require 'ostruct'
+# A simple graph library
+
module Graph
+
+ # An edge (or multiedge) in a graph. The edge can have arbitrary attributes,
+ # treated as method names.
+ #
+ # Each connection is handled by a Graph::Connection object, so that each end
+ # of the Edge can have it's own attributes.
class Edge < OpenStruct
def initialize
super
self
end
+ # Connect this edge to a vertex
def <<(other)
c = Connection.new
c.end = other
self
end
+ # Return the set of vertices this edge connects.
def vertices
self.connections.map {|c| c.end}
end
+ # Return the connection object that joins this Edge to the specified Vertex
def connection_at(vertex)
self.connections.select {|c| c.end.equal? vertex}.first
end
end
+ # A connection between an Edge and a Vertex.The connection can have arbitrary attributes,
+ # treated as method names.
class Connection < OpenStruct
def initialize
super