zcml

What are the valid conditions for zcml:condition?

ZCML can include conditional directives of the form <configure zcml:condition="installed some.python.package"> (conditional configuration directives) </configure> What is the expression syntax for condition? Is 'or' allowed? ...

What is the difference between a Zope utility defined with a factory versus a component?

It's a little confusing that ZCML registrations for Zope utilities can accept a component or a factory. <utility component=".some.Class" /> versus <utility factory=".some.Factory" /> What is the difference? ...