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From: ram@spice.cs.cmu.edu (Rob MacLachlan)
Newsgroups: net.lang.lisp
Subject: Re: call/cc and proper tail recursion
Message-ID: <1087@spice.cs.cmu.edu>
Date: Sat, 1-Nov-86 02:27:33 EST
Article-I.D.: spice.1087
Posted: Sat Nov  1 02:27:33 1986
Date-Received: Mon, 3-Nov-86 22:40:39 EST
References: <20000003@uicsrd> <20000010@uicsrd>
Organization: Carnegie-Mellon University, CS/RI
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    From: harrison@uicsrd.CSRD.UIUC.EDU
    Newsgroups: net.lang.lisp
    Subject: Re: call/cc and proper tail recursion
    I agree that global analysis of the program is the answer; my point is that
    the definition of scheme makes it seem as though one can state simply that
    tail recursion can be made as efficient as iteration, which simply isn't so
    in the presence of call/cc.


Proof notwithstanding, you are totally wrong.  As was earlier mentioned by
someone who knew what they were talking about, "call with current
continuation" is implemented in a somewhat expensive way so that tail
recursion still does work.  Basically what you do is copy the entire stack
onto the heap.  Your time would be better spent if you avoided proving
impossible things which have already been done.