[Zope] TALs difficulties

[Paul Winkler]

On Wed, Sep 01, 2004 at 04:38:30PM +0200, Johan Carlsson wrote:
> 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.

So, maybe write a Script that does some processing of
the DisplayList and gives you something more reasonable.
I gather that iterating over vocab and doing getValue() on each
gives you something like:

['A', 'Ada', 'Ape', 'B', 'Banana', 'Buffy', ...]

So, write a script that does something like (untested):

items = {}
raw = [vocab.getValue(item) for item in vocab]
for s in raw:
    if vocab.isLabel(s):
        items[s].setdefault([])
    else:
        items[s[0]].append(s)
result = [{'label': k, 'values': v) for k, v in items]
return result



Then you should have something like this:

[{'label: 'A', 'values': ('Ada', 'Ape')},
 {'label: 'B', 'values': ('Banana', 'Buffy')},
 ... ]


Plugging this in to your template should then be easy.
Something like:

<tal:loop repeat="group myScript">
     <optgroup
         tal:attributes="label group/label"
        <tal:loop repeat="item group/values">
        <option selected=""
           tal:attributes="value item;
           selected python:test(here.unicodeTestIn(item, value),       
           '        selected', None);"
           tal:content="item" />
        </tal:loop>
     </optgroup>
</tal:loop>

... except that I goofed up unicodeTestIn which apparently
expects the original item from your vocab as an argument.
Well, stuff that in your data structure somewhere too :-)

-- 

Paul Winkler
http://www.slinkp.com