Please read the vignette.
Or, after installation, the help page:
#> Excerpt Structuring Comments from Your Code File and Set a Table of
#> Contents
#>
#> Description:
#>
#> This is just an R interface to the python package excerpts (<URL:
#> https://pypi.python.org/pypi/excerpts>).
excerptr needs python3, you probably want to have pandoc and a TeX-System such as TeXLive installed. ## Installation
You can install excerptr from gitlab with: