Respond To Missing

meta.rb

class Person
  def initialize(name)
    @name = name
  end

  def small_talk(other)
    greet(other)

    topics = methods.grep /^chat_about_/
    topics.shuffle!
    topics.each{ |topic| self.send topic }
  end

  def greet(other)
    puts "Hi #{other}, I'm #{@name}"
  end

  def chat_about_weather
    puts "Hmm.. storm's a coming."
  end

  def chat_about_sports
    puts "Did you see the game last night?"
  end

  def chat_about_movies
    puts "Seen any good movies lately?"
  end

  def to_s
    @name
  end

  CHAT_METHOD_REGEXP = /^chat_about_(.+)/

  def method_missing(name, *arguments)
    if name =~ CHAT_METHOD_REGEXP
      puts "I don't really know much about #{$1}."
    else
      super
    end
  end

  def respond_to_missing?(name)
    name =~ CHAT_METHOD_REGEXP || super
  end
end

class CollectionProxy
  include Enumerable

  def initialize(collection)
    @collection = collection
  end

  def each(&block)
    @collection.each(&block)
  end

  def to_a
    @collection
  end

  def inspect
    details = @collection.inspect
    "#<CollectionProxy>: #{details} >"
  end

  def method_missing(name, *arguments)
    mapped_items = @collection.map{ |item| item.send(name, *arguments) }
    CollectionProxy.new(mapped_items)
  end

  def respond_to_missing?(name)
    @collection.all?{ |item| item.respond_to? name }
  end
end

colors = CollectionProxy.new(%w(red green blue))
p colors.upcase.reverse

numbers = CollectionProxy.new([2, 3, 4])
p numbers + 2
p (numbers + 2).inject(:+)