GNU Emacs is an extensible, customizable, free/libre text editor — and more.

At its core is an interpreter for Emacs Lisp, a dialect of the Lisp programming language with extensions to support text editing.
$ apt install emacs$ brew install emacs$ pacman -S emacs$ dnf install emacs$ apk add emacs$ pkg install emacs$ choco install emacs$ scoop install emacsto comment.