There have been quite a few attempts to re-implement (part of) Emacs'
functionalities in languages other than C, like JEmacs, remacs, and lem. And we
are seeing new efforts in EmacsConf 2024: rune 1, schemacs 2,
and the revived Guilemacs 3. (Strictly speaking, Guilemacs is more
a fork than a total rewrite, but anyway.)
However, a complete rewrite of (GNU) Emacs 4 has always seemed like
an insurmountable task, not just because writing editors is hard. This article
aims to look into some of these difficulties and the Emacs designs (that of
course have been exposed in some Emacs Lisp API) that lead to them.
Yes. I think that’s likely why the goal for guilemacs has always been to be able to support elisp and make the transition as smooth as possible, without removing elisp support.
One interesting thing about Guile’s VM (at least last time I checked) is that was designed to support multiple languages, not just Guile Scheme.
Hmm… I wonder if that’s also why there was not a lot of push before, since this would open the doors to js in emacs too, which is a thing RMS did not want.