UML22 — UML 2.1 Spec, Interactions: 14.3.18

I don’t understand why the type of the property ‘InteractionUse.argument’ is Action; I think that there at least needs to be some explanation.

Also, looking at the syntax for ‘InteractionUse’ in the Notation section:

“<name> ::=[<attribute-name> ‘=’ ] [<collaboration-use> ‘.’] <interaction-name> [‘(‘ <io-argument> [‘,’ <io-oargument>]* ‘)’] [‘:’ <return-value> <io-argument> ::= <in-argument> | ‘out’ <out-argument>]

The <attribute-name> refers to an attribute of one of the lifelines in the Interaction.”

How does the reference to the attribute get stored in the model?

Finally in Fig 14.18, I don’t see how the notation for the described InteractionUse can be produced from the syntax above, particularly the first part: “:xx.xc=”

Arguments of InteractionUse shall be ValueSpecifications, as arguments of Message.
Furthermore introduce a couple of extra attributes/associations to cover the information not easily found today.
Finally fix the BNF of the concrete textual syntax by a concluding „]?