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000015_icon-group-sender_Wed Feb 12 08:12:35 2003.msg
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Received: (from root@localhost)
by baskerville.CS.Arizona.EDU (8.11.1/8.11.1) id h1CFCAE14778
for icon-group-addresses; Wed, 12 Feb 2003 08:12:10 -0700 (MST)
Message-Id: <200302121512.h1CFCAE14778@baskerville.CS.Arizona.EDU>
From: "Andrew Hamm" <ahamm@mail.com>
X-Newsgroups: comp.lang.icon
Subject: Re: data values
Date: Wed, 12 Feb 2003 10:28:04 +1100
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To: icon-group@cs.arizona.edu
Errors-To: icon-group-errors@cs.arizona.edu
Status: RO
ernobe wrote:
>
> The whole section immediately following, entitled "Data Backtracking"
> might as well be paraphrased as "There is such a thing as data
> backtracking". Would it be right to conclude from it that the success
> of expressions in a logical conjunction does not depend on the success
> of the final expression, while the success of the conjunction as a
> whole does?
The success of the entire conjunction depends on the success of all the
parts. If a "deeper" part fails, then the earlier parts are resumed to
squeeze out another possible result. If deeper parts keep failing, then
ultimately the earlier parts are driven to the point of their own failure,
so another backtrack happens. This can happen all the way back, until maybe
the first part also runs out of results, so then they have all failed in one
way or the other.
--
There's nowt wrong wi' owt what mitherin' clutterbucks don't barly grummit!
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