CollectionDescription

A collection description is a special type of Collection that defines collection instances to be created in Item instances. Collection members reference ItemDescription, which define the types of Item instances which may fit in the instantiated collection. Dependency descriptions only reference one Item Description, whereas Aggregation descriptions can contain many members, each defining the type of one slot in the Aggregation instance.

Collection Description Instantation

When a collection description is instantiated by the CreateItemFromDescription or CreateAgentFromDecription PredefinedStep, it reads the PropertyDescription outcome in the referenced Item(s) and copies the transitive PropertyDescription into the properties of the newly created collection. This is mechanism is required for the implementation of 'typed' collections.