lib/graph.njae/vertex.rb

   1 require 'ostruct'
   2
   3 # A simple graph library
   4
   5 module GraphNjae
   6   # A vertex in a graph. The edge can have arbitrary attributes,treated as
   7   # method names.
   8   class Vertex < OpenStruct
   9     def initialize(values = {})
  10       super(values)
  11       self.edges = []
  12       self
  13     end
  14
  15     # Connect this vertex to another, creating an Edge to do so, and returning
  16     # the Edge
  17     def connect(other)
  18       e = Edge.new
  19       e << self << other
  20       # self.edges << e
  21       # other.edges << e unless self === other
  22       e
  23     end
  24
  25     # Connect this vertex to another, creating an Edge to do so, and returning
  26     # this Vertex
  27     def <<(other)
  28       connect(other)
  29       self
  30     end
  31
  32     # Return the set of neighbouring vertices
  33     def neighbours
  34       #vertices = self.edges.map {|e| e.vertices}.flatten
  35       #vertices_to_me = vertices.select {|v| v == self}
  36       #other_vertices = vertices.select {|v| v != self}
  37       #(vertices_to_me[1..-1] || []) + other_vertices#
  38       self.edges.map {|e| e.vertices.take_while {|v| v != self} +
  39                       e.vertices.drop_while {|v| v != self}[1..-1]}.flatten
  40     end
  41
  42   end
  43 end