MF_TRY1NULL
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY1NULL;
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY1NULL;
if (val.dptr == NULL && bitset(MF_TRY1NULL, map->map_mflags))
map->map_mflags &= ~MF_TRY1NULL;
map->map_mflags &= ~MF_TRY1NULL;
if (st != 0 && bitset(MF_TRY1NULL, map->map_mflags))
map->map_mflags &= ~MF_TRY1NULL;
if (yperr == YPERR_KEY && bitset(MF_TRY1NULL, map->map_mflags))
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY1NULL;
if (map.map_mflags != (MF_TRY0NULL|MF_TRY1NULL) ||
map->map_mflags |= MF_TRY0NULL|MF_TRY1NULL;
map->map_mflags &= ~MF_TRY1NULL;