[Zope-dev] Getting a list of ZCatalogish objects

Hello, How could I retrieve a list of available ZCatalogish objects? I meant objects in which CatalogAware objects can register themselves. This include ZCatalogs but also custom objects based on ZCatalog. The nearest solution I've found yet is using ZQueryIds(). This method returns ids of searchable objects, which isn't exactly what I'm looking for (Z SQL methods are searchable, aren't they?). Thanks. Alexandre