Dagnabit C0 Coverage Information - RCov

       #

       # Returns a subgraph rooted at a given set of nodes.

       #

       # While you can retrieve all descendants of a node pretty easily (i.e.

       # +node.descendants+), and all links from a node really easily (i.e.

       # +node.links_as_ancestor), it's not quite as straightforward to get the

       # nodes and edges (direct edges, that is) out of a graph.

       #

       # The subgraph is returned as an object with two properties: +nodes+ and

       # +edges+.  Both properties are instances of the Set class.

       # 

       # == Examples

       #

       # In the following examples, the node class is called +Node+.  Variables

       # of the form +nM+, where M is an integer, denote Node instances.

       # 

       # Retrieve all descendants of n1 and all direct edges "underneath" n1

       # (i.e. n1 to its children and direct edges for each of n1's

       # descendants):

       #

       # <pre>

       # Node.subgraph_from(n1)

       #

       # => #<Graph nodes=... edges=...>

       # </pre>

       # 

       # Same as above, but builds a graph using n1 and n2 as roots.

       #

       # <pre>

       # Node.subgraph_from(n1, n2)

       # </pre>

       #

       # == Usage tip

       #

       # +subgraph_from+ forces loading of the +descendants+ and

       # +links_as_parent+ +links_as_parent+ associations on Node.  In some

       # situations, you may experience better performance if you use

       # ActiveRecord's eager-loading capabilities when using subgraph_from:

       #

       # <pre>

       # roots = Node.find(..., :include => [:descendants, :links_as_parent])

       # Node.subgraph_from(roots)

       # </pre>

       #

         end

       end

         end

       end

         end

       end

     end

   end

 end