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From: Andy Wingo <wingo@pobox.com>
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Subject: Re: A question on a piece of code written using call/cc
Date: Wed, 01 Sep 2010 08:35:48 -0700
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To: Yi DAI <plm.day@gmail.com>
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In-Reply-To: <AANLkTimtD1_hvLqS4tkrwXONuVBdtU=qAYJ12oGt1HrX@mail.gmail.com>
	(Yi DAI's message of "Wed, 1 Sep 2010 12:10:52 +0800")
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Xref: news.gmane.org gmane.lisp.guile.user:8134
Archived-At: <http://permalink.gmane.org/gmane.lisp.guile.user/8134>

Hi Yi,

On Tue 31 Aug 2010 21:10, Yi DAI <plm.day@gmail.com> writes:

> (let ((n 0)=C2=A0
> =C2=A0=C2=A0 =C2=A0 =C2=A0(c (call/cc (lambda (k) k))))
> =C2=A0=C2=A0(display n)
> =C2=A0=C2=A0(newline)
> =C2=A0=C2=A0(set! n (+ n 1))
> =C2=A0=C2=A0(c c))
>
> What I wanna do is try to print out the sequence of natural numbers
> using call/cc. On Guile, it works well. But other implementations
> (Chicken, Bigloo, Racket) all print out (an infinite sequence of) 0. I
> am puzzled. Any idea?

Guile from master returns a sequence of zeros as well. I'm not sure why
older Guile behaves differently.

I think in any case for your program to be correct, you need to use let*
instead of let.

Andy
--=20
http://wingolog.org/