Invalidate-argument

invalidate-argument
    Invalidate-argument (Conditional operator)
    Removes an argument from future consideration as a special data item.
    Takes 1 or more arguments...
    All: The argument to remove from the preceding argument list.

Comments

Using this is required if you intend to cycle through a list of non-recurring arguments in an event based on conditionals featuring arguments, like every-time-argument and when-argument. Otherwise, an argument remains valid even after it has been used once.

In earlier versions of FreeSpace Open, the default value used to be <any data>. In current versions, it's <argument>.