How can we generate a Traceback?

Question

When raising an exception, it is often useful to know which line of code
executed before the exception was raised. i.e., the message-send stack,
the Forte equivalent to a Smalltalk "walkback" window. We know such a
thing is possible because Forte generates one when you send a message to
the NIL object (see attachment). However, in our own code, Forte merely
recounts the line of code which raised our exception - not necessarily
useful.
Does anyone know how to make Forte print the Traceback, in a clean way?
That is, other than intentionally generating a run-time error such as
sending a message to NIL? Setting the severity level on the exception
makes no difference. Nor does using one of Forte's "System" exceptions
seem to help.
Example of a Traceback:
Note: "CastingTest.Levels at line 1" is the actual "culprit" code
=============================================
EagleOperationsMgr:Security
SYSTEM ERROR: Trying to invoke a method on a NIL object (qqsp_String,
55).
Traceback:
CastingTest.AbstractInstantiationTest at line 2
CastingTest.Levels at line 1
C++ Method(s)
InterfaceManager.RunRunner at offset 102
Class: qqos_SystemException
Error #: [901, 60]
Detected at: qqin_Interpret at 10
Last TOOL statement: method CastingTest.AbstractInstantiationTest,
line 2
Error Time: Tue Feb 25 12:36:06
Exception occurred (locally) on partition "Forte_cl0_Client",
(partitionId
= 732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1, taskId =
[732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1.4]) in
application
"Forte_cl0", pid 155 on node W133637 in environment EagleDev.
Example of a User-Generated SystemException - no Traceback:
Note: CastingTest.Levels at line 1 is not mentioned - difficult to debug
=============================================
EagleOperationsMgr:Security
USER ERROR: abc
Class: qqos_SystemException
Last TOOL statement: method CastingTest.ExceptionTest, line 4
Error Time: Tue Feb 25 12:39:45
Exception occurred (locally) on partition "Forte_cl0_Client",
(partitionId
= 732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1, taskId =
[732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1.4]) in
application
"Forte_cl0", pid 155 on node W133637 in environment EagleDev.

Answer 1

Why not
task.errormgr.showerrors(TRUE);
or am I missing something?
[email protected] writes:
> Francis Blesso/BOSTON/PART/CSC
> 02/25/97 08:01 PM
>
> In order to generate a traceback cleanly, I belive you'll have to wait
> until Forte release 3.
> The taskhandle class will have a method which returns a TextData object
> describing the
> stack trace.
>
> I've used the same trick of invoking a method on a nil object but only
> temporarily. Its ugly
> and makes it hard to handle the intended exception.
>
> If suppose you could also run your project from the debugger view the
> task's call
> stack once the exception is raised.
>
>
> Francis Blesso
>
> CSC Consulting and Systems Integration.
> [email protected]
>
> ///////////////////////////////////////////////////////////////////////////
> ///////////////
>
> When raising an exception, it is often useful to know which line of code
> executed before the exception was raised. i.e., the message-send stack,
> the Forte equivalent to a Smalltalk "walkback" window. We know such a
> thing is possible because Forte generates one when you send a message to
> the NIL object (see attachment). However, in our own code, Forte merely
> recounts the line of code which raised our exception - not necessarily
> useful.
>
> Does anyone know how to make Forte print the Traceback, in a clean way?
> That is, other than intentionally generating a run-time error such as
> sending a message to NIL? Setting the severity level on the exception
> makes no difference. Nor does using one of Forte's "System" exceptions
> seem to help.
>
>
>
> Example of a Traceback:
> Note: "CastingTest.Levels at line 1" is the actual "culprit" code
> =============================================
> EagleOperationsMgr:Security
> SYSTEM ERROR: Trying to invoke a method on a NIL object (qqsp_String,
> 55).
> Traceback:
> CastingTest.AbstractInstantiationTest at line 2
> CastingTest.Levels at line 1
> C++ Method(s)
> InterfaceManager.RunRunner at offset 102
>
> Class: qqos_SystemException
> Error #: [901, 60]
> Detected at: qqin_Interpret at 10
> Last TOOL statement: method CastingTest.AbstractInstantiationTest,
> line 2
> Error Time: Tue Feb 25 12:36:06
> Exception occurred (locally) on partition "Forte_cl0_Client",
> (partitionId
> = 732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1, taskId =
> [732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1.4]) in
> application
> "Forte_cl0", pid 155 on node W133637 in environment EagleDev.
>
>
> Example of a User-Generated SystemException - no Traceback:
> Note: CastingTest.Levels at line 1 is not mentioned - difficult to debug
> =============================================
> EagleOperationsMgr:Security
> USER ERROR: abc
> Class: qqos_SystemException
> Last TOOL statement: method CastingTest.ExceptionTest, line 4
> Error Time: Tue Feb 25 12:39:45
> Exception occurred (locally) on partition "Forte_cl0_Client",
> (partitionId
> = 732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1, taskId =
> [732D9D45-3D64-11D0-BC65-4A0594FDAA77:0x14dc:0x1.4]) in
> application
> "Forte_cl0", pid 155 on node W133637 in environment EagleDev.
>
>
>
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-= Thor (David Thor Collard) | Be the tree rooted.
-= [email protected] | http://www.alta-oh.com/~thor/
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-= What no one seems to comprehend is that there is only one battle,
-= and that we are compelled by our nature and the nature of reality
-= to fight it again and again.
-= Rannulph Junah in "The Legend of Bagger Vance" by Steve Pressfield
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-