Question

If I use a variable that hasn’t been put into the scope, PHPTAL throws an exception. Is there any way of making PHPTAL fall back to graceful defaults, for example evaluating to false in a boolean context, to a blank in a string context, etc?

Answer 1

You can add ‘| nothing‘ to TALES expressions or use isset() in php: expressions.

<p tal:attributes='class php:isset(class)?class:NULL'     tal:content='variable | nothing' /> 

If you have larger bit of code that relies on a certain variable, then use exists: modifier:

<div tal:condition='exists:variable'> … </div> 

If you want to fake existence of any variable, it can be done, but I don’t recommend it (it will hide typos):

class FakeAll extends stdClass {     function __get($var){return '';}     function __isset($var){return true;} }  $p = new PHPTAL(); $p->getContext()->setGlobal(new FakeAll());