Subject: Re: Dynamic-wind
From: rpw3@rigden.engr.sgi.com (Rob Warnock)
Date: 5 Nov 2001 08:15:12 GMT
Newsgroups: comp.lang.scheme
Message-ID: <9s5hqg$5pcji$1@fido.engr.sgi.com>
felix <felixundduni@freenet.de> wrote:
+---------------
| If you consider call/cc + dynamic-wind (the way it currently exists)
| a problem.  I have to admit that I'm perfectly happy the way it is
| (besides a small point: the undefined behaviour of invoking continuations
| inside winder-thunks).
+---------------

Unfortunately, that "small point" makes it impossible to use
call/cc + dynamic-wind as the basis for an exception system.
In fact, within what's guaranteed by R5RS, you can't even
implement a simple "catch/throw" with it!!


-Rob

-----
Rob Warnock, 30-3-510		<rpw3@sgi.com>
SGI Network Engineering		<http://www.meer.net/~rpw3/>
1600 Amphitheatre Pkwy.		Phone: 650-933-1673
Mountain View, CA  94043	PP-ASEL-IA

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