Ruby 2.0 features examples

lazy-1.rb

elements = (1..19999999)

p elements.class # => Range

results = elements.select { |n|
  n % 2 == 0
}.map { |n|
  n + 1
}.take(10)

p results # => [3, 5, 7, 9, 11, 13, 15, 17, 19, 21]

# ruby 2.72s user 0.10s system 99% cpu 2.822 total

lazy-2.rb

elements = (1..19999999).lazy

p elements.class # => Enumerator::Lazy

results = elements.select { |n|
  n % 2 == 0
}.map { |n|
  n + 1
}.take(10)

p results.force # => [3, 5, 7, 9, 11, 13, 15, 17, 19, 21]

# ruby 0.04s user 0.04s system 96% cpu 0.087 total

prepend-1.rb

module FooBar
  def say
    puts "2 - Module"
    super
  end
end

class Foo
  def say
    puts "3 - Parent Class"
  end
end

class Bar < Foo
  include FooBar

  def say
    puts "1 - Implementing Class"
    super
  end
end

Bar.new.say # =>
            # 1 - Implementing Class
            # 2 - Module
            # 3 - Parent Class

prepend-2.rb

module FooBar
  def say
    puts "2 - Module"
    super
  end
end

class Foo
  def say
    puts "3 - Parent Class"
  end
end

class Bar < Foo
  prepend FooBar

  def say
    puts "1 - Implementing Class"
    super
  end
end

Bar.new.say # =>
            # 2 - Module
            # 1 - Implementing Class
            # 3 - Parent Class

refinements-1.rb

class String
  def to_s
    self + "......"
  end
end

puts "No periods".to_s # => "No periods......"

refinements-2.rb

module MonkeyPatch
  refine String do
    def to_s
      self + "......"
    end
  end
end

puts "No periods".to_s # => "No periods"

class SomeController
  using MonkeyPatch

  puts "No periods".to_s # => "No periods......"
end

puts "No periods".to_s # => "No periods"