Report development without the need to restart GnuCash

[Charles Day]

On Fri, May 23, 2008 at 12:23 AM, Torsten Edeler <torsten at edeler.org> wrote:

> Hi Charles.
>
> Well I didn't thing of a bug in the first place. I just thought my method
> hasn't just been intended my the report framework.
> I could open a bug if it is one (and not a feature) :-)
>

If I read your code correctly, you are passing your custom option loading
procedure (named options-generator) and your custom renderer (named
renderer), to a GnuCash reporting API procedure, gnc:define-report.  And
apparently when these functions get called, an exception that occurs in the
custom renderer is handled gracefully, but an exception that occurs in the
custom option loader crashes the entire GnuCash application. From my way of
thinking, the API should protect itself from any possible exception that
might arise in the renderer OR the option loader.

Regarding gnc-backtrace-if-exception: I don't have any clue what you are
> talking about. As I wrote I'm very new to GnuCash and to Scheme. So if you
> could describe your propose in more detail I could try to implement it.
>

Your code seems OK. I would think that the GnuCash reporting API should
protect itself from exceptions that may arise in your custom code. But since
I am not intimately familiar with reporting, perhaps one of the other
developers could comment?

If you want to try out exception handling, I would think that something like
this would work. If an exception occurs, a backtrace is generated and (I
think) the procedure returns #f:

(define (options-generator)
  (gnc:backtrace-if-exception
    (lambda ()
      (load "/home/torsten/.gnucash/reports/myoptions.scm")
      (myoptions)))
)

By the way, I use vi for editing Scheme and C. It does do syntax
highlighting, and parenthesis matching (% key) is really nice. But the
learning curve is steep,and I am a vi diehard. :)

Cheers,
Charles


> btw: I currently use Kate for editing Scheme files and I'm not really
> satisfied with it. First of all there seems to be a bug in the bracket
> matching and second it does not support code folding for Scheme. Could
> somebody out there propose another (GUI) editor to me? I'm not gonna use
> Emacs :-) I would use it too less to get familiar with all that cryptic key
> combinations.
>
> Regards,
> Torsten
>
> 2008/5/22 Charles Day <cedayiv at gmail.com>:
>
> On Thu, May 22, 2008 at 11:09 AM, Torsten Edeler <torsten at edeler.org>
>> wrote:
>>
>>> Hi everybody.
>>>
>>> I'm quite new to GnuCash. Recently I felt the need to make my own report
>>> adapted to my needs, since the existing reports were not suitable. After
>>> taking a look to this obscure language Scheme - which I will probably
>>> never
>>> like :-) - the question rised how to develop reports without having the
>>> need
>>> to restart the whole application after a little bit of the report had to
>>> be
>>> changed. I searched the mailing list, but hadn't found anything usefull.
>>>
>>> I would like to present my solution to that problem to you. Perhaps it
>>> has
>>> already been solved (probably more elegant) by some of you or I missed it
>>> in
>>> the ml. Anyway this is what I use at the moment for development.
>>>
>>> I have the report file which is load by GnuCash on Startup:
>>>
>>> (define pagename-general "General")
>>> (define (options-generator)
>>>    (load "/home/torsten/.gnucash/reports/myoptions.scm")
>>>    (myoptions)
>>> )
>>>
>>>
>>> (define (renderer options)
>>>    (load "/home/torsten/.gnucash/reports/renderer.scm")
>>>    (myrenderer options)
>>> )
>>>
>>>
>>> (let ()
>>>  (gnc:define-report
>>>   'version 1
>>>   'name (N_ "Trivial Example")
>>>   'options-generator options-generator
>>>   'renderer renderer)
>>> )
>>>
>>> As you can see the renderer and the options-generator include a file
>>> load.
>>> So everytime GnuCash executes one of the functions, a fresh version of
>>> the
>>> file is loaded and executet. The files itself defines a function
>>> "myoption"
>>> and "myrenderer" respectively. Note that the option-generator is only
>>> executed after loading the report from the menu (or on startup), whereas
>>> the
>>> renderer is also executet after reloading or modification of the options.
>>>
>>> Unfortunatly GnuCash is very sensible to errors in the option-generator,
>>> since it simple terminates the whole application.
>>
>>
>> This seems patently ungraceful. Why not include a
>> gnc-backtrace-if-exception type of wrapper on options to prevent crashing?
>> Is there a bug filed for this already? (Although I do a fair bit of work in
>> Scheme, I plead ignorance to the report infrastructure.)
>>
>> Cheers,
>> Charles
>>
>>
>>> The renderer behaves more
>>> nicely: Only an error message is displayed in the report window and one
>>> has
>>> the chance to modify the file and reload the report.
>>>
>>>
>>> I hope this little texts helps some of you. At least it would have helped
>>> me
>>> :-)
>>>
>>> regards,
>>> Torsten
>>> _______________________________________________
>>> gnucash-user mailing list
>>> gnucash-user at gnucash.org
>>> https://lists.gnucash.org/mailman/listinfo/gnucash-user
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>>>
>>
>>
>