[PHPTAL] Conditional Attribute Output

[Werner]

Hi!

I'm having lots of trouble to evaluate conditions inside tal:attributes 
statements.

Is it even possible to use conditional expressions inside tal:attributes 
statements?

For example, it would be really convenient to only output certain HTML 
attributes for an element is certain conditions are met.  Consider this 
common scenario: You only want to add 'class="last"' to an '<li>' tiem 
that is created by using tal:repeat. It's easy to output an unordered 
'<ul>' list from a PHP array, but what if you want the last array item 
(repeat/item/end) to set a certain class attribute to the last '<li>' item?

So, if you have an array like this...

$arr = array('One', 'Two', 'Three');

and you want this output...

<ul>
    <li class="first">One</li>
    <li>Two</li>
    <li class="last">Three</li>
</ul>

It becomes very difficult, because (and this is the only way I know how 
to solve this problem) you have to wrap the LI output in lots of 
conditional span tags (with tal:omit-tag) like this:

<ul tal:condition="exists: arr">
    <span tal:repeat="item arr" tal:omit-tag="">
        <li tal:condition="repeat/item/start" class="first">
        <li tal:condition="repeat/item/end" class="last">
    </span>
    etc...
</ul>


*Please* tell met if there is any way to do something like this (my 
imaginary syntax is off course invalid):

<li tal:attributes="class condition:repeat/item/start first; class 
condition:repeat/item/end last">


Secondly, please tell me where I can find examples of tal:condition 
statements that contain the GT and LT operators - there are not any 
examples in the manual as far as I can see?

Thanks for your time and efforts,
Werner