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left to right order of evaluation
- To: common-lisp @ SU-AI
- Subject: left to right order of evaluation
- From: George J. Carrette <GJC @ MIT-MC>
- Date: Wed, 21 Nov 1984 18:11:00 -0000
Or, "is funcall really considered harmfull?"
Q:
; given:
(defun f ()
(fset 'g #'h)
(prog1 (g (i))
(fset 'g #'h)))
(defun h (ignored)
"left to right is strict")
(defun i ()
(fset 'g #'(lambda (ignored) "left to right is violated")))
; Is (F) => "left to right is strict"
; or => "left to right is violated"
The question is, does common-lisp define the result of (F) in
this case?
This is related to the question of the equivalence of
(G ...) and (FUNCALL (PROGN #'G) ...)
where I add the PROGN to indicate that I don't want compiler
optimization to determine this.
I've observed that on some machines this equivalence is
rather designed in, that a call of a function and a FUNCALL
are exactly the same instruction sequence, but on some
machines they are very different.
-gjc