All choices have a selection. This is a state representing the items currently selected. The selection is represented as a vector of offsets into the list of the choice's items, unless it is a single-selection choice, in which case it is just represented as an offset.
The initial selection is controlled with the initarg
:selection
. The accessor
choice-selection
is provided.
Generally, it is easier to refer to the selection in terms of the items selected, rather than by offsets, so the CAPI provides the notion of a selected item and the selected items . The first of these is the selected item in a single-selection choice. The second is a list of the selected items in any choice.
The accessors
choice-selected-item
and
choice-selected-items
provide access to these conceptual slots, and you can also supply the values at
make-instance
time via the initargs
:selected-item
and
:selected-items
.