D-1: Isn't Mule upper-compatible with Nemacs/Emacs?

Although Mule is based on GNU Emacs, they are slightly different at the level of emacs lisp. Mule is quite different from Nemacs.

Enami TSUGUTOMO <enami@sys.ptg.sony.co.jp> points out the incompatibility between Mule and Nemacs/Emacs as follows:

• Incompatibility caused by the existence of functions specific to

    each program
  

• Incompatibility caused by the modification of function

    definitions (number of arguments, etc.)
  

• Incompatibility of byte compiled files caused by the difference

    of the internal representation between Mule and Nemacs.  Their
    byte code is compatible, however. (isn't it? :-)
  

• Incompatibility caused by the difference of versions of GNU

    Emacs they are based on.  (only current-column, maybe.)