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Am 20.08.2016 um 10:04 schröbte Tim Hill:

On Aug 19, 2016, at 11:50 AM, Ross Berteig <> wrote:

Since you already need to iterate, then iterating until nil saves you the additional O(log n) cost from `#t`.

Yet again, #t and iterating t to the first nil rears it’s ugly head.

If `t` contains a sequence, then the first `nil` you'll encounter is also the only `nil`, and marks the end of the sequence. So it actually conforms to the definition of `#` (ignoring metamethods for the moment). Additionally, it also has defined behavior (however useful it might be) if `t` does not contain a proper sequence. It also allows you to handle sequences that change their sizes during iteration, and it is cheap to do in C code. So this approach seems like a reasonable option given the current state of things.