baeval
bval = baeval(bval, dtev);
bv->bv_value = baeval(ba, dtev);
bv->bv_value = baeval(ba, dtev);
bv->bv_value = baeval(ba, dtev);
ba = baeval(ba_read(bval), NULL);
bh = ba_append(bh, baeval(ba, dtev));
struct bt_arg *baeval(struct bt_arg *, struct dt_evt *);