KamilLelonek

class RandomStringGenerator
  def without_numbers(length)
    random_string(length, alphabet)
  end

  def with_numbers(length)
    random_string(length, alphabet + numbers)
  end

  private

KamilLelonek

class SandwichMaker
  def make_me_a_sandwich
    puts 'OKAY'
  end
end

KamilLelonek

➜  ~  pry
[1] (pry) main: 0> a = [1, 2, 3]
=> [1, 2, 3]
[2] (pry) main: 0> a.count
=> 3
[3] (pry) main: 0> a.size
=> 3
[4] (pry) main: 0> a.length
=> 3

KamilLelonek

class LazyEmployee
  def initialize(sandwich_maker)
    @sandwich_maker = sandwich_maker
  end
  
  def make_me_a_sandwich
    sandwich_maker.make_me_a_sandwich
  end
  
  private

KamilLelonek

class LazyEmployee
  def initialize(sandwich_maker)
    @sandwich_maker = sandwich_maker
  end
  
  def method_missing(method, *args)
    if sandwich_maker.respond_to?(method)
      sandwich_maker.send(method, *args)
    else
      super

KamilLelonek

require 'forwardable'

class LazyEmployee
  extend Forwardable
  
  def initialize(sandwich_maker)
    @sandwich_maker = sandwich_maker
  end
  
  def_delegators :@sandwich_maker, :make_me_a_sandwich

KamilLelonek

require 'active_support/core_ext/module/delegation'

class LazyEmployee
  def initialize(sandwich_maker)
    @sandwich_maker = sandwich_maker
  end
  
  delegate :make_me_a_sandwich, to: :sandwich_maker
  
  private

KamilLelonek

class LazyEmployee < SimpleDelegator
  def initialize(sandwich_maker)
    super
  end
end

KamilLelonek

[1] (pry) main: 0> add = -> (a, b) { a + b }
=> #<Proc:0x007ffde11d72c0@(pry):1 (lambda)>

# Call proc with two arguments
[2] (pry) main: 0> add.(1, 2)
=> 3

# Call proc with one argument
[3] (pry) main: 0> add.(1)
ArgumentError: wrong number of arguments (1 for 2)

KamilLelonek

[1] (pry) main: 0> l = lambda { puts "I'm in lambda" }
=> #<Proc:0x007ffde32af6f0@(pry):9 (lambda)>

[2] (pry) main: 0> l.call
"I'm in lambda"
=> nil

[3] (pry) main: 0> l = -> name { puts "Hi #{name}!" }
=> #<Proc:0x007ffde3312840@(pry):14 (lambda)>