On Fri, Oct 7, 2016 at 12:20 PM Søren Pilgård <fiskomaten@gmail.com> wrote:

> First of all we need to decide what it really is that is wanted here.
> Is it just the underlying lisp engine or what exactly?
>
> Is it basically replacing the C parts with Common lisp code?
> That does not seem to gain much.
>
> Is it to discard Emacs lisp entirely (maybe in a longer process) and
> replace it with Common lisp
> This would discard decades of code and mountains of configurations for
> what gain exactly?
>
> Or is the goal to find a mapping of Emacs lisp to Common lisp.
> So we can build up the core concepts in common lisp and then map
> whatever Emacs code down into Common lisp?
> Then people will ask next if in the future can code for Emacs directly
> in Common lisp and not just in "legacy" Emacs lisp.
>
> Keeping this distinction in mind is important, especially when talking
> to people outside the development group.
> A lot of people had very different ideas and interpretations of what
> the Emacs-guile project intented to do and did.
>
> Be aware that Emacs lisp is not Common lisp and such a mapping does
> have some pitfalls, especially around dynamic scoping and buffer local
> variables.
> I remember some blogposts about this (from 2012)
> http://tromey.com/blog/?p=709 http://tromey.com/blog/?p=751
> http://tromey.com/blog/?p=778
>
> Personally I could fear that this mapping will insert certain
> restrictions of what can
> and can't be done in Common lisp code against Emacs, especially if we open
> up to
> everyday Emacs code in Common lisp. Basically it would be problematic if
> Common
> lisp could violate certain assumptions the Emacs code makes, like
> running "single threaded".
> Maybe this could be contained by hiding it somehow, but isn't all we
> get another internal implementation then?
> If the developers prefer to do the internal implementation in Common
> Lisp/Emacs Lisp rather than C/Emacs lisp and have
> easier access to expose some libraries then that is another thing.
>
>
> So when people talk about Emacs Lisp transitioning to Common Lisp,
> please specify exactly what you want.
>


Exactly my thoughts. My fear is that this supposed transition to Common
Lisp with fragment the emacs user base.. some will stick with elisp and
some will move over to CL. Elisp is working very well for configs and
packages. We should rather stick with it and keep on growing the codebase
in the same language.

(If Elisp is completely discarded, we will not have enough people to
convert *all* existing cool packages discovered and yet to be discovered
from elisp to CL.)

So it is a lose-lose situation whether Elisp and CL co-exist or even if CL
completely replaces Elisp.
-- 

Kaushal Modi