[Zope] Re: [ZPT] Recursive structures

[Nikko Wolf]

Ian Bicking wrote:

> I'm surprised this has never come up for me before, but now I want to 
> render a recursive data structure and I'm at a loss how I might do 
> that in ZPT.  Or, what the best workaround would be.  E.g.:
>
> ['a', 'b', ['c', ['d', 'e']]]
>
> Becomes:
>
> <ul>
>  <li>a</li>
>  <li>b</li>
>  <ul>
>   <li>c</li>
>   <ul>
>    <li>d</li>
>    <li>e</li>
>   </ul>
>  </ul>
> </ul>
>
>
> I guess the template could call itself repeatedly.  Which means the 
> list can't be embedded in any other markup.  Hrm... in Cheetah I'd do:
>
> #def make_list(items)
> <ul>
>  #for item in items
>   #if isinstance(item, list)
>    $make_list(item)
>   #else
>    <li>$item</li>
>   #end if
>  #end for
> </ul>
> #end def
> $make_list(items)
>
> It's a code-heavy template, and maybe it should just be written in 
> Python, but it's also reasonable to allow people to add classes to 
> items, further logic, etc.
>
I think it should *definitely* be written in Python, although a "Script 
(Python)" should suffice.  Add a "Script (Python)" with an ID of 
"make_list" and a parameter list of "items"   The following is untested, 
but should work, I think.     Beware of any special text in the strings 
(&,<,>,etc).
 
######
text = "<ul>\n"
for item in items:
   if isinstance( item, ( list, tuple )):
       text += context.make_list( item )
   else:
      text += "<li>" + str(item) + "</li>\n"
return text + "</ul>"
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