Referring to the current output in a map rule

A map rule can include the name of the output object to which it applies. For example, to use the INDEX function on LineItem, the map rule on LineItem will include LineItem. Instead of using the entire object name for LineItem, use the dollar sign shorthand symbol $. The dollar sign $ refers to the object to which the expression applies.

A map rule can also reference other output objects that appear above the map rule.

In the functional map, you can create an additional input card to represent the index of the desired item. This is one case in which the type of an input card in a functional map has been chosen from the output. In fact, any numeric item may be chosen for that card's type.