55.3 Optional nodes

Individual nodes can be marked as optional in a definition by setting the minimum value in the repeat or occurrences section to "0", see repeat / occurrences / optional.

To avoid having to account for certain nodes in definitions at all, create a special definition whose sole purpose is to remove these nodes from the list of nodes to be converted. Set the Handling of matching nodes drowdown to the second entry in the definition. As the first step in converting node sequences, these nodes are removed entirely from the sequence. In the second step, the remaining definitions are applied to the remaining node sequence. This approach is useful for MOVED mouse events on menu items, for example. PRESSED or RELEASED keyboard events that are recorded in addition to the actual keyboard event are also sometimes best filtered out in the first step.