Write a Commentary

Understand

If you want to understand a book really well, write a commentary on it.

If you want to test whether your favourite programming language can do all the cool things mentioned in some other language’s book, write a commentary on that book, translating the examples into your language. For example, I have a hunch that you can (elegantly) do in Haskell everything you can do with macros in Lisp. So, to test this theory, I can write a commentary on the book “On Lisp” by Paul Graham, which is considered the ultimate guide for Lisp macros.