Subject: Re: faking dynamic-wind ?
From: rpw3@rigden.engr.sgi.com (Rob Warnock)
Date: 20 Dec 2000 02:52:10 GMT
Newsgroups: comp.lang.scheme
Message-ID: <91p6sq$d4von$1@fido.engr.sgi.com>
Matthias Blume  <see@my.sig> wrote:
+---------------
| "felix" <felix@anu.ie> writes:
| > That's not the problem. If we can implement dynamic-wind in user-mode
| > (that's what we are talking about, remember?) then we *have* access
| > to the native call/cc.
| 
| That's not what I was talking about.  In R5RS, there is no native
| call/cc.  Period.  (The user-level implementation is just a way of
| faking R5RS-compliance.)
+---------------

I think there are at least two typos here. R5RS *has* both call/cc and
dynamic-wind native [see section "6.4 Control features"], and even R4RS
had native call/cc as an "essential procedure". Is this what you meant
to say instead?

	In R4RS, there is no native dynamic-wind. Period. (The user-level
	implementation is just a way of faking R5RS-compliance.)


-Rob

-----
Rob Warnock, 31-2-510		rpw3@sgi.com
Network Engineering		http://reality.sgi.com/rpw3/
Silicon Graphics, Inc.		Phone: 650-933-1673
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