Re: guile and emacs and elisp, oh my!

[Andy Wingo <wingo@pobox.com>]

Hi,

On Sun 25 Apr 2010 18:54, Richard Stallman <rms@gnu.org> writes:

>     Sure, Schemers ought to be encouraged to write
>     "(null? x)" rather than "(eq? x '())" but ... 
>     what about "(eq? x y)"?  
>
> My original plan was to have two execution modes,
> a Lisp mode in which () and Scheme's false object are equal,
> and a Scheme mode in which they were not equal.

That is something like what Guile does, except the mode can be
determined statically -- it's the language that the code is written in.
If it's elisp, they are equal, if it's scheme, they're not.

>     And: since Emacs lisp and Guile can't agree about
>     equality (whichever flavor) - how do I write a 
>     hash table library useful to both environments?
>
> It should hash all the kinds of nil the same.
> Then, as regards the comparison, it can depend on
> the execution mode as inherited from the caller.

Hashing nil, null, and false to the same value is probably a good idea.
Then if you use an elisp accessor, you get elisp semantics, or scheme
semantics with a scheme accessor.

Andy
-- 
http://wingolog.org/