Nanoc is written in Ruby and does not hide its Ruby roots:

• Nanoc requires Ruby to be installed and kept up to date. It is also recommended to install Bundler (which does not come with Ruby by default) to manage optional dependencies.

• Nanoc requires knowledge of Ruby to create anything but the most trivial of sites. The heart of a Nanoc site is arguably the Rules file, which is written in Ruby.

These two points combined makes Nanoc not an appealing choice for people who do not want to manage a Ruby installation (with dependencies such as Bundler), and/or do not want to learn and maintain their knowledge of Ruby as a programming language.

Nanoc was written in Ruby’s heyday, and Nanoc’s initial release followed a little after Rails’ 1.0 release. The attention that Rails and Ruby got from the web development community made Ruby a great choice at the time.

Replacing Ruby with anything else is a ton of work (not just the rewrite but also providing a smooth migration path). Languages like Go and Rust might have been a good choice at the beginning of the development of Nanoc — if they had existed.