Singletons and companion objects

Scala's syntax for singleton objects and the methods thereupon is one my favorite first-blush features of the language:

object MySingletonObject {
def singletonMethod() = println("What a fancy method, and so singular!")
}

So now if you want that supremely valuable console message, just call MySingletonObject.singletonMethod().

Say, though, that you want the equivalent to this bit of Ruby code:

class MyClass
def say_hi
  print "hi"
end

def self.say_yo_from_the_class
  print "yo"
end
end

>> m = MyClass.new
=> #
>> m.say_hi
hi=> nil
>> MyClass.say_yo_from_the_class
yo=> nil

You've got MyClass defined in your Scala code, but how to get that badass say_yo_from_the_class class method? Like this, kid:

object MyClass {
def sayYoFromTheClass() = println("yo")
}

The above singleton is now the companion object of MyClass. Companion objects have to be defined the same source file as the class they accompany. Other than that, pretty intuitive.