about =
"This demonstration shows operator overloading in
Ruby. It uses the standard mean time between failure
calculation to compute the reduced service interval
when two components each with at attention span is
added together, and overloads the '+' operator to
perform the action.

Example by Graham Ellis of Well House Consultants
Yes, we offer Ruby training - http://www.wellho.net/
or email graham@wellho.net. Public and Private courses

" # Note 6

# See training notes for full details of each of
# the notes in this example

class Compo
   def initialize(name,hours)
      if name.instance_of?(Array) # Note 1
         @name = name
      else
         @name = [name]
      end
      @hours = hours
   end
   def gethours
      return @hours
   end
   def getname
      repst = ""
      (0...@name.length).each do |k| # Note 2
          repst += sprintf("%3d. %s\n", # Note 3
                k+1, @name[k])
      end
      return repst
   end
   def getnamearr
      return @name
   end
   def + (second)
      tempname = @name + second.getnamearr
      newhours = 1.0 / (1.0 / @hours + 1.0 / second.gethours)
                        # Note 7
      linked = Compo.new(tempname,newhours)
      return linked
   end
end

if __FILE__ == $0 # Note 4
    puts about
    coffeemachine = []
    coffeemachine.push(Compo.new("fill with water",5))
    coffeemachine.push(Compo.new("fill with beans",10))
    coffeemachine.push(Compo.new("empty grounds",8))
    coffeemachine.push(Compo.new("empty spill",7))

    actions = Compo.new("Thorough Clean",30)
    coffeemachine.each do |job|
        actions = actions + job # Note 5
    end

    schedule = actions.getname
    frequency = sprintf("%.2f",actions.gethours)

    print "The actions are \n#{schedule}"
    print "The average attention interval is #{frequency} hours\n"

    end