Some time ago, I started to develop programs using tiny, super general, higher-order functions and I began to borrow a little from functional programming. I noticed interesting things about these new programs. They called for special language features that I had until then heard of but never really needed. I'm referring to language features like support for first-class functions, closures, and lexical binding. The programs I produced were smaller and easier to debug than programs written in a traditional procedural style.

What is Emacs?

Emacs is not just an editor. It's an editor construction kit that comes with a half-finished editor. And that's one of the features that makes it by far the best text editor in the world. The other feature is that you program it in Lisp. O.K., so Elisp (Emacs's Lisp) is an antiquated dynamically scoped Lisp, but it's still a real Lisp with Lisp macros and all.