activate: Determine the context of subsequent manipulations
Description
As a tbl_graph can be considered as a collection of two linked tables it is
necessary to specify which table is referenced during manipulations. The
activate verb does just that and needs affects all subsequent manipulations
until a new table is activated. active is a simple query function to get
the currently acitve context.
Usage
activate(.data, what)
active(x)
Arguments
.data, x
A tbl_graph or a grouped_tbl_graph
what
What should get activated? Possible values are nodes or
edges.