r15102 - gnucash/trunk - Fix three incorrect tests for swig-wrapped objects and one

[Andreas Köhler]

Hi,

Am Donnerstag, den 09.11.2006, 09:27 -0500 schrieb Andreas Köhler:
> Author: andi5
> Date: 2006-11-09 09:27:48 -0500 (Thu, 09 Nov 2006)
> New Revision: 15102
> Trac: http://svn.gnucash.org/trac/changeset/15102
> 
> Modified:
>    gnucash/trunk/
>    gnucash/trunk/src/business/business-reports/aging.scm
>    gnucash/trunk/src/business/business-reports/invoice.scm
>    gnucash/trunk/src/import-export/qif-import/qif-file.scm
>    gnucash/trunk/src/report/report-system/report.scm
> Log:
> Fix three incorrect tests for swig-wrapped objects and one
> initialization as #f instead of '(), the latter making qif imports work
> again. Remove also a few lines of old commented cruft.

Initially I wanted to complete chris' audit of scheme files, but I had
quite some difficulties determining whether a given variable is #f or
'() if it is to be considered non-existent. I understand that it is easy
and reasonable to wrap a NULL pointer as '(), so that it can be tested
with null?. But OHOH in a pure scheme context #f is nice too, as it is
the only thing with a false truth value.

Is there a way to easily see whether something missing, maybe passed 15
scheme frames down the stack) is #f or '()? Or can we mix them without
writing
(and obj (not (null? obj))), or
(or (not obj) (null? obj))
all the time?

I do not touch those scheme files very often, so if you think this is
trivia, I will not argue about that.

-- andi5