http://www.w3.org/TR/xquery-operators/#func-string-join

The first two examples for string-join() are unclear with regard to whitespace. Currently, they read:

fn:string-join(('Now', 'is', 'the', 'time', '...'), ' ') returns " Now is the time ... ".

There is a space character before "Now" and one after "...". Does this mean that "as a separator" means the separator is put in front of, between and after the $arg1 sequence elements?

fn:string-join(('Blow, ', 'blow, ', 'thou ', 'winter ', 'wind!'), '') returns " Blow, blow, thou winter wind! ".

Again, there is whitespace before "Blow" and after "wind!" - but here, the separator is the empty string. Why is there a single whitespace generated before the first and after the last sequence element?

I suspect the single whitespace at the beginning and end of the samples is an error in both cases, and that the separator is only added between two items of the $arg1 sequence. In this case, the superfluous whitespace should be removed in the examples, since as it is now, it is not totally clear whether it's a bug or a trait of the function.