a group assignment accessor
A group accessor assigns specific nodes a group string. Layering operators that take a group accessor should respect the convention that nodes with the same group should have the same layer.
assign a group to a node
the node to assign a group to
group - the node's group, undefined if the node doesn't have a group
undefined
a group assignment accessor
A group accessor assigns specific nodes a group string. Layering operators that take a group accessor should respect the convention that nodes with the same group should have the same layer.