[Bese-devel] Dynamic environment and Arnesi

[Attila Lendvai]

Hello!

I'm missing special variables when using Arnesi, and I was thinking
wether it would be possible for Arnesi to give some support in this.
Could be I don't know enough about the CPS voodoo, but I think it's
possible for Arnesi to provide two functions in /cc code similar to
these:

(let/cc-dynamic name value)
(makunbound/cc-dynamic name)

The names are silly, but hopefully intuitive. The first one would
define a dynamic variable in the continuation, that could be looked up
from /cc code using (declare special) or some other similar way. The
second would remove that binding. Maybe the lookup method could also
be explicit, with a (lookup/cc-dynamic name).

Also it would be useful if these could be nested just like dynamic vars.

With the help of these we could emulate similar functionality as the
with-... macros and special variables in normal lisp code.

Am I missing something and this is already available in a form I don't
know about? If not, then is it possible to implement this feature? Was
anybody thinking about it? Does it make sense ignoring the details?

Thanks in advance,

- attila

(alias 101 on irc &no 'its not lisp code :)