ngpestelos

x = lambda { "hello again" }
puts x.call

ngpestelos

x = Proc.new { "hello" }
puts x.call

ngpestelos

def hello
  puts "Hello, #{yield}!"
end

hello { "world" }

ngpestelos

# see Metaprogramming Ruby, p. 104

class Book

  def title
    "title"
  end

  def subtitle
    "subtitle"

ngpestelos

# See http://techie.lucaspr.im/creating-class-macros/

class MyClass
  def self.create_hello_method_for(name)
    define_method(:hello) do
      puts "Hello #{name}"
    end
  end

  create_hello_method_for :john

ngpestelos

class MyClass
  attr_accessor :my_attribute
end

ngpestelos

# see Metaprogramming Ruby, p. 103

class MyClass
  def my_attribute=(value)
    @my_attribute = value
  end
  
  def my_attribute
    @my_attribute
  end

ngpestelos

# see Metaprogramming Ruby, p. 98

class FakeTime
  def self.now; 'Mon Apr 06 12:15:50'; end
end

require 'test/unit'

class TestLoan < Test::Unit::TestCase
  def test_conversion_to_string

ngpestelos

# see Metaprogramming Ruby, p. 98

class Loan
  def initialize(book)
    @book = book
    @time = Loan.time.now
  end
  
  def self.time
    @time_class || Time

ngpestelos

# see Metaprogramming Ruby, p. 96

class Loan
  def initialize(book)
    @book = book
    @time = Time.now
  end

  def to_s
    "#{@book.upcase} loaned on #{@time}"