Software, Development, Ruby and Internet > Marc Anguera Insa

04/10/2013

Calling super in Ruby

Ruby, like most programming languages, has a set of reserved identifiers, keywords: if, else, return, do, while, self, yield, true, false, etc.

Next we’ll talk about super. We should use it when we want to take some behavior of an already defined method. For example, when implementing inheritance or overriding methods from a plugin.

In Ruby context, this means “call the method with the same name along the classes and modules available to the current object”.

When using super, be careful with syntax. Called with omitted arguments (without parentheses), it acts differently than passing an empty argument list:

  • super: calls with the same arguments as those used to call the current method.

  • super(): calls with empty arguments list.

Scenario

Example how super performs in different cases:

class A
  def initialize(*args)
    puts args.inspect
  end
end

class B < A
  def initialize(args)
    super()
    super # same as super(args)
  end
end

B.new('foo')
# => []
# => ["foo"]