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From: wysiwyg@glympton.airtime.co.uk (Adam L Rice)
Newsgroups: comp.object,comp.lang.eiffel,comp.lang.c++,comp.lang.beta,comp.lang.java,comp.lang.sather
Subject: Re: What Should An Exception Handling Do? -- Clarification of rules
Date: 2 Apr 1996 08:11:44 +0100
Organization: The Rice family.
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References: <4irn11$7ln@mimas.brunel.ac.uk> <4j03p4$fbt@hoho.quake.net> <Doq3sv.MzA@research.att.com> <vwjg2ao6hqp.fsf@osfb.aber.ac.uk>
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>The exception facility of e.g. C++ is merely a (rather ad-hoc and
>opaque) way of allowing the definition of what are in effect dynamically
>scoped procedure names, forcibly coupled with non-local control
>transfer.

So, let me see if I've understood. What you're basically saying is that
instead of doing (in Java):

try {
  sock = new Socket("wallawalla.mit.edu", 3456);
} catch (IOException e) {
  ... // handle the exception
}
.... // use the socket

we should do something like:

if (Socket.ConnectWillWork("wallawalla.mit.edu", 3456) {
  sock = new Socket("wallawalla.mit.edu", 3456);
  ... // use the socket
} else {
  ... // handle the exception
}

Hmmmm... that's a lovely code style! I think we can call this techique
'APIx2', for obvious reasons.

But I'm not entirely clear, it might be you were saying we should do:

sock = new Socket("wallawalla.mit.edu", 3456, new CantConnectHandler());
if (!CantConnectHandler.ConnectFailed) {
  ... // use the socket
}

// some time later
Class CantConnectHandler implements IOExceptionHandler {
  public int ConnectFailed=false;
  public handle(Object context) {
    ... // handle the exception
  }
}

Hmmm... that too is delightful! I can't think of a good name for it, so I
think 'VerboseAndSlow' will have to do, though it doesn't capture the true
joy of using this programming style. I can't help but feel that it's a real
pity that the Java developers weren't open-minded enough to provide
alternate APIs for people who wanted to program using these coding styles.


Well, I say one thing for you computer scientist types, you certainly know
how to make a guy glad of what he's got! I'll never complain about having to
write a try ... catch statement again!

Have a nice day!

,==========================================================================.
| \    /\/( |\    /\//'   | Adam L Rice -|- wysiwyg@glympton.airtime.co.uk |
|  \/\/ /  )| \/\/ / \_|  | Resume: http://www.csv.warwick.ac.uk/~mauhb/cv |
`=========================================================================='