Quirky Privates

Just one of those little Ruby language quirks. Normally, you have to use the implicit receiver when sending a private message. This can be demonstrated as follows:

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class Quirky
  def send_private_explicitly
    self.say_hello    # => NoMethodError: private method 'say_hello'
  end

  def send_private_implicitly
    say_hello         # => "Hi there friend!"
  end

  private

  def say_hello
    puts "Hi there friend!"
  end
end

However, this is not true when sending a message that ends in =. In this case you must use the explicit receiver self.

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class Quirky
  def send_private_setter_explicitly
    self.store_value = 'friend'     # => @private_value='friend'
    store_value                     # => "Let's get our private value"
  end

  def send_private_setter_implicitly
    store_value = 'friend'          # => @private_value is not set
    store_value                     # => 'friend'
  end

  private

  def store_value=(value)
    @private_value = value
  end

  def store_value
    puts "Let's get our private value"
  end
end

In fact, without the explicit reciever self when sending a private message ending in =, you will instead create a local variable with that name. This is then the reference point for the rest of the method body.