Various notes:
Coroutines and continuations are related concepts. Roberto
Ierusalimschy's
papers
include his 1994 "Revisiting Coroutines", with a very nice overview of
coroutine stuff. It seems to touch on every flavor of coroutine other
than Simon Peyton Jones's "cheap continuations". (He's also the
creator of Lua.)
Adam Dunkels,
creator of
Protothreads,
gives a bunch of useful
links on threads, continuations, coroutines.
