Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!diego.llnl.gov!miller
From: miller@lll-crg.llnl.gov (Patrick Miller)
Newsgroups: comp.lang.functional
Subject: Implementing Error Values
Keywords: pointers, papers, paraphernalia, error values, implementation
Message-ID: <86438@lll-winken.LLNL.GOV>
Date: 20 Nov 90 16:46:43 GMT
Sender: usenet@lll-winken.LLNL.GOV
Reply-To: miller@lll-crg.llnl.gov (Patrick Miller)
Organization: Lawrence Livermore National Laboratory
Lines: 26
Nntp-Posting-Host: diego.llnl.gov

I'm looking for pointers to papers about implementing error values in
functional languages (or other styles).  By error values, I mean that
the value of a calculation is replaced by a placeholder denoting the
error.  This allows some form of error handling without invoking the
concept of global state.

Example: (plus (div a 0) (plus b c))	;;; [ (a/0) + (b+c) ]
	 
	 The value of (div a 0) is ERROR.
	 Therefore the value of (plus (div a 0) (plus b c))
	 is also ERROR.

What I'm especially looking for is info on implementations of these
values.

Thanks,
Pat


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Pat Miller				     Professional Student
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