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In-Sequence (Conditional operator) Supplies arguments for the <argument> special data item. The first argument in the list will be selected to satisfy the expression(s) in which <argument> is used. The same argument will be returned by all subsequent calls Takes 1 or more arguments... All: Anything that could be used in place of <argument>.
One of the possible uses of this SEXP is to gradually beam-free a warship, like this:
$Formula: ( when-argument ( in-sequence "turret20" "turret22" ) ( true ) ( beam-free "Phoenicia" "<argument>" ) ( invalidate-argument "<argument>" ) ) +Name: Phoenicia beams +Repeat Count: -1 +Trigger Count: 2 +Interval: 5
(where Phoenicia is a GTD Hecate and the turrets above are her upper and lower forward main beam cannons, respectively.)