[Zope] TAL: test() or condition Howto?

[Elena Schulz]

Hi,

I have the followong TAL-expression:

    <td
    tal:content="structure python:here.test(myImportantCondition and
myExpensiveMethod(), myExpensiveMethod(),
'myDefaultString')">myDefaultString</td>

To execute 'myExpensiveMethod()' 'myImportantCondition' must be 'true'. But
I want to avoid to execute 'myExpensiveMethod()' two times. How can I achive
that? As default-value myDefaultString should be served.

I don't know a way with tal:condition 'cause on 'false' there is no way to
get 'myDefaultString', isn't it?

-- many thanks for your replies, Elena