26.2. The pattern
A context that wants to offer an end user the opportunity to explore a context without committing to it, may introduce a calculated role like so:
User Guest = sys:Me
Perspective on CommittedRole
only (Create, Fill)
Where CommittedRole is the role that brings commitment and requirements with it.
An end user first visits the context and assumes the Guest role (the outcome of the algorithm given above). He then creates an instance of CommittedRole and fills it with himself. From that moment, the algorithm no longer returns the type of Guest, but that of CommittedRole. His perspectives change accordingly.