UML23 — Semantics of the AddVariableValueAction

In the Semantics of the AddVariableValueAction there is a line stating: "If isReplaceAll is false and the variable is unordered and non-unique, then adding an existing value has no effect." I find this statement in correct and in conflict with the semantics defined in multiplicity element. multiplicityElement.ordered -> Specifies whether the values are inserted in a certain position which can be identified by an Integer. This has no influence whatsoever on WHAT values can be added to a variable. multiplicityElement.unique -> An instance (of any type) cannot appear more than once in the collection of values. addVariableValueAction.isReplaceAll -> Specifies if all the previous values are removed before inserting the new ones. This does have influence on WHAT values can be added to a variable. Therefore if the addVariableValueAction is true then the input collection only needs to be evaluated. Else the input collection and the existing values need to be cheked. If the variable IS unique then it must be ensured that the add operation does not put the same instance more than once in the variable. This means that input collection will be merged with the existing values collection (empty collection if isReplaceAll==true) and then the repeated isntances will be removed. If the variable IS NOT unique then there is no need to check anything. Having repeated values in an unordered collection might have sense, for example to execute an algorithm to retrieve the number of times a user has logged in.

duplicate of issue # 8972