In MDriven, we want to change data when appropriate – so we use the same syntax as OCL in something we call EAL – ExtendedActionLanguage.

We use EAL in MDriven here:

• Action execute expression
• Actions in ViewModel columns Execute expression
• Class method implementations
• StateMachine Effects

EAL Differences

When using EAL, one often wants to stack expressions after each other. To allow for this, EAL has introduced an expression separator: The semicolon ;. This means that you can build method bodies that do several things like this:

 self.SomeDateTime := DateTime.Now;
 self.SomeInt := 27;
 self.SomeString := self.SomeDateTime.ToString('yyyy-MM-dd')

In EAL, we use := to assign but = to compare.

In EAL, we can also create new objects Thing.Create

Worth noting is that the expression separator ; can only be used between statements. So writing this ‘a string’;0 is of type integer. But writing this ‘a string’;0; is of unknown type and hence wrong – the last statement that the parser expects after the last ; is not found.