Structure of an activity

To relate syntax to semantics, it is best to visualize an xUML activity as a data flow diagram (see the Model Semantics section). Each bubble on the data flow diagram corresponds to a Scrall action in text. We can then consider the data/control inputs and outputs (arrows in and out) defined for that action. That’s certainly not a formal definition and, absent a proper action language metamodel, it’s about the best we can do for now.

We’ll dig a bit deeper to see how Scrall text elements correlate with graphical data flow diagram symbols.

Action block

Statement

Single line action

Multiple dependent actions on a single line

Multiple independent actions on a single line

An action spread across multiple lines

A conditional group of single line actions

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