[Zope] TALs difficulties

[Johan Carlsson]

Jim Penny wrote:

> On Wed, 01 Sep 2004 14:45:19 +0200
> Johan Carlsson <johanc at easypublisher.com> wrote:
> 
> 
>>Hi,
>>I need help :-)
>>
>>I'm trying to implement a new Widget for Archetypes.
>>So I have to write TAL (not my favorite hobby).
>>
>>
>>Here's what I've settled for so far:
>>vocab is the DisplayList derivative (item is a key).
>>
>><tal:loop repeat="item vocab">
>>     <optgroup
>>         tal:attributes="label python:vocab.getValue(item);"
>>         tal:condition="python:vocab.isLabel(item)">
>>         </optgroup>
>>     <option selected=""
>>         tal:condition="not:python:vocab.isLabel(item)"
>>         tal:attributes="value item;
>>         selected python:test(here.unicodeTestIn(item, value), 	
>>         
>>'selected', None);"
>>         tal:content="python: vocab.getValue(item)"/>
>></tal:loop>
> 
> 
> This is a simple neting mistake, try:
>  <tal:loop repeat="item vocab">
>       <optgroup
>           tal:attributes="label python:vocab.getValue(item);"
>           tal:condition="python:vocab.isLabel(item)">
>          <option selected=""
>             tal:condition="not:python:vocab.isLabel(item)"
>             tal:attributes="value item;
>             selected python:test(here.unicodeTestIn(item, value),       
>  '          selected', None);"
>             tal:content="python: vocab.getValue(item)"/>
>       </optgroup>
>  </tal:loop>

No. That would only return the <optgroup> because <option> is
dependant on the optgroups condition (and it's condition is the
negation of that so it will never appear).


> Though, as a matter of taste, I don't like this approach, I suspect that
> it will be hard to maintain, as it depends on whatever is generating
> vocab to deliver values in a sorted order.  To me it would be much more
> natural to use a nested loop paramterized on the label value to generate
> the options.

I agree. Also it's probably the only way to do it with TAL.

Actually it's kind of good because this way TAL forces me to write 
better logic.

The problem is that with the Archetypes DisplayList this gets
really complicated to achieve. Not a TAL bad rather an Archetypes
inflexibilty.

Regards,
Johan Carlsson