In my personal project to learn LISP, I decided to try GNU Guile . It is a Scheme implementation and it is the official extension language of the GNU project . To learn, my first step is to actually use it, and my first minimal toy project, will be a Habit tracker. There are plenty habit trackers around, to make another one, yet this is just mine, done for my personal joy of implementing it in a language I’m trying to learn.