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Ruby Ruby Modules Ruby Core Modules Comparable

Patrick Shushereba
Patrick Shushereba
10,911 Points
Posted by Patrick Shushereba
Patrick Shushereba
10,911 Points

Using the Spaceship operator

I had a quick question regarding one of the Ruby lessons.

Here is the code from the lesson:

class Player
  include Comparable

  attr_accessor :name, :score

  def <=>(other_player)
    score <=> other_player.score
  end

  def initialize(name, score)
    @name = name
    @score = score
  end
end

player1 = Player.new("Jason", 100)
player2 = Player.new("Kenneth", 80)

puts "player1 > player2: %s" % (player1 > player2)
puts "player1 < player2: %s" % (player1 < player2)

My question is when Jason goes to define the spaceship operator, he passes in other_player as an argument. How does the comparison between the two players take place when other_players isn't referenced anywhere else? How does this manage to evaluate to true?

2 Answers

Brian O'Grady
Brian O'Grady
10,094 Points
Brian O'Grady
Brian O'Grady
10,094 Points

In this section the argument is only a descriptor and not a variable. It does not need to be defined it only relates that the score of the player in question is bigger, smaller or equal to the other_player.score.

Ruby works with arguments like that.

Ulfar Ellenarson
Ulfar Ellenarson
5,277 Points
Ulfar Ellenarson
Ulfar Ellenarson
5,277 Points

To expand on Brian's answer the other_player as a descriptor; example would be that you could use any name you like. Try changing the parameter other_player to my_player or compare_me and it will still work.