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000019_icon-group-sender _Mon Dec 19 09:54:03 1994.msg
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1995-02-09
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Received: by cheltenham.cs.arizona.edu; Mon, 19 Dec 1994 11:54:18 MST
Message-Id: <9412191846.AB00763@iias.images.alaska.edu>
Mime-Version: 1.0
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Date: Mon, 19 Dec 1994 09:54:03 +0000
To: icon-group@cs.arizona.edu
From: sysmgr@iias.images.alaska.edu (IIAS System Manager)
Subject: Re: Backtracking in Icon
Errors-To: icon-group-errors@cs.arizona.edu
>>
>>"once you finally understand it, it is hard to live without".
>>
>No Sir, not necessarily. You may replace the backtracking, whose role is to
>provide you an alternative collection of solutions to a given problem, by
>a LAZY LIST of these solution. So, the lazy functional languages give you
>an alternative. You may find some information about this in quite respectable
>books, for example Henderson, or Abelsson&Sussman.
>
He didn't say it was impossible to live without backtracking once you have
seen the light, just difficult. I'm not sure what you mean by "lazy lists"
- I haven't heard that term before, but if I understand what you mean then
isn't using arrays/lists to hold intermediate results then returning to one
of those previous states to continue along another path also backtracking?
That's what I call it, but perhaps I am misusing the term.
Walter R.