Simple example for myself of a recursive function to compute the sum of a list.

recursive_sum.rb

#!/usr/bin/ruby
def sums(list)
        if list.length > 1
                return list.pop + sums(list)
        else
                return list.pop
        end
end

#Make a list.
my_list = [3, 2, 4, 1]
the_sum = sums(my_list)
puts "The sum of the list is: #{the_sum}"