Jordan Besly has a nominally provocative post that claims Emacs is not an editor. Of course, it’s only nominally provocative because what he really means is not merely an editor. It is, as we often say at Irreal, a Lisp interpreter specialized for dealing with text that has an editor as one of its built-in applications.
You see that “specialized for dealing with text” frequently in descriptions of Emacs but I think you can make a case that even that’s too restrictive. It’s certainly true in that Emacs has specialized low level (C-based) functions to deal with the efficient display of text but that’s just one facility out of many. I prefer to think of Emacs as a light-weight Lisp machine suitable for many tasks. Of course, things like high speed computation or the manipulation of graphics are not suitable tasks for Emacs but the list of things that are is wider than just those that involve the manipulation of text in some way.
On the other hand, I don’t think it’s true, as Besly claims, that Emacs was designed ab initio “as an extensible environment with text editing as a feature” That claim is trivially false if you take the statement literally. After all, Emacs was originally implemented as a set of macros on top of the TECO editor. But even later, stand-alone versions of Emacs were not conceived as general purpose environments the way Emacs is often thought of today.
Regardless of original intentions, Emacs today certainly embodies the notion of being “an extensible environment with text editing as a feature.” But it’s even more. At least for many of us.