Going Backward

A thought experiment walking through the iterative design decisions behind Go's slices.Backward function. Starting from a naive slice-copying approach, the post evolves the implementation step by step: from a closure-based pull iterator, to a callback-based push iterator with a yield function, to adding index-value pairs (Seq2), and finally to supporting user-defined slice types using the ~T generic constraint. Each step explains the tradeoff that motivates the next, ultimately arriving at the same signature found in Go's standard library.