Reference

A Reference points at something in the graph instead of holding a value: an output of another operator, an input or output of the graph, or a parameter. It is a button that shows the name of what is chosen, or Select when nothing is. Clicking it opens a list of everything that can be chosen, with a first row that chooses nothing. What the list offers depends on the parameter. Feedback lists the outputs of the chosen data type, and Graph Inputs lists the inputs and parameters of the surrounding graph.

The reference follows the thing it points at. Renaming that thing changes nothing. Deleting it, or the operator or graph it belongs to, clears the reference. When a project is opened and something referenced can no longer be found, the reference is cleared and a warning is written to the log.

A reference can be driven by another reference, which hands over its choice. As a source, it sends the name of what it points at as text. To pick several things at once, an operator uses a Reference List.