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From: | Daniel Kraft |
Subject: | Re: %nil once again |
Date: | Mon, 20 Jul 2009 10:12:42 +0200 |
User-agent: | Thunderbird 2.0.0.0 (X11/20070425) |
Ken Raeburn wrote:
On Jul 19, 2009, at 16:10, Neil Jerram wrote:BTW, I implemented also the function bindings of symbols using this fluid-based dynamic scoping at the moment -- but on second thought, there's no scoping at all for function slots (all are global), is there?No, I don't think there is. `let' can't operate on function slots.Not in the main emacs lisp implementation. However, cl-macs.el provides an "flet" macro that does work on function slots; it uses the "letf" macro which expands to include a use of unwind-protect to do its dirty work.
But that's not part of the real "elisp semantics", and so if we don't want to include this as a genuine extension into Guile's compiler, we don't have to use the fluids for function slots.
With unwind-protect and friends one can, just like in emacs, implement this functionality, even without a fluid implementation.
However, if you agree that this would be a useful feature (dynamic scoping of functions) I can of course implement this as an extension to elisp...? I agree that it might be of use sometimes, but am not convinced it is really "necessary".
Yours, Daniel -- Done: Arc-Bar-Cav-Ran-Rog-Sam-Tou-Val-Wiz To go: Hea-Kni-Mon-Pri
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