This example is a LuaTeX-based plain TeX project which implements a LuaTeX callback function to show the components of a typeset paragraph. It is designed to accompany a blog post and, for simplicity, it is not a full-blown “parser”—for example, it is not recursive and ignores a number of node types. However, it offers a useful starting point for anyone wishing to explore callbacks in more detail.
This is a document to practice tweaking a class file for the first time, using the example of setting up the possibility of changing the colour theme of the document.
The github to go with it is: https://github.com/latex-ninja/colour-theme-changing-class-tutorial-
It is a reference document for this blogpost.