request for info on extensible editor

[jeff%aids-unix at sri-unix.UUCP]

From:  Jeff Dean <jeff at aids-unix>

I am interested in getting an editor that can be adapted as a
front end for several different applications.  As a front end,
there are two major capabilities that I think I need.  One is
the ability to write a program (in the editor's langauge) to
massage a part of the text being edited; the other is the
ability to grab a section of the text and send it to another
process.

I know that many versions of Emacs claim to have this power, but
I'd like to find something that is relatively portable.  Does
know of editors (or editor building systems) that satisfy these
criteria?

Thanks...

	Jeff Dean