static int
ngx_http_lua_shdict_delete(lua_State *L)
{
    int             n;

    n = lua_gettop(L);

    if (n != 2) {
        return luaL_error(L, "expecting 2 arguments, "
                "but only seen %d", n);
    }

    lua_pushnil(L);

    return ngx_http_lua_shdict_set_helper(L, 0);
}
static int
ngx_http_lua_shdict_set(lua_State *L)
{
    return ngx_http_lua_shdict_set_helper(L, 0);
}
static int
ngx_http_lua_shdict_replace(lua_State *L)
{
    return ngx_http_lua_shdict_set_helper(L, NGX_HTTP_LUA_SHDICT_REPLACE);
}
static int
ngx_http_lua_shdict_add(lua_State *L)
{
    return ngx_http_lua_shdict_set_helper(L, NGX_HTTP_LUA_SHDICT_ADD);
}
static int
ngx_http_lua_shdict_safe_set(lua_State *L)
{
    return ngx_http_lua_shdict_set_helper(L, NGX_HTTP_LUA_SHDICT_SAFE_STORE);
}