[Ruby] Blocks

Using Blocks:

words = ['Had', 'eggs', 'for', 'breakfast']
for index in 0...(words.length-1)
    puts words[index]
end


words = ['Had', 'eggs', 'for', 'breakfast']
words.each{ |word| puts word}

 

 

 

 

Yield:

Excude a block.

 

 

Yield with arguments:

def call_this_block
    yeild "tweet"
end


call_this_block {|myarg| puts myarg}  -------> tweet
call_this_block {|myarg| puts myarg.upcase} ---------TWEET

 

Yield return value:

def puts_this_block
    puts yield
end


puts_this_block {"tweet"}  ---->tweet

 

 

 

Using Blocks:

 

 

 

Enumerable module:

class Timeline
    def each
        ...
    end
    include Enumerable
end


timeline.sort_by { |tweet| tweet.created_at}
timeline.map {|tweet| tweet.status}
timeline.find-all {|tweet| tweet.status == ~/\@codeschool/}

You instantly get all these methods, and more!

 

 

 

class Game
  attr_accessor :name, :year, :system
  attr_reader :created_at

  def initialize(name, options={})
    self.name = name
    self.year = options[:year]
    self.system = options[:system]
    @created_at = Time.now
  end

  def play
    emulate do |emulator|
      emulator.play(self)
    end
  end

  def screenshot
    emulate do |emulator|
      emulator.start(self)
      emulator.screenshot
    end
  end
  
  private 
  
  def emulate
        emulator = Emulator.new(system)
        yield emulator
    rescue Exception => e
      puts "Emulator failed: #{e}"     
  end
  
end