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Another omission: global lexicals
- To: "Daniel L. Weinreb" <DLW@SCRC-QUABBIN.ARPA>
- Subject: Another omission: global lexicals
- From: Rob MacLachlan <RAM@C.CS.CMU.EDU>
- Date: Sun, 15 Dec 1985 22:40:00 -0000
- Cc: common-lisp@SU-AI.ARPA
- In-reply-to: Msg of 15 Dec 1985 17:55-EST from Daniel L. Weinreb <DLW at SCRC-QUABBIN.ARPA>
Yes, we seem to be talking about the same thing. I believe you
have the right model for interaction with specials: there is none.
Unfortunately this means that shallow-binding implementations would
have to have separate lexical and special value cells, since you could
do something like this:
(defglobal foo :global)
(let ((foo :special))
(declare (special foo))
(defun bar ()
(format t "~S or ~S, take you pick."
foo (locally (declare (special foo)) foo)))
This doesn't mean that your symbol needs another slot though. You
could keep the lexical value cells somewhere else (such as on the
PLIST!!), since you only need to locate the value cell at load time.