OpenEuphoria

Considering that you apparently seem to be the original author of that phrase, and the delim functionality of flatten() itself in the first place, I think you would know that best.

(I would suggest modifying the docs to make that more explict in the future however: 'An optional delimiter to place after each flattened sub-sequence (except if the sub-sequence is the last element).')

I am curious as to the rationale, though, of distinguishing between the two cases. That is, why should flatten() only insert a delimiter up to the last subsequence (or last element that is a sequence), and continue to append atomic elements after that without a delimiter? Seems to open the door to other kinds of weird cases. (E.g. if flatten() is passed a sequence that is already flat, and also given a delimiter, should merely return the original string or should it insert a delimiter between each of the atomic elements?)