User blog comment:DrCeasium/HAN: multidimensional arrays/@comment-5150073-20130713093431/@comment-7484840-20130714123238

I think the way the rule works is for the leftmost w(k)/ with k is less than the lowest separator in the array to the left to evaluate. An empty array has no separators, so k is always less than the lowest separator in this case, and so in your example, the final w/ will evaluate.