An example of using TSort

job_runner.rb

require 'tsort'

class JobRunner
  include TSort
  
  def initialize()
    @jobs = {}
    @jobs.default = []
  end

  alias_method :execute, :tsort
  
  def add(name, dependencies=[])
    @jobs[name] = dependencies
  end
  
  def tsort_each_node(&block)
    @jobs.each_key(&block)
  end
  
  def tsort_each_child(node, &block)
    @jobs[node].each(&block)
  end
end

if __FILE__ == $0
  runner = JobRunner.new
  runner.add('breakfast', ['serve'])
  runner.add('serve', ['cook'])
  runner.add('cook', ['buy eggs','buy bacon'])
  puts runner.execute
end