Theoretical Approach

This work is based on GUIMeta abstract syntax (Figure 1) and semantics for use case. Since some aspects of the abstract syntax were not implemented and some aspects of semantics were reinterpreted by us, the implemented metamodel has his abstract syntax represented in Figure 2.

The aspects that were not implemented are specify and precede. The first one may involve the rest of the GUIMeta, that involve more than just use case, since GUIMeta is a metamodel for (I forgot the term, I should read the paper again). The second allow the use case to represent steps in a parallel flow. This parallel representation is a very hard thing to represent.

The aspects changed in the abstract syntax are: a new metaclass step, a new relation parent, and Repeating Step is composed of steps.

The metaclass steps is a resolution of the conflict that do not specify if a main flow could has an extension step (since flows aren't determine in this abstract syntax)(and a may flow shouldn't have any extension steps), so creating the metaclass steps we ensure that the alternative flows and extension step are isolated from main flow.

The Repeating Step do not has a precise definition in the original GUIMeta, so we change some aspects of this metaclass to be compatible with our interpretation and the semantic embedded. Following the ideia of a While loop in C, a small flow of events that are repeated until the condition is not satisfied, we add the composition of use case steps to create the flow.

These modification may affected the representation capacity of metamodel, but for now our tests didn't find anything (we still testing it).