each other, any of which can be redefined in the middle of an editing
session. Almost any part of Emacs can be replaced without making a
separate copy of all of Emacs. Most of the editing commands of Emacs
-are written in Lisp already; the few exceptions could have been written
+are written in Lisp; the few exceptions could have been written
in Lisp but are written in C for efficiency. Although only a programmer
can write an extension, anybody can use it afterward. If you want to
learn Emacs Lisp programming, we recommend the @cite{Introduction to