Article View: comp.lang.functional
Article #696Re: Implementing Error Values
From: Pablo A. Straub
Date: Fri, 07 Dec 1990 15:57
Date: Fri, 07 Dec 1990 15:57
20 lines
1658 bytes
1658 bytes
In article <1990Dec6.205610.1022@lescsse.uucp> dnsurber@lescsse.uucp (Douglas Surber) writes:
. . .
Assume that exceptions are added to the domain just above bottom and that they
are indistinguishable from bottom except by a special function catch
. . . [several examples and ideas]
E3
WHERE
E3 = ... [expression with a divide by zero and an infinite recursion]
The value of E3 is bottom. Even though the evaluator has determined that
there is at least one error present, it must press on until it finds a really
bad error, that is bottom. This does not seem like a good property for an
exception handling mechanism.
I see nothing wrong with collecting all errors: it preserves determinism.
If exceptions are really exceptional there is little waste. The value of
E3 above is indeed bottom (you should not expect your exception handling
mechanism to help you with the halting problem).
Pablo Straub
Technical Details
Message-ID:
<28380@mimsy.umd.edu>Path:
arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!haven!mimsy!jogger.cs.umd.edu!straubReferences:
<86438@lll-winken.LLNL.GOV> <1990Nov24.121432.29282@newcastle.ac.uk> <4043@osc.COM> <1990Dec6.205610.1022@lescsse.uucp>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!haven!mimsy!jogger.cs.umd.edu!straub From: straub@jogger.cs.umd.edu (Pablo A. Straub) Newsgroups: comp.lang.functional Subject: Re: Implementing Error Values Keywords: pointers, papers, paraphernalia, error values, implementation Message-ID: <28380@mimsy.umd.edu> Date: 7 Dec 90 15:57:28 GMT References: <86438@lll-winken.LLNL.GOV> <1990Nov24.121432.29282@newcastle.ac.uk> <4043@osc.COM> <1990Dec6.205610.1022@lescsse.uucp> Sender: news@mimsy.umd.edu Reply-To: straub@jogger.cs.umd.edu (Pablo A. Straub) Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 20