Perhaps the most powerful and widely used tool for literate programming ist Emacs org-mode with the babel extension. I have used it, and it is good!

However, org-mode puts a hurdle to novice users - to practice literate programming, they need to learn a bit of Emacs, which is a task in itself.

I linked the above project because it has two interesting properties:

• One can write the literate document in Markdown. This is not as powerful as org-mode, which is tailored to larger documents, but very accessible.

• One can modify the generated source files directly, and they are automatically read back into the literate document. This makes it much easier to work with existing tools that modify source code.