I'm not quite clear on the norms for posting content here, so pardon me if I'm missing the point; but it seems strange to post a page from a 10-year-old reference book, especially since (as far as I know) Lua coroutines haven't changed significantly since then, and it doesn't seem that there has been a new Lua release recently.

Were you pointing out something especially interesting about coroutines in general, or in Lua in particular?