[ZDP] BackTalk to Document The Zope Book (2.5 Edition)/Advanced Page Templates

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A comment to the paragraph below was recently added via http://www.zope.org/Documentation/Books/ZopeBook/current/AdvZPT.stx#4-138

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        The 'test' function works like an if/then/else statement. See
        Appendix A, "DTML Reference" for more information on the
        'test' function. Here's another example of how you can use the
        'test' function::

          <tr tal:define="oddrow repeat/item/odd"
              tal:attributes="class python:test(oddrow, 'oddclass',
                                                'evenclass')">

          % Anonymous User - Apr. 18, 2002 12:43 pm:
           It's easy to understand the objective, but the example is cryptic, could you 
           add a bit of code?

          % Anonymous User - June 11, 2002 3:07 am:
           My problem with this is that i use the <tr> tag for tal:repeat, and it doesn't seem to recognise the
           repeat/item/* within the same <tr> tag context. If you don't use the <tr> to repeat rows of a table, what do
           you use? Every other tag is technically illegal inside a table, but outside <tr> tags. I know that the
           rendered html won't show them if you use omit-tag, or whatever, but it seems a crappy solution to build
           invalid html wrappers, when the point of page templates is to be 100% valid HTML. So the only option i can
           find is to put that clunky code into every <td> tag within the <tr>... which is ugly, and also slow. So it
           seems the duplicate <tr> is the only method I can see which one can alternate classes, and maintain valid
           HTML in their zpt files.

          % Anonymous User - July 17, 2002 6:34 am:
           An complete example would be:

           <table>
             <tr tal:attributes="class python:test(path('repeat/item/odd','odd','even')"
                 tal:repeat="item container/objectValues">
               <td tal:content="item/title_or_id">Some title</td>
             </tr>
           </table>

           with eg as CSS:

           .even { background-color: gray; }
           .odd { background-color: yellow; }

           It gets ride of the 'tal:define'. The usage of 'path()' is explained in the next section.

          % Anonymous User - July 18, 2002 8:31 am:
           <tr tal:attributes="class python:test(path('repeat/item/odd','odd','even')"
                                            ^    ^
           should be
           <tr tal:attributes="class python:path(test('repeat/item/odd','odd','even')"

          % Anonymous User - July 20, 2002 7:05 am:
           i think we're still missing a closing bracket...

          % Anonymous User - Oct. 7, 2002 3:37 am:
           actually the first line of the first line should look like this:
           <tr tal:attributes="class python:path(test(path('repeat/item/odd'),'string:odd','string:even'))"

           but as i don't drink that much i feel betta with this:
           <tr tal:attributes="class python:test(repeat['item'].odd(),'odd','even')"

           or, when code might be read by others, this:

           <table>
             <tr tal:attributes="class python:repeat['item'].odd() and 'odd' or 'even'"
                 tal:repeat="item container/objectValues">
               <td tal:content="item/title_or_id">Some title</td>
             </tr>
           </table>