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From: "B. Pym"
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Stack overflow problem
Date: Mon, 2 Sep 2024 20:14:19 -0000 (UTC)
Organization: A noiseless patient Spider
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> > (defun nums (n) (loop for i from 1 to n collect i))
> >
> > (defmethod sum ((x null)) 0)
> > (defmethod sum ((x list)) (+ (first x) (sum (rest x)))
> >
> > (sum (nums 100)) => Stack overflow.
> >
> > I was hoping someone could toss some insight my way as to why this is.
>
> The recursion is simply too deep.
>
> If you're blowing out at 100 deep, you are probably running
> the code interpreted, which would add a bunch of additional
> stack frames. If you compile the methods, you'll probably
> get an order of magnitude farther.
>
> But you could just write instead:
>
> (reduce #'+ (nums 100))
> or
> (loop for i from i to n summing i)
>
> and not have to worry about the stack.
Gauche Scheme:
(define-method object-apply ((lst )) (fold + 0 lst))
gosh> '(1 3 5 7 9)
(1 3 5 7 9)
gosh> ('(1 3 5 7 9))
25
gosh> ((iota 333 1 2))
110889