Control flow

Control concepts

Within a single activity, control defines an explicit order in which actions may execute or supplies a predicate evaluation to decide which actions may execute. A set of one or more actions defined to execute under the same conditions are grouped as an action block. Explicit sequence is determined by setting and using sequence tokens. Conditional activation is established by a traditional if-then-else clause or through the use of boolean scalar variables used as guards.

Flow of control

Control is visualized in a data flow diagram as a dashed line that delivers either a sequence token or a diamond that splits out a true/false result. For our purposes, the dashed line is represented by setting and delivering a sequence token. The decision diamond is handled by either with an if-then-else construct or by setting one or more boolean scalar variables for later reference.