I've been working on Ruby Koans and I've gotten to this part that I don't understand too well. Specifically, it's the about_dice_project, where they ask us to define a class to pass several pre-set tests. Originally, my class looked like
class DiceSet
attr_accessor :values
def initialize
@values = []
end
def roll(num)
num.times { |i| @values[i] = rand(1..6) }
return @values
end
end
But this failed the test below
dice = DiceSet.new
dice.roll(5)
first_time = dice.values
dice.roll(5)
second_time = dice.values
assert_not_equal first_time, second_time,
"Two rolls should not be equal"
And I realized after some testing that both first_time and second_time have the same object_id. So I looked on stackoverflow for some help and found this answer, which doesn't answer my question directly, but I did find a major difference in our code; namely, that instead of using the "num.times" way of rolling the dice, goes instead with
@values = Array.new(num) { rand(1..6) }
and this does pass the above test.
After finding this, I was trying to figure out why my original code didn't work, and so I thought that maybe Ruby was passing by reference, and that's why when the dice-rolling-method created a new array instead of modifying the existing array, that was a new object id created. But then I found this question, which says that Ruby is pass-by-value, and if that was the case, then I would have expected that my original way would work.
So now I'm confused again, and I'd like to ask - where did my line of thought go wrong? Is Ruby pass-by-value only in certain cases? Have I misunderstood what pass-by-value/reference even means? Is my issue not related to pass-by-value/reference at all?
