If you have been using Emacs for a while and have been taking advantage of some of its more advanced features, chances are that you have thought of something useful that Emacs doesn’t do. Although Emacs has hundreds of built-in commands, dozens of packages and modes, and so on, everyone eventually runs into some functionality that Emacs doesn’t have. Whatever feature you find missing, you can program using Emacs Lisp.
Before you dive in, however, note that this chapter is not for everyone. It is intended for people who have already become comfortable using Emacs and who have a fair bit of programming experience, though not necessarily with Lisp per se. If you have no such experience, you may want to skip this chapter; if there is something specific you would like Emacs to do, you might try to find a friendly Emacs Lisp hacker to help you write the necessary code. Or, if you’re a little adventurous, you could skim enough to find the file-template example and learn how to install it—it gives you some useful features.
Readers who are building their Lisp skills but don’t necessarily want to read the whole chapter might also want to look for the “Treasure Trove of Examples” section in the middle for a useful tool that can help jumpstart their exploration of the Emacs libraries.
Note that we do not cover Lisp in its entirety in this chapter. That would require another large, dense book. Instead, we cover the basics of the language and other features that ...