Re: Emacs rewrite in a maintainable language

[Stephen J. Turnbull]

Eli Zaretskii writes:

 > > Rewriting select parts of it in Elisp and/or Scheme seems much more
 > > realistic.
 > 
 > But then it's prudent to ask do the gains justify the effort.

Rewriting "select" parts in Elisp clearly do, at least they have up to
now.  People regularly rewrite C features in Elisp when they run into
the inflexiblity of C (I suppose my estimate is biased since it's
based on [S]XEmacs practice, not Emacs, but [S]XEmacs practice is
somewhat relevant here, and I imagine Emacs practice is not so different).

Rewriting "select" parts in Scheme makes very little sense IMO (unless
you're already running GuileEmacs).  The cost of moving large parts of
core to Scheme not only includes the rewrites themselves (which I
suspect mostly have *not* yet been done in GuileEmacs), but the not-
to-be-underestimated costs of integrating a large branch, as well.
And of course it has a strong (partial) effect of *increasing*
maintenance cost, because the maintainers now have to be familiar with
3 different languages.