Step extension

A step extension specifies an alternative behavior that may follow a step. The enabling condition of a step extension is specified as follow:

delay_specification [condition_statement], or

condition

The enabling condition of a step extension may be

• a before delay,
• an after delay,
• a condition,
• a combination of before and after delays, or
• a combination of before, after delays and a condition.

A step extension specifies a sequence of extension actions. Each extension action may be a concept operation instance, a branching statement or a reference to an included use case.