^#/a\\--------------------------------------------------------------------------------" -e 's/^# *//' < NEWS.md > NEWS

It will not fit every NEWS.md file but most. It depends on your formatting style (e.g. if you add a colon after each heading or not (I do not)). Just apply it, check the resulting NEWS file and tweak it if needed.

NOTE: You will only see “Package NEWS” entry in the RStudio help pane if the ASCII file is correctly formatted. So if you do not see it after building your package locally (e.g. devtools::document()), something is still wrong. See this file for a correct example.