[Zope] Building a list programmatically under DTML

[Rik Hoekstra]

> -----Original Message-----
> From: stoermer@migserv.augsburg.mig.net
> [mailto:stoermer@migserv.augsburg.mig.net]On Behalf Of Heiko Stoermer
> Sent: Tuesday, September 07, 1999 10:01 AM
> To: Timothy Grant; Zope Mailing List
> Subject: Re: [Zope] Building a list programmatically under DTML
>
>
> Timothy Grant wrote:
>
> > Hi,
> >
> > I'm working on a project where I need to build a list programmatically
> >
> > I have tried a number of variations of the following without much
> > success. Once the list has been built, I need to pass it on to the next
> > page:
> >
> > <dtml-call "REQUEST.set('idx', 0)">
> > <dtml-call "REQUEST.set('desc', [])">
> > <dtml-call "REQUEST.set('desc_qty', [])">
> >  .
> > .
> >  .
> > <td>
> >   <dtml-var expr="_[Category]">
> >   <dtml-if "_[Category][0:2] <> 'No'">
> >     <dtml-call "REQUEST.set('desc[&dtml-idx;]', _[Category])">
> >     <dtml-call "REQUEST.set('desc_qty[&dtml-idx;]', qty)">
> >     <dtml-call "REQUEST.set('idx', idx + 1)">
> >   </dtml-if>
> > </td>
> >
> > All help would be greatly appreciated!
> >
> >
> >
>
> Hi Timothy,
> first of all: I can't give you a solution...   :-(
> But maybe I can give you a hint, because I had a similar problem the other
> day.
> Unlike PERL, python does not allow you to populate a list by indexing
> slots that are not populated yet. So the following code:
> >>>lst = []
> >>>lst[10] = 'foo'
> will give you the following error:
> >>>IndexError: list assignment index out of range
> But as I can see from your code above, that's exactly what you would like
> to do, and I doubt that DTML-lists behave any different than python
> lists...
> Maybe you should switch to an External Method that gives you access to the
> list object's "append()" method, which allows you to expand an existing
> (empty) list.
>

Just a short reply. As far as I know you can use append in dtml as well. For
example

<dtml-call expr="REQUEST.set('somevar', [])">
<dtml-call expr="somevar.append('somevalue')">

Rik