Newsgroups: comp.lang.lisp
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Subject: Re: history mechanism (kbd) ??
References: <35vc52$262k@yuma.ACNS.ColoState.EDU> <35vet1$52j@tools.near.net> <363r03$q2i@nz12.rz.uni-karlsruhe.de>
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Date: Mon, 26 Sep 1994 20:44:05 +0000
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In article <363r03$q2i@nz12.rz.uni-karlsruhe.de>
           haible@ma2s2.mathematik.uni-karlsruhe.de "Bruno Haible" writes:

> This is stone age editing. Better use iron age editing:
> 
>   #.(cons '- (rest -))

It occured to me that my reply to your post used an example that
has another solutions:

#.(subst - '- '*)

This would work with my "simple" example, but not with even more
complex examples. Try changing the (- 3 4) to 7:

(max (+ 3 4) (- 3 4))

using:

(setf form -)
(setf (third form) 7)
(eval form)

or:

#.(append (butlast -) (list 7))

Hmmm....I'll need to work on this! ;-)

-- 
Future generations are relying on us
It's a world we've made - Incubus	
We're living on a knife edge, looking for the ground -- Hawkwind
