[jfries]

I really like that trick. It's very powerful. But I wonder what the difference is between this and protothreads?

[VygmraMGVl]

Protothreads is a library implementation of this trick. In fact, the protothreads creator even references the linked site in their explanation of protothreads (very last paragraph) [1].

[1] http://dunkels.com/adam/pt/expansion.html