zainsadaqat/ruby

Self in Ruby

Everything is an object in ruby

puts self => main

puts self.class => Object

What behind the scene happening is: main = Object.new

Self inside an instance method

class Dog
  def bark
    self
  end
end

d = Dog.new
puts d == d.bark //true

Self inside of a class method

class Dog
  def self.bark
    self
  end
end

d = Dog.new
puts d == d.bark //true

Create multiple class level methods

class Dog
  def << self
    def bark
    end
    def chew
    end
    def fetch
    end
  end
end

all methods inside of def << self are class-level methods

First way to use Blocks

students = ["zain", "moaz", "leo", "ali"];

# One way to implement blocks
def each(array, &block) 
  i = 0;
  while i < array.length
    element = array[i]
    block.call(element) # one way
    i += 1
  end
end

each(students) do |student|
  puts "element == #{student}"
end

Second way to use Blocks

students = ["zain", "moaz", "leo", "ali"];

# Second way to implement block is using yield
def each(array)
  i = 0
  while i < array.length
    element = array[i]
    yield element # second way
    i += 1
  end
end

each(students) do |student|
  puts "element == #{student}"
end