[Seaside-dev] exception handler instance creation

[John O'Keefe]

Julian -
It was a lot more work to shape my head around the idea than it was to do
the code :-)

John O'Keefe [|], Principal Smalltalk Architect, Instantiations Inc.


On Tue, Jan 6, 2009 at 2:07 PM, Julian Fitzell <jfitzell at gmail.com> wrote:

> Oh, cool. Was it difficult to get working?
>
> The ANSI standard is confusing and ambiguous in places so it's not
> surprising that implementations still vary. The fact that all the
> implementations seem to require some modifications to make this work
> shows, if nothing else, that nobody else is implementing their own
> Exception Selectors, though. :)
>
> I just tried a simple test on GemStone and it looks like they will
> have to implement #try:on:do: at the moment to make it work. Though,
> from a quick glance, they may be able to tweak things so only the ANSI
> ExceptionSelector protocol is necessary.
>
> Julian
>
> On Tue, Jan 6, 2009 at 7:02 PM, John O'Keefe
> <wembley.instantiations at gmail.com> wrote:
> > Julian -
> > OK, it now works on VA Smalltalk -- at least the SUnit tests think so :-)
> > You are right that many of us implementors of ANSI don't always get it
> > correct.  Clearly the standard separates the idea of an
> <exceptionSelector>
> > from the various other exception protocols.
> > John O'Keefe [|], Principal Smalltalk Architect, Instantiations Inc.
> >
> >
> > On Thu, Jan 1, 2009 at 9:33 AM, Julian Fitzell <jfitzell at gmail.com>
> wrote:
> >>
> >> Hi John,
> >>
> >> Darn... I was following the ANSI standard... ;) it says that an
> >> exception selector needs to implement #handles: and #, which we do on
> >> both the class and instance side. On most systems this would include
> >> the Exception class and instances of ExceptionSet. How does VA
> >> implement ExceptionSet if #on:do: is so restrictive?
> >>
> >> Lukas took a quick look at his VA image and says it looks like
> >> WAExceptionHandler might just need an implementation of #handles:do:
> >> added in the VA port but I don't have a Windows install handy to look
> >> myself. I added some tests in Seaside-Tests-Core-jf.32 that should
> >> help verify directly if it's working or not, though.
> >>
> >> Do you think it's a solvable problem on VA? I just looked at VW and it
> >> looks like they would need to implement #isExceptionHandler in their
> >> compatibility package.
> >>
> >> Dale, I haven't got Gemstone installed on this new laptop yet either.
> >> Do you foresee problems getting this to work on your end?
> >>
> >> Obviously if this is going to be a huge compatibility problem we
> >> should rethink but I think the implementation is cleaner this way
> >> otherwise.
> >>
> >> Julian
> >>
> >> On Wed, Dec 31, 2008 at 8:28 PM, John O'Keefe
> >> <wembley.instantiations at gmail.com> wrote:
> >> > Julian -
> >> > I'm back to work after a week and got a bad surprise.
> >> > Seaside-Core-jf.349 and the associated changes to other packages has
> >> > completely broken the VA Smalltalk port.  Our implementation of
> >> > Block>>#on:do: expects a class as its first argument (and in
> particular,
> >> > the
> >> > class must be Exception or a subclass of Exception).  The same seems
> to
> >> > be
> >> > true of VW.
> >> >
> >> > But with Seaside-Core-jf.349 #on:do: is getting a WAExceptionHandler
> >> > class
> >> > (or subclass of it) as the first argument <exception selector> and
> then
> >> > with
> >> > Seaside-Core-jf.353 #on:do: is getting an instance of
> WAExceptionHandler
> >> > (or
> >> > a subclass of it) as the first argument.  In either case, we fall over
> >> > because the WAExceptionHandler class/instance does not understand any
> of
> >> > the
> >> > messages sent by #on:do: to the <exception selector>.
> >> > Since WAExceptionHandler is in the base, I assume it should be
> portable.
> >> > I have reverted to Seaside-Core-lr.348 and Seaside-Development-lr.53
> for
> >> > the
> >> > time being and things seem to be working OK again.
> >> > John O'Keefe [|], Principal Smalltalk Architect, Instantiations Inc.
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