[Zope] hasattr in tal:condition

Mon Mar 15 15:21:59 EST 2004

Thanks for the hint.

After some experimentation I realise that "exists:" does not help, 
because it does not have an "else" branch. If I set the exists condition 
on the body or a span tag, the defined results are visible only within 
that tag. An else branch must me simulated by a second condition on a 
tag, but that means that the whole content of the previous one needs to 
be repeated. However, the whole point of the test was to re-use all the 
content except for a single statement at the beginning that determines 
where the results come from. As a result, a neater solution seems to be 
to have two ZPTs with a single different line (maintenance problem).

regards
Andre

Jean-Francois.Doyon at CCRS.NRCan.gc.ca wrote:

>Yes, use the "exists:" TAL expression.  So you would do:
>
><span tal:condition="exists: here/request/results" />
>
>or something like that ...
>
>More info in the ZPT reference ...
>
>J.F.
>
>-----Original Message-----
>From: zope-bounces at zope.org [mailto:zope-bounces at zope.org]On Behalf Of
>Andre Meyer
>Sent: Monday, March 15, 2004 5:41 AM
>To: Zope List
>Subject: [Zope] hasattr in tal:condition
>
>
>Dear Zopers
>
>Is it the case that it is not possible to make use of hasattr within a 
>tal:condition statement? In a ZPT I need to test whether an attribute of 
>here/request is set or not. Unfortunately, this raises an exception, 
>which is exactly what I want to prevent...
>
>Here is what the test looks like:
>
>    <span tal:condition="python:test(hasattr(request, results), 1, 
>0)">span</span>
>
>Is there a better way to achieve the same?
>
>thanks and regards
>Andre
>
>PS in the full version the statement looks as follows:
>
>    <body tal:define="results python:test(hasattr(request, results), 
>request.results, here.Catalog()); ... >
>
>
>
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