This addon for Blender 2.8 or later lets you edit a text block in an
external editor, namely Emacs. It uses the “emacsclient” command to
communicate with a currently-running Emacs instance (use the Emacs
command sequence “alt-X server-start” to start your Emacs instance
listening for these connections).

Install this addon into your Blender user area in the usual way. Open
a Blender document containing one or more text blocks. Enable the
addon for that document (you will find it listed in the “Text Editor”
section of your available addons). Go to a Text Editor window. Select
one of your text blocks to edit. In the “Text” menu, you will see a
new option appear: “Edit External”. Select this, and Blender will
appear to freeze. Switch to your Emacs instance, and you should see
the script appear in its window.

When you have finished making changes to the script in Emacs and
saving them in the usual way (“ctrl-X ctrl-S”), press “ctrl-X #” which
will close the file in Emacs and notify the emacsclient command that
editing is complete. At this point, Blender will become responsive
again, and you should see your changes appear in the Text Editor
window.

Lawrence D'Oliveiro <ldo@geek-central.gen.nz>
2019 July 28