So I see that it actually isn't possible to do what
I want, that the write operations to an event file
are limited to just positional information.  That's
unfortunate, I had really hoped it was possible to
simulate events via an external program.


.../src/libacme/acme.c:

int
winwriteevent(Win *w, Event *e)
{
char buf[100];

snprint(buf, sizeof buf, "%c%c%d %d \n", e->c1, e->c2, e->q0, e->q1);
return fswrite(wfid(w, "event"), buf, strlen(buf));
}