Why does the OCaml std lib have so many non-tail-recursive functions?

Question

I have been rewriting many OCaml standard library functions to be tail-recursive lately. Given that this has entailed straight-forward CPS transformation, I am left puzzling ov

Answer 1

In my experience, tail recursive versions of non-trivial functions often trade space efficiency against time efficiency. In other words, the functions in the standard library might easily be faster for smallish inputs.