[Zope] Checking sequence-index using dtml-if

[Curtis Maloney]

On Monday 19 February 2001 16:56, John Morton wrote:
> On Sun, 18 Feb 2001 21:57:27 -0600 Jeff Hotz <jeff@hotz.net> wrote:
> > I only want to operate on the first 3 records returned in the
> > ZSQL_select_images.
> >
> > I thought that a dtml-if test would do it based on the dtml-var
> > sequence-index but I'm not having any luck.
> >
> > Any suggestions on either my logic or the implementation of it?
> >
> > Any help you can offer will be greatly appreciated.  Thanks.
> >
> > <dtml-in ZSQL_select_images>
> >    <dtml-if expr="'<dtml-var sequence-index>' < 3">
>
> You can't embed a dtml statement inside another like this .I believe this
> says 'if the string '<dtml-var sequence-index>' is less than three', which
> is not what you want. What you probably did was to start by using
> sequence-index and had zope complain about it. What you should try is
> this:
>
> <dtml-if expr="_['sequence-index'] < 3">
>
> Use the dtml namespace lookup notation when ever you need to use an
> attribute name with a '-' in it, inside an expression. And submit it as a
> bug to the collector until the DC folk give in and include '_' equivalents
> to all the attributes that use dashes :-)
>

Whilst this is a good answer in that it corrects a misunderstanding in the 
users understanding of DTML, there is, imho, a better solution to the actual 
problem.  And that is to slice the returned list from the ZSQL method....  
something like:

<dtml-in expr="ZSQL_select_images()[:3]">
...
</dtml-in>

will only iterate over the first 3 elements in the list.

> John
>
>