Install cl-abnf by entering the following commands in the terminal:
sudo apt update sudo apt install cl-abnf
Common Lisp ABNF parser generator
The generated parser is a regular expression scanner provided by the http://weitz.de/cl-ppcre/ lib, which means that we can't parse recursive grammar definition. One such definition is the ABNF definition as given by the RFC. Fortunately, as you have this lib, you most probably don't need to generate another parser to handle that particular ABNF grammar.