static int luaB_dofile (lua_State *L) {  const char *fname = luaL_optstring(L, 1, NULL);  int n = lua_gettop(L);  if (luaL_loadfile(L, fname) != 0) lua_error(L);  lua_call(L, 0, LUA_MULTRET);  return lua_gettop(L) - n;}static int luaB_assert (lua_State *L) {  luaL_checkany(L, 1);  if (!lua_toboolean(L, 1))    return luaL_error(L, "%s", luaL_optstring(L, 2, "assertion failed!"));  return lua_gettop(L);}static int luaB_unpack (lua_State *L) {  int i, e, n;  luaL_checktype(L, 1, LUA_TTABLE);  i = luaL_optint(L, 2, 1);  e = luaL_opt(L, luaL_checkint, 3, luaL_getn(L, 1));  n = e - i + 1;  /* number of elements */  if (n <= 0) return 0;  /* empty range */  luaL_checkstack(L, n, "table too big to unpack");  for (; i<=e; i++)  /* push arg[i...e] */    lua_rawgeti(L, 1, i);  return n;}static int luaB_select (lua_State *L) {  int n = lua_gettop(L);  if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#') {    lua_pushinteger(L, n-1);    return 1;  }  else {    int i = luaL_checkint(L, 1);    if (i < 0) i = n + i;    else if (i > n) i = n;    luaL_argcheck(L, 1 <= i, 1, "index out of range");    return n - i;  }}static int luaB_pcall (lua_State *L) {  int status;  luaL_checkany(L, 1);  status = lua_pcall(L, lua_gettop(L) - 1, LUA_MULTRET, 0);  lua_pushboolean(L, (status == 0));  lua_insert(L, 1);  return lua_gettop(L);  /* return status + all results */}static int luaB_xpcall (lua_State *L) {  int status;  luaL_checkany(L, 2);  lua_settop(L, 2);  lua_insert(L, 1);  /* put error function under function to be called */  status = lua_pcall(L, 0, LUA_MULTRET, 1);  lua_pushboolean(L, (status == 0));  lua_replace(L, 1);  return lua_gettop(L);  /* return status + all results */}static int luaB_tostring (lua_State *L) {  luaL_checkany(L, 1);  if (luaL_callmeta(L, 1, "__tostring"))  /* is there a metafield? */    return 1;  /* use its value */  switch (lua_type(L, 1)) {    case LUA_TNUMBER:      lua_pushstring(L, lua_tostring(L, 1));      break;    case LUA_TSTRING:      lua_pushvalue(L, 1);      break;    case LUA_TBOOLEAN:      lua_pushstring(L, (lua_toboolean(L, 1) ? "true" : "false"));      break;    case LUA_TNIL:      lua_pushliteral(L, "nil");      break;    default:      lua_pushfstring(L, "%s: %p", luaL_typename(L, 1), lua_topointer(L, 1));      break;  }  return 1;}static int luaB_newproxy (lua_State *L) {  lua_settop(L, 1);  lua_newuserdata(L, 0);  /* create proxy */  if (lua_toboolean(L, 1) == 0)    return 1;  /* no metatable */  else if (lua_isboolean(L, 1)) {    lua_newtable(L);  /* create a new metatable `m' ... */    lua_pushvalue(L, -1);  /* ... and mark `m' as a valid metatable */    lua_pushboolean(L, 1);    lua_rawset(L, lua_upvalueindex(1));  /* weaktable[m] = true */  }  else {    int validproxy = 0;  /* to check if weaktable[metatable(u)] == true */    if (lua_getmetatable(L, 1)) {      lua_rawget(L, lua_upvalueindex(1));      validproxy = lua_toboolean(L, -1);      lua_pop(L, 1);  /* remove value */    }    luaL_argcheck(L, validproxy, 1, "boolean or proxy expected");    lua_getmetatable(L, 1);  /* metatable is valid; get it */  }  lua_setmetatable(L, 2);  return 1;}static const luaL_Reg base_funcs[] = {  {"assert", luaB_assert},  {"collectgarbage", luaB_collectgarbage},  {"dofile", luaB_dofile},  {"error", luaB_error},  {"gcinfo", luaB_gcinfo},  {"getfenv", luaB_getfenv},  {"getmetatable", luaB_getmetatable},  {"loadfile", luaB_loadfile},  {"load", luaB_load},  {"loadstring", luaB_loadstring},  {"next", luaB_next},  {"pcall", luaB_pcall},  {"print", luaB_print},  {"rawequal", luaB_rawequal},  {"rawget", luaB_rawget},  {"rawset", luaB_rawset},  {"select", luaB_select},  {"setfenv", luaB_setfenv},  {"setmetatable", luaB_setmetatable},  {"tonumber", luaB_tonumber},  {"tostring", luaB_tostring},  {"type", luaB_type},  {"unpack", luaB_unpack},  {"xpcall", luaB_xpcall},  {NULL, NULL}};/*** {======================================================** Coroutine library** =======================================================*/static int auxresume (lua_State *L, lua_State *co, int narg) {  int status;  if (!lua_checkstack(co, narg))    luaL_error(L, "too many arguments to resume");  if (lua_status(co) == 0 && lua_gettop(co) == 0) {    lua_pushliteral(L, "cannot resume dead coroutine");    return -1;  /* error flag */  }  lua_xmove(L, co, narg);  status = lua_resume(co, narg);  if (status == 0 || status == LUA_YIELD) {    int nres = lua_gettop(co);    if (!lua_checkstack(L, nres))      luaL_error(L, "too many results to resume");    lua_xmove(co, L, nres);  /* move yielded values */    return nres;  }  else {    lua_xmove(co, L, 1);  /* move error message */    return -1;  /* error flag */  }}static int luaB_coresume (lua_State *L) {  lua_State *co = lua_tothread(L, 1);  int r;  luaL_argcheck(L, co, 1, "coroutine expected");  r = auxresume(L, co, lua_gettop(L) - 1);  if (r < 0) {    lua_pushboolean(L, 0);    lua_insert(L, -2);    return 2;  /* return false + error message */  }  else {    lua_pushboolean(L, 1);    lua_insert(L, -(r + 1));    return r + 1;  /* return true + `resume' returns */  }}static int luaB_auxwrap (lua_State *L) {  lua_State *co = lua_tothread(L, lua_upvalueindex(1));  int r = auxresume(L, co, lua_gettop(L));  if (r < 0) {    if (lua_isstring(L, -1)) {  /* error object is a string? */      luaL_where(L, 1);  /* add extra info */      lua_insert(L, -2);      lua_concat(L, 2);    }    lua_error(L);  /* propagate error */  }  return r;}static int luaB_cocreate (lua_State *L) {  lua_State *NL = lua_newthread(L);  luaL_argcheck(L, lua_isfunction(L, 1) && !lua_iscfunction(L, 1), 1,    "Lua function expected");  lua_pushvalue(L, 1);  /* move function to top */  lua_xmove(L, NL, 1);  /* move function from L to NL */  return 1;}static int luaB_cowrap (lua_State *L) {  luaB_cocreate(L);  lua_pushcclosure(L, luaB_auxwrap, 1);  return 1;}static int luaB_yield (lua_State *L) {  return lua_yield(L, lua_gettop(L));}static int luaB_costatus (lua_State *L) {  lua_State *co = lua_tothread(L, 1);  luaL_argcheck(L, co, 1, "coroutine expected");  if (L == co) lua_pushliteral(L, "running");  else {    switch (lua_status(co)) {      case LUA_YIELD:        lua_pushliteral(L, "suspended");        break;      case 0: {        lua_Debug ar;        if (lua_getstack(co, 0, &ar) > 0)  /* does it have frames? */          lua_pushliteral(L, "normal");  /* it is running */        else if (lua_gettop(co) == 0)            lua_pushliteral(L, "dead");        else          lua_pushliteral(L, "suspended");  /* initial state */        break;      }      default:  /* some error occured */        lua_pushliteral(L, "dead");        break;    }  }  return 1;}static int luaB_corunning (lua_State *L) {  if (lua_pushthread(L))    return 0;  /* main thread is not a coroutine */  else    return 1;}static const luaL_Reg co_funcs[] = {  {"create", luaB_cocreate},  {"resume", luaB_coresume},  {"running", luaB_corunning},  {"status", luaB_costatus},  {"wrap", luaB_cowrap},  {"yield", luaB_yield},  {NULL, NULL}};/* }====================================================== */static void auxopen (lua_State *L, const char *name,                     lua_CFunction f, lua_CFunction u) {  lua_pushcfunction(L, u);  lua_pushcclosure(L, f, 1);  lua_setfield(L, -2, name);}static void base_open (lua_State *L) {  /* set global _G */  lua_pushvalue(L, LUA_GLOBALSINDEX);  lua_setglobal(L, "_G");  /* open lib into global table */  luaL_register(L, "_G", base_funcs);  lua_pushliteral(L, LUA_VERSION);  lua_setglobal(L, "_VERSION");  /* set global _VERSION */  /* `ipairs' and `pairs' need auxliliary functions as upvalues */  auxopen(L, "ipairs", luaB_ipairs, ipairsaux);  auxopen(L, "pairs", luaB_pairs, luaB_next);  /* `newproxy' needs a weaktable as upvalue */  lua_createtable(L, 0, 1);  /* new table `w' */  lua_pushvalue(L, -1);  /* `w' will be its own metatable */  lua_setmetatable(L, -2);  lua_pushliteral(L, "kv");  lua_setfield(L, -2, "__mode");  /* metatable(w).__mode = "kv" */  lua_pushcclosure(L, luaB_newproxy, 1);  lua_setglobal(L, "newproxy");  /* set global `newproxy' */}LUALIB_API int luaopen_base (lua_State *L) {  base_open(L);  luaL_register(L, LUA_COLIBNAME, co_funcs);  return 2;}