Invisibly call methods on all array members

invisible_proxy_to_array.rb

# The invisible proxy allows seamless calling of a method on all objects of an array.
# When an array is wrapped (passed into) one of these objects, you can call a function
# on all objects in the array with one line. Useful for dsl's and such.

class InvisibleProxyToArray

  instance_methods.each do |m|
    undef_method(m) unless m =~ /(^__|^nil\\?|object_id|^send)/
  end
  
  def initialize(collection)
    @collection = collection
  end

  def respond_to?(symbol)
    @collection.first.respond_to?(symbol)
  end
   
  # calls a method on every member of the proxied array
  # and totals the return values
  def total(total_symbol)
    @collection.inject(0){|tot, obj| tot + obj.send(total_symbol)}
  end
    
  # gives a string indicating object responses to being sent a symbol (which calls a property or method)
  # summarize(:status) will produce:  running (2), stopping (13)
  def summarize(summarize_symbol)
    msgs=[]
    hsh=hash_by_result(summarize_symbol, @collection)
    hsh.each {|status, resources_arr| msgs << "#{status}: #{resources_arr.length}"}
    msgs.join(', ')
  end
  
  # returns a hash like {"running"=>[a , b], "dead"=>[a]} for :status or other messages
  # where a and b would be resources whose response for :status was "running"
  def hash_by_result(property_symbol, object_array)
    hsh={}
    object_array.each do |obj|
      val = obj.send(property_symbol)
      hsh[val] ||= []
      hsh[val] << obj 
    end
    hsh
  end
   
  private

  def method_missing(method, *args, &block)
    @collection.each {|item| item.send(method, *args, &block)}
  end
  
end

# a toy to demonstrate 
class Thing
  attr_reader  :value
  
  def initialize(value)
    @value=value
  end
  
  def say_num
    puts "My value is: #{@value}"
  end  
  
  def status
    ['pillow talk, baby','chewing bubblegum', 'kicking ass'].sample
  end
  
end

mythings=InvisibleProxyToArray.new([Thing.new(9), Thing.new(10), Thing.new(9), Thing.new(11)])
puts "total: #{mythings.total(:value)}"
puts "summarize: #{mythings.summarize(:status)}"
puts "the fun part--call a method on all members with one line and no block"
mythings.say_num