document.write('
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document.write('# constants
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document.write('OFF = false; ON = true
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document.write('# ok, I\'m laaaazy, so I type this just once
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document.write('module Named
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document.write(' attr_accessor :name # getter + setter
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document.write(' def initialize(name)
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document.write(' @name=name
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document.write(' end
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document.write('end
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document.write('
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document.write('# gosh, a switch! this one emits a signal labeld :switched
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document.write('class SignalingSwitch
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document.write(' include Named
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document.write(' include Signaling
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document.write(' def switch
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document.write(' print @name," switched\n"
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document.write(' emit :switched
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document.write(' end
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document.write('end
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document.write('
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document.write('# something to switch.. a light!
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document.write('class Light
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document.write(' include Named
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document.write(' @state=OFF # initial value
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document.write(' attr_accessor :state # getter + setter
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document.write('
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document.write(' def turn(x=!@state) # default: toggle
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document.write(' @state=x
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document.write(' print \' \',@name,\' turned \',if @state then "on" else "off" end,"\n"
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document.write(' end
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document.write('end
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document.write('
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document.write('# ok, let\'s roll. two lights
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document.write('l1 = Light.new("Light1")
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document.write('l2 = Light.new("Light2")
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document.write('
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document.write('# each light gets its own switch
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document.write('s1 = SignalingSwitch.new("Switch1")
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document.write('connect(s1,:switched,l1,:turn)
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document.write('s2 = SignalingSwitch.new("Switch2")
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document.write('connect(s2,:switched,l2,:turn)
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document.write('
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document.write('s1.switch
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document.write('s1.switch
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document.write('s2.switch
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document.write('
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document.write('Switch1 switched
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document.write(' Light1 turned on
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document.write('Switch1 switched
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document.write(' Light1 turned off
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document.write('Switch2 switched
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document.write(' Light2 turned on
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document.write('
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document.write('# add an all of all on switch as well
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document.write('sOff = SignalingSwitch.new("Switch all off")
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document.write('connect(sOff,:switched,l1,:turn,OFF)
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document.write('connect(sOff,:switched,l2,:turn,OFF)
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document.write('sOn = SignalingSwitch.new("Switch all on")
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document.write('connect(sOn,:switched,l1,:turn,ON)
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document.write('connect(sOn,:switched,l2,:turn,ON)
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document.write('
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document.write('sOn.switch
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document.write('sOff.switch
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document.write('
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document.write('Switch all on switched
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document.write(' Light1 turned on
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document.write(' Light2 turned on
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document.write('Switch all off switched
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document.write(' Light1 turned off
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document.write(' Light2 turned off
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document.write('
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document.write('# Another Signals + Slots Implementation for Ruby (c) Axel Plinge 2006
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document.write('
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document.write('# in order to avoid eval(...) cascades, all signaling Objects
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document.write('# have to \'include Signaling\' in order to be able to \'emit\'
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document.write('module Signaling
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document.write(' # connect one of our signals to one someones slot i.e. method
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document.write(' def connect(signal,recipient,slot,*args)
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document.write(' @connections = Hash.new unless @connections
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document.write(' @connections[signal] = [] unless @connections[signal]
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document.write(' @connections[signal].push [recipient.method(slot),args]
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document.write(' end
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document.write('
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document.write(' # emit :signal name => call associated method with args or default value
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document.write(' def emit(name,*args)
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document.write(' return if !@connections
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document.write(' connected_slots =@connections[name]
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document.write(' return if !connected_slots
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document.write(' connected_slots.each do |slot|
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document.write(' slot[0].call(*(slot[1]+args)) # concatenate *args lists
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document.write(' end
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document.write(' end
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document.write('end
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document.write('
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document.write('# connect sender\'s signal to one recipient\'s slot i.e. method
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document.write('# called by sender.emit signal,*emit_args
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document.write('#
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document.write('# if *args are given, recipient.slot(*args,*emit_args) will be invoked,
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document.write('# otherwise the just the args from after the emit statement are used
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document.write('# recipient.slot(*emit_args)
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document.write('def connect(sender,signal,recipient,slot,*args)
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document.write(' sender.connect(signal,recipient,slot,*args)
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document.write('end
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document.write('
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document.write('Modules in Ruby can be used as namespaces in C++ or Java or, as I have done here, for multiple ineritance, just as interfaces are used in Java. Object.method(mehtod_name) gives and Method object with a method call to involke it. Since variable argument lists are arrays, we can concatenate them with + like any other array before unfolding them with *. ');
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