gml_parser.rb

module GMLParser

  class Graph < Struct.new(
      :nodes,
      :edges
      )
    
    def edge_list
      self.edges.map{|e| [e[:source], e[:target], e[:value]]}
    end
    
  end
  
  class Parser
    def self.parse gml_data
      graph = gml_data.gsub(/\n/, '').scan(rgxp[:graph]).inject([]) do |g, s|
        g << s.scan(rgxp[:node]).map do |n|
          {
            :id    => n.match(rgxp[:id]).captures.first,
            :label => n.match(rgxp[:label]).captures.first
          }
        end
        g << s.scan(rgxp[:edge]).map do |e|
          {
            :source => e.match(rgxp[:source]).captures.first,
            :target => e.match(rgxp[:target]).captures.first,
            :value  => e.match(rgxp[:value]).captures.first
          }
        end
        g
      end
      Graph.new(*graph)
    end
    
    def self.rgxp
      {
        :graph  => /graph.*\[[^\[\]]+\]/,
        :edge   => /edge\W+\[[^\[\]]+\]/,
        :node   => /node\W+\[[^\[\]]+\]/,
        :id     => /id\W+([A-Za-z0-9]+)/,
        :label  => /label\W+([A-Za-z0-9]+)/,
        :source => /source\W+([A-Za-z0-9]+)/,
        :target => /target\W+([A-Za-z0-9]+)/,
        :value  => /value\W+([A-Za-z0-9]+)/      
      }
    end
    
  end
  
end