GETNEXT
GETNEXT(ctxnum);
GETNEXT(ctxnum);
GETNEXT(ctxnum);
GETNEXT(ctxnum);
GETNEXT(ctxnum);
#define MUSTEAT(c, e) (REQUIRE(MORE() && GETNEXT() == (c), e))
c = GETNEXT();
c = GETNEXT();
c = BACKSL | GETNEXT();
count = count*10 + (GETNEXT() - '0');