Use nix + direnv to bootstrap book environment

[marcoziti]

Use Nix to bootstrap book rendering environment

Benefit:

• Reproducible and isolated environment without affecting polluting the operating system environment
• Support Windows, Linux and MacOS
• Tools to support producing html, e-pub, pdf format

How-to:

• Install Nix, see for more detail
• Install direnv, see for more detail
• run direnv allow in root directory to start bootstraping, and moment later, enjoy

[pedropark99]

Uhmm, I'm curious, why using direnv in this instance? Because, in theory, all dependencies necessary to compile the book can be installed from Nix.

[marcoziti]

You are right that Nix would meet the need of reproducible environment by running nix-shell. This combination (direnv + Nix) provides a seamless, automated, and consistent way to bootstrap/unload project environment when switching between different projects (folders).

[pedropark99]

I will close this PR, because:

• we just added a Nix Flake file to the project by @bengtfrost .
• also, direnv is (in my personal understanding) unnecessary in this project.

Nonetheless, thank you for openning the discussion on "Let's have Nix on this project" !