As usual, it's at <http://ccil.org/~cowan/temp/srfi-121.html>

The rationale has been heavily rewritten using text from some of Shiro's
postings.  Please review it.

Null generators are now called empty generators (cf. empty list, empty string).

Gmerge, gunion, and gintersection are now accompanied by gdifference and gxor,
which accept only two arguments.

Gfilter-map, gstate-filter, and generator-collect have been flushed either
for obscurity or for triviality.

Clarified that gnth-value always returns the first (0th) element of its source.

Many, many editorial changes.  Probably more to come.

--
John Cowan          http://www.ccil.org/~cowan        xxxxxx@ccil.org
While staying with the Asonu, I met a man from the Candensian plane,
which is very much like ours, only more of it consists of Toronto.
        --Ursula K. Le Guin, Changing Planes