Going Backward

Go's standard library has a slices package with a function called Backward. It lets you iterate over the elements of a slice in reverse order: // Backward returns an iterator over index-value pairs in the slice, // traversing it backward with descending indices. func Backward[Slice ~[]E, E any](s Slice) iter.Seq2[int, E] If you're not deeply familiar with generics and iterators, the natural reaction to this signature (and to the others in the slices package) is: "couldn't this have been made simpler somehow?" To answer that, let's run a thought experiment. Let's picture ourselves as a distant ancestor, living in the pre-iterator era, who decided to implement Backward from scratch. Our imaginary ancestor doesn't work at Google, so don't project their decisions onto the Go development team. They had their own reasons — and no Jira. 1. A slice in reverse A pleasant, sunny summer day, birds singing. You're at the keyboard as usual, and suddenly you decide to write a function for walking a…