Protesilaos Stavrou

'Emacs Lisp Elements' book version 2

I just published a new version of my Emacs Lisp Elements. Below are the release notes.

Emacs Lisp Elements version 2.0.0

This is a major rewrite of the book. It has almost doubled in word count. I explain more concepts and do it from the ground up. Every single one of the original chapters is redone. They now contain insights into functionality they would previously hint at, such as how ‘apply’ works in practice, what a non-local exit is, and how recursive editing is done.

I have also added several new chapters. As before, chapters have cross references, so you will benefit from revisiting relevant topics.

If you read the Info version of the book, note that all functions, variables, and concepts have their own indices. Use those as another means of navigating the book’s contents. To read the Info version, clone the Git repository, use ‘M-x dired’ to open its directory, move the cursor over the file ‘elispelem.info’ and do ‘M-x dired-info’.

What follows is a brief description of the new chapters.

  • Basics of how Lisp works: A step-by-step guide to how Lisp code is written and how Emacs can tell apart a function call from a variable even when those have the same symbol.

  • Introspecting Emacs: Explores some of the ways we can learn about the present state of Emacs. The idea is to develop the habit of asking Emacs about itself before we do an online search. This way we can also expose ourselves to Elisp code, which helps us become better programmers.

  • Add metadata to symbols: An explanation of how we can associate symbols with data that can then be used for further computations.

  • What are major and minor modes: Presents the basics of modes in Emacs. It explains what major and minor modes have in common and how they differ, while also discussing relevant concepts of precedence.

  • Hooks and the advice mechanism: Explains what are hooks and how they work. It also covers the powerful advice mechanism, as some uses of it as similar to what hooks are supposed to do.

  • Autoloading symbols: Shows how Emacs manages to “lazy load” code when it needs to. This is especially helpful for package developers.

  • Emacs as a computing environment: A more general view of Emacs that helps us appreciate the value of Emacs Lisp. The more time we put into learning this programming language, the better we will get at controlling large parts of our computing life through Emacs.

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