[plt-scheme] HTDP Section 18 Pragmatics of local, Part 2

> Thanks so much, but I am still not clear here. I understand star?very well,
> however how could (star? .........) be true when
>
> (last-occurrence s (rest alostars)) (rest alotars) is a list not a
> structure. That's what I have not yet understood.
>
>

But you are wrong......

The contract for last-occurence is:

    ;; last-occurrence : symbol list-of-star  ->  star or false

It never returns a list! :-)

-- 

Cheers,

Marco