[Zope] logical operator in dtml-if

[Matthew Parslow]

I am doing some error checking with <dtml-if>, simply to check that some
variables exist, however I can't seem to find a syntax that ZOPE agrees with to
use AND. 
what I want to do:
<dtml-if Var AND anothervar AND yetanothervar>
render page
<dtml-else>
you have to enter details in all the fields
</dtml-if>
I know this is a messy way to do it, and I'd appreciate all suggestions.
Thanks,
Matthew Parslow