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common lisp- &environment objects
- To: Guy Steele <gls@THINK.ARPA>
- Subject: common lisp- &environment objects
- From: "Scott E. Fahlman" <Fahlman@CMU-CS-C.ARPA>
- Date: Thu, 06 Jun 1985 02:06:00 -0000
- Cc: common-lisp@SU-AI.ARPA
- In-reply-to: Msg of 5 Jun 1985 16:25-EDT from Guy Steele <gls at THINK.ARPA>
- Sender: FAHLMAN@CMU-CS-C.ARPA
The book is silent in the question of the extent of environments as delivered
to &environment bindings in DEFMACRO, hook functions, etc. What shall we say?
One false move here and we have not Lisp but Conniver. How about
requiring "dynamic" extent for environment objects, and no more? Will
that take care of the needs for macro-expansion, steppers, and so on?
True, you could imagine cute ways of using environments that outlive
their invocations, but I REALLY don't want to pay for those cute uses
with inefficiency or severe constraints on the implementor. If anyone
wants to implement Conniver in Common Lisp, I can supply the old Maclisp
code, but let's not drag down Common Lisp itself.