Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdcad!sun!pitstop!sundc!seismo!uunet!pdn!colin
From: colin@pdn.UUCP (Colin Kendall)
Newsgroups: comp.lang.smalltalk
Subject: Tektronix error handler implementation troubles
Keywords: Tektronix error handler HOOPLA ParcPlace
Message-ID: <3291@pdn.UUCP>
Date: 27 May 88 10:01:49 GMT
Organization: Paradyne Corporation, Largo, Florida
Lines: 39

In the April edition of HOOPLA, Ward Cunningham of Tektronix 
describes an elegant error handler, and includes the methods
used to implement it in Tektronix LOS Smalltalk. We are trying
to implement it in ParcPlace VI2.2, with no success.  

The article shows the instance variable 'errorHandler' added to
class Process. When we try to do this, the image dies (no keyboard
or mouse response) and a core image is written. 

Suspecting that this had to do with the obsoleting or updating
of the active process, I commented out the "self updateInstancesFrom:
oldClass" in
ClassDescription>validateFrom:in:instanceVariableNames:methods:; this
helped a little, inasmuch as it produced some Transcript error
messages before core dumping, to wit:

Message not understood: priority
ProcessorScheduler>activePriority
BlockContext>newProcess
ControlManager>activeController:

Type s for more stack, anything else restarts...

Unfortunately typing s or anything else had no effect.

We have a call in to ParcPlace about this, but my experience with
them is that they make excellent software but their customer 
service is effectively non-existent.

Has anyone implemented this stuff?  Any help would be appreciated.
If I get it working I'll post the solution, if any interest is
expressed.


-- 
Colin Kendall				Paradyne Corporation
{gatech,akgua}!usfvax2!pdn!colin	Mail stop LF-207
Phone: (813) 530-8697			8550 Ulmerton Road, PO Box 2826
					Largo, FL  33294-2826