lib/graph.njae/graph.rb

   1 require 'ostruct'
   2
   3 # A simple graph library
   4
   5 module GraphNjae
   6
   7   # A container for all the parts of a graph.  The graph can have arbitrary attributes,
   8   # treated as method names.
   9   class Graph < OpenStruct
  10     def initialize(values = {})
  11       super(values)
  12       self.edges = Array.new
  13       self.vertices = Array.new
  14       self
  15     end
  16
  17     # Add a Vertex or Edge to the graph.
  18     def <<(other)
  19       if other.class.ancestors.include? Vertex
  20         self.vertices << other
  21       elsif other.class.ancestors.include? Edge
  22         self.edges << other
  23       end
  24       self
  25     end
  26
  27     # Form a product graph of this graph and the other.
  28     # Return the new graph.
  29     def product(other)
  30       product_graph = Graph.new
  31       self.vertices.each do |v1|
  32         other.vertices.each do |v2|
  33           product_vertex = Vertex.new
  34           product_vertex.left_node = v1
  35           product_vertex.right_node = v2
  36           product_graph << product_vertex
  37         end
  38       end
  39     end
  40
  41   end # class
  42 end