24. The Body-with-Account Pattern
The concept of membership, or account, occurs frequently in real world situations. It involves a body (like an organisation, but it may also be more like a service, such as a particular course given by an educational institution) and people that are its members, or, in other words, haven an account with it.
This text describes this pattern in terms of context- and role types that can be used as Aspects in models that apply to concrete situations. This pattern can be thought of as an elaboration of the Guest Pattern.