even_fibonacci.rb

def count_to limit, index = 1, nums = []
  if nums.empty?
    nums = [1,2]
  end
  if index == limit
    return (nums)
  else
    next_digit = nums[-2] + nums[-1]
    if next_digit <= limit
      nums << next_digit
    end
    index += 1
    count_to limit, index, nums
  end
end

def pluck_even nums, length = -1
  if length == -1
    length = nums.length
  end
  if length == 0
    return nums
  end
  length -= 1
  if nums[length] % 2 != 0
    nums.delete_at(length)
  end
  pluck_even( nums, length )
end

def sum arr, n = 0, sum = 0
 if n == arr.length
   return sum
 else
   sum += arr[n]
 end
 next_n = n + 1
 return sum(arr, next_n, sum)
end

p sum( pluck_even( count_to( 1_000 ) ) )