Greetings Ned,

Sorry to just pipe in here but I just have to say that I think you are the
ideal person to bring coherence to Squeak exception handling having seen
your considerable talent at Watkins-Johnson! I think Squeak really does need
exception handling capabilities similar to that we used at WJ.

Jerome the lurker.

> -----Original Message-----
> From: ned at whidbey.net [mailto:ned at whidbey.net]On Behalf Of Ned Konz
> Sent: Monday, July 24, 2000 9:09 AM
> To: squeak at cs.uiuc.edu
> Subject: Re: User interaction vs. headlessness vs. exception handling
>
>
> Les Tyrrell wrote:
> >
> > You might find the Messenger framework written by Paul Baumann
> > to be worth looking at.  I haven't yet had a chance to use it,
> > but plan to try it out in a few projects of mine coming up.
> >
> > Messenger was one of the frameworks that Paul brought to the
> > first Camp Smalltalk, so there is a desire ( if not the already
> > existing capability ) to have it in the Squeak Smalltalk environment
> > as well.  Information about Messenger, along with a link to the
> > downloadable files, can be found at:
> >
> > http://wiki.cs.uiuc.edu/CampSmalltalk/Messenger+project
>
> The problem with this is that it's still aimed at talking with people.
> My interest is more in non-interactive applications -- web servers,
> machine controllers, etc. -- that may never have a person with whom
> to communicate.
>
> There are two problems that I see with this:
>
> 1. Text-based error descriptions don't allow easy special-case handling.
> It is common to have to do one thing on a timeout (possibly different
> in different contexts), and another on a transient failure of another
> type, and yet another for a permanent failure.
>
> The Exception hierarchy allows for this (and text messages can ride
> along for free!)
>
> 2. There is a single recipient for the messages. Exception handling
> allows scoped, nested exception handling. If one context can't handle
> an exception, it can re-raise it. Or do something and raise another
> exception. And it can be handled in a context that can actually do
> something.
>
> --
> Ned Konz
> currently: Stanwood, WA
> email:     ned at bike-nomad.com
> homepage:  http://bike-nomad.com
>