luaL_optinteger
#define luaL_optint(L,n,d) ((int)luaL_optinteger(L, (n), (d)))
#define luaL_optlong(L,n,d) ((long)luaL_optinteger(L, (n), (d)))
LUALIB_API lua_Integer (luaL_optinteger) (lua_State *L, int nArg,
size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
size_t max_s = luaL_optinteger(L, 4, srcl+1);
size_t end = posrelat(luaL_optinteger(L, 3, -1), l);