Multiple Returns With Ruby

I’ve been looking through a fair amount of code lately where the author has elected to use return with multiple values. For those who haven’t seen this witchery, it looks something like this:

def left_right(point, pivot)
return point - pivot, point + pivot
left_right(6, 4) # => [2, 10]

I am not a big fan of this and try to avoid it when I write code. To me it hides what is really happening, which is the fact that an array is being constructed that has heavy importance on the order of each value. It also forces you to use the return keyword, which I prefer not to have at all when I can avoid it. (+10 for Erlang not having return)

The same method can be rewritten as follows:

def left_right(point, pivot)
[point - pivot, point + pivot]
left_right(6, 4) # => [2, 10]

This, to me doesn’t feel to much better. It has to do with the fact we have created an ad-hoc datum object that will leave future readers slightly puzzled. After giving it some thought here is what I landed on for a solution I personally like.

class PivotPoints < Array
attr_reader :left, :right
def initialize(point, pivot)
@left = point - pivot
@right = point + pivot
self[0] = @left
self[1] = @right

“Why did I extend Array?”, you may ask. In this case only to be compatible with why the original multiple return was even a thing to begin with.

left, right = left_right(6, 4) # => [2, 10]
left # => 2
right # => 10

I also recommend avoiding this when you can as well. This ends my small rant on multiple returns… I urge everyone to avoid using them and instead realize there is a new data structure that is begging to be named.