missing operand at _@_

[Helmut Jarausch]

Hi,

I'm using an application (TkRat) which is built with Tcl/Tk 8.5a6 and
htmlwidget (from CVS).
When opening a message which contains html, i.e. htmlwidget is used,
I get a popup window saying

missing operand at _@_
in expression " - _@_"

What could be the reason and how can I find out the faulty code?

Many thanks for a hint,

Helmut Jarausch

Lehrstuhl fuer Numerische Mathematik
RWTH - Aachen University
D 52056 Aachen, Germany

[miguel sofer]

On May 5, 6:36 am, Helmut Jarausch <jarau...@skynet.be> wrote:
> Hi,
>
> I'm using an application (TkRat) which is built with Tcl/Tk 8.5a6 and
> htmlwidget (from CVS).
> When opening a message which contains html, i.e. htmlwidget is used,
> I get a popup window saying
>
> missing operand at _@_
> in expression " - _@_"

The popup typically will offer to show details - does it? Those
details are a stack trace, which we'll need to be able to offer any
precise help. Without more info, all that can be said is that the code
is trying to eval a malformed expression, as in

% expr -

missing operand at _@_
in expression "-_@_"

Maybe something like

% set x {}; set y {}; expr $x-$y

missing operand at _@_
in expression "-_@_"

which would be another reason to brace your expressions :)

% expr {$x-$y}
can't use empty string as operand of "-"

>
> What could be the reason and how can I find out the faulty code?
>
> Many thanks for a hint,
>
> Helmut Jarausch

Hope this helps; if you need more assistance, please provide more
details. Cheers

Miguel

[Helmut Jarausch]

miguel sofer wrote:
> On May 5, 6:36 am, Helmut Jarausch <jarau...@skynet.be> wrote:
>> Hi,
>>
>> I'm using an application (TkRat) which is built with Tcl/Tk 8.5a6 and
>> htmlwidget (from CVS).
>> When opening a message which contains html, i.e. htmlwidget is used,
>> I get a popup window saying
>>
>> missing operand at _@_
>> in expression " - _@_"
>
> The popup typically will offer to show details - does it? Those

Many thanks.
Unfortunately it didn't show anything else.
Therefore the question is, how can I debug it?
(I don't develop Tcl code myself) How can I start my application
under a debugger where I can get control when such an exception
occurs?

> details are a stack trace, which we'll need to be able to offer any
> precise help. Without more info, all that can be said is that the code

snip

Helmut.

--

[Michael Schlenker]

Helmut Jarausch schrieb:

> miguel sofer wrote:
>> On May 5, 6:36 am, Helmut Jarausch <jarau...@skynet.be> wrote:
>>> Hi,
>>>
>>> I'm using an application (TkRat) which is built with Tcl/Tk 8.5a6 and
>>> htmlwidget (from CVS).
>>> When opening a message which contains html, i.e. htmlwidget is used,
>>> I get a popup window saying
>>>
>>> missing operand at _@_
>>> in expression " - _@_"
>>
>> The popup typically will offer to show details - does it? Those
>
> Many thanks.
> Unfortunately it didn't show anything else.
> Therefore the question is, how can I debug it?
> (I don't develop Tcl code myself) How can I start my application
> under a debugger where I can get control when such an exception
> occurs?

Usually you get a stack trace from a bgerror proc, but you could use
something from here: http://wiki.tcl.tk/473 to use a debugger to step
into things (RamDebugger for example).

Michael