src/lib/lbaselib.c

   1 /*
   2 ** $Id: lbaselib.c,v 1.130a 2003/04/03 13:35:34 roberto Exp $
   3 ** Basic library
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8
   9 #include <ctype.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #define lbaselib_c
  15
  16 #include "lua.h"
  17
  18 #include "lauxlib.h"
  19 #include "lualib.h"
  20
  21
  22
  23
  24 /*
  25 ** If your system does not support `stdout', you can just remove this function.
  26 ** If you need, you can define your own `print' function, following this
  27 ** model but changing `fputs' to put the strings at a proper place
  28 ** (a console window or a log file, for instance).
  29 */
  30 static int luaB_print (lua_State *L) {
  31   int n = lua_gettop(L);  /* number of arguments */
  32   int i;
  33   lua_getglobal(L, "tostring");
  34   for (i=1; i<=n; i++) {
  35     const char *s;
  36     lua_pushvalue(L, -1);  /* function to be called */
  37     lua_pushvalue(L, i);   /* value to print */
  38     lua_call(L, 1, 1);
  39     s = lua_tostring(L, -1);  /* get result */
  40     if (s == NULL)
  41       return luaL_error(L, "`tostring' must return a string to `print'");
  42     if (i>1) fputs("\t", stdout);
  43     fputs(s, stdout);
  44     lua_pop(L, 1);  /* pop result */
  45   }
  46   fputs("\n", stdout);
  47   return 0;
  48 }
  49
  50
  51 static int luaB_tonumber (lua_State *L) {
  52   int base = luaL_optint(L, 2, 10);
  53   if (base == 10) {  /* standard conversion */
  54     luaL_checkany(L, 1);
  55     if (lua_isnumber(L, 1)) {
  56       lua_pushnumber(L, lua_tonumber(L, 1));
  57       return 1;
  58     }
  59   }
  60   else {
  61     const char *s1 = luaL_checkstring(L, 1);
  62     char *s2;
  63     unsigned long n;
  64     luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
  65     n = strtoul(s1, &s2, base);
  66     if (s1 != s2) {  /* at least one valid digit? */
  67       while (isspace((unsigned char)(*s2))) s2++;  /* skip trailing spaces */
  68       if (*s2 == '\0') {  /* no invalid trailing characters? */
  69         lua_pushnumber(L, (lua_Number)n);
  70         return 1;
  71       }
  72     }
  73   }
  74   lua_pushnil(L);  /* else not a number */
  75   return 1;
  76 }
  77
  78
  79 static int luaB_error (lua_State *L) {
  80   int level = luaL_optint(L, 2, 1);
  81   luaL_checkany(L, 1);
  82   if (!lua_isstring(L, 1) || level == 0)
  83     lua_pushvalue(L, 1);  /* propagate error message without changes */
  84   else {  /* add extra information */
  85     luaL_where(L, level);
  86     lua_pushvalue(L, 1);
  87     lua_concat(L, 2);
  88   }
  89   return lua_error(L);
  90 }
  91
  92
  93 static int luaB_getmetatable (lua_State *L) {
  94   luaL_checkany(L, 1);
  95   if (!lua_getmetatable(L, 1)) {
  96     lua_pushnil(L);
  97     return 1;  /* no metatable */
  98   }
  99   luaL_getmetafield(L, 1, "__metatable");
 100   return 1;  /* returns either __metatable field (if present) or metatable */
 101 }
 102
 103
 104 static int luaB_setmetatable (lua_State *L) {
 105   int t = lua_type(L, 2);
 106   luaL_checktype(L, 1, LUA_TTABLE);
 107   luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
 108                     "nil or table expected");
 109   if (luaL_getmetafield(L, 1, "__metatable"))
 110     luaL_error(L, "cannot change a protected metatable");
 111   lua_settop(L, 2);
 112   lua_setmetatable(L, 1);
 113   return 1;
 114 }
 115
 116
 117 static void getfunc (lua_State *L) {
 118   if (lua_isfunction(L, 1)) lua_pushvalue(L, 1);
 119   else {
 120     lua_Debug ar;
 121     int level = luaL_optint(L, 1, 1);
 122     luaL_argcheck(L, level >= 0, 1, "level must be non-negative");
 123     if (lua_getstack(L, level, &ar) == 0)
 124       luaL_argerror(L, 1, "invalid level");
 125     lua_getinfo(L, "f", &ar);
 126     if (lua_isnil(L, -1))
 127       luaL_error(L, "no function environment for tail call at level %d",
 128                     level);
 129   }
 130 }
 131
 132
 133 static int aux_getfenv (lua_State *L) {
 134   lua_getfenv(L, -1);
 135   lua_pushliteral(L, "__fenv");
 136   lua_rawget(L, -2);
 137   return !lua_isnil(L, -1);
 138 }
 139
 140
 141 static int luaB_getfenv (lua_State *L) {
 142   getfunc(L);
 143   if (!aux_getfenv(L))  /* __fenv not defined? */
 144     lua_pop(L, 1);  /* remove it, to return real environment */
 145   return 1;
 146 }
 147
 148
 149 static int luaB_setfenv (lua_State *L) {
 150   luaL_checktype(L, 2, LUA_TTABLE);
 151   getfunc(L);
 152   if (aux_getfenv(L))  /* __fenv defined? */
 153     luaL_error(L, "`setfenv' cannot change a protected environment");
 154   else
 155     lua_pop(L, 2);  /* remove __fenv and real environment table */
 156   lua_pushvalue(L, 2);
 157   if (lua_isnumber(L, 1) && lua_tonumber(L, 1) == 0)
 158     lua_replace(L, LUA_GLOBALSINDEX);
 159   else if (lua_setfenv(L, -2) == 0)
 160     luaL_error(L, "`setfenv' cannot change environment of given function");
 161   return 0;
 162 }
 163
 164
 165 static int luaB_rawequal (lua_State *L) {
 166   luaL_checkany(L, 1);
 167   luaL_checkany(L, 2);
 168   lua_pushboolean(L, lua_rawequal(L, 1, 2));
 169   return 1;
 170 }
 171
 172
 173 static int luaB_rawget (lua_State *L) {
 174   luaL_checktype(L, 1, LUA_TTABLE);
 175   luaL_checkany(L, 2);
 176   lua_rawget(L, 1);
 177   return 1;
 178 }
 179
 180 static int luaB_rawset (lua_State *L) {
 181   luaL_checktype(L, 1, LUA_TTABLE);
 182   luaL_checkany(L, 2);
 183   luaL_checkany(L, 3);
 184   lua_rawset(L, 1);
 185   return 1;
 186 }
 187
 188
 189 static int luaB_gcinfo (lua_State *L) {
 190   lua_pushnumber(L, (lua_Number)lua_getgccount(L));
 191   lua_pushnumber(L, (lua_Number)lua_getgcthreshold(L));
 192   return 2;
 193 }
 194
 195
 196 static int luaB_collectgarbage (lua_State *L) {
 197   lua_setgcthreshold(L, luaL_optint(L, 1, 0));
 198   return 0;
 199 }
 200
 201
 202 static int luaB_type (lua_State *L) {
 203   luaL_checkany(L, 1);
 204   lua_pushstring(L, lua_typename(L, lua_type(L, 1)));
 205   return 1;
 206 }
 207
 208
 209 static int luaB_next (lua_State *L) {
 210   luaL_checktype(L, 1, LUA_TTABLE);
 211   lua_settop(L, 2);  /* create a 2nd argument if there isn't one */
 212   if (lua_next(L, 1))
 213     return 2;
 214   else {
 215     lua_pushnil(L);
 216     return 1;
 217   }
 218 }
 219
 220
 221 static int luaB_pairs (lua_State *L) {
 222   luaL_checktype(L, 1, LUA_TTABLE);
 223   lua_pushliteral(L, "next");
 224   lua_rawget(L, LUA_GLOBALSINDEX);  /* return generator, */
 225   lua_pushvalue(L, 1);  /* state, */
 226   lua_pushnil(L);  /* and initial value */
 227   return 3;
 228 }
 229
 230
 231 static int luaB_ipairs (lua_State *L) {
 232   lua_Number i = lua_tonumber(L, 2);
 233   luaL_checktype(L, 1, LUA_TTABLE);
 234   if (i == 0 && lua_isnone(L, 2)) {  /* `for' start? */
 235     lua_pushliteral(L, "ipairs");
 236     lua_rawget(L, LUA_GLOBALSINDEX);  /* return generator, */
 237     lua_pushvalue(L, 1);  /* state, */
 238     lua_pushnumber(L, 0);  /* and initial value */
 239     return 3;
 240   }
 241   else {  /* `for' step */
 242     i++;  /* next value */
 243     lua_pushnumber(L, i);
 244     lua_rawgeti(L, 1, (int)i);
 245     return (lua_isnil(L, -1)) ? 0 : 2;
 246   }
 247 }
 248
 249
 250 static int load_aux (lua_State *L, int status) {
 251   if (status == 0)  /* OK? */
 252     return 1;
 253   else {
 254     lua_pushnil(L);
 255     lua_insert(L, -2);  /* put before error message */
 256     return 2;  /* return nil plus error message */
 257   }
 258 }
 259
 260
 261 static int luaB_loadstring (lua_State *L) {
 262   size_t l;
 263   const char *s = luaL_checklstring(L, 1, &l);
 264   const char *chunkname = luaL_optstring(L, 2, s);
 265   return load_aux(L, luaL_loadbuffer(L, s, l, chunkname));
 266 }
 267
 268
 269 static int luaB_loadfile (lua_State *L) {
 270   const char *fname = luaL_optstring(L, 1, NULL);
 271   return load_aux(L, luaL_loadfile(L, fname));
 272 }
 273
 274
 275 static int luaB_dofile (lua_State *L) {
 276   const char *fname = luaL_optstring(L, 1, NULL);
 277   int status = luaL_loadfile(L, fname);
 278   if (status != 0) lua_error(L);
 279   lua_call(L, 0, LUA_MULTRET);
 280   return lua_gettop(L) - 1;
 281 }
 282
 283
 284 static int luaB_assert (lua_State *L) {
 285   luaL_checkany(L, 1);
 286   if (!lua_toboolean(L, 1))
 287     return luaL_error(L, "%s", luaL_optstring(L, 2, "assertion failed!"));
 288   lua_settop(L, 1);
 289   return 1;
 290 }
 291
 292
 293 static int luaB_unpack (lua_State *L) {
 294   int n, i;
 295   luaL_checktype(L, 1, LUA_TTABLE);
 296   n = luaL_getn(L, 1);
 297   luaL_checkstack(L, n, "table too big to unpack");
 298   for (i=1; i<=n; i++)  /* push arg[1...n] */
 299     lua_rawgeti(L, 1, i);
 300   return n;
 301 }
 302
 303
 304 static int luaB_pcall (lua_State *L) {
 305   int status;
 306   luaL_checkany(L, 1);
 307   status = lua_pcall(L, lua_gettop(L) - 1, LUA_MULTRET, 0);
 308   lua_pushboolean(L, (status == 0));
 309   lua_insert(L, 1);
 310   return lua_gettop(L);  /* return status + all results */
 311 }
 312
 313
 314 static int luaB_xpcall (lua_State *L) {
 315   int status;
 316   luaL_checkany(L, 2);
 317   lua_settop(L, 2);
 318   lua_insert(L, 1);  /* put error function under function to be called */
 319   status = lua_pcall(L, 0, LUA_MULTRET, 1);
 320   lua_pushboolean(L, (status == 0));
 321   lua_replace(L, 1);
 322   return lua_gettop(L);  /* return status + all results */
 323 }
 324
 325
 326 static int luaB_tostring (lua_State *L) {
 327   char buff[128];
 328   luaL_checkany(L, 1);
 329   if (luaL_callmeta(L, 1, "__tostring"))  /* is there a metafield? */
 330     return 1;  /* use its value */
 331   switch (lua_type(L, 1)) {
 332     case LUA_TNUMBER:
 333       lua_pushstring(L, lua_tostring(L, 1));
 334       return 1;
 335     case LUA_TSTRING:
 336       lua_pushvalue(L, 1);
 337       return 1;
 338     case LUA_TBOOLEAN:
 339       lua_pushstring(L, (lua_toboolean(L, 1) ? "true" : "false"));
 340       return 1;
 341     case LUA_TTABLE:
 342       sprintf(buff, "table: %p", lua_topointer(L, 1));
 343       break;
 344     case LUA_TFUNCTION:
 345       sprintf(buff, "function: %p", lua_topointer(L, 1));
 346       break;
 347     case LUA_TUSERDATA:
 348     case LUA_TLIGHTUSERDATA:
 349       sprintf(buff, "userdata: %p", lua_touserdata(L, 1));
 350       break;
 351     case LUA_TTHREAD:
 352       sprintf(buff, "thread: %p", (void *)lua_tothread(L, 1));
 353       break;
 354     case LUA_TNIL:
 355       lua_pushliteral(L, "nil");
 356       return 1;
 357   }
 358   lua_pushstring(L, buff);
 359   return 1;
 360 }
 361
 362
 363 static int luaB_newproxy (lua_State *L) {
 364   lua_settop(L, 1);
 365   lua_newuserdata(L, 0);  /* create proxy */
 366   if (lua_toboolean(L, 1) == 0)
 367     return 1;  /* no metatable */
 368   else if (lua_isboolean(L, 1)) {
 369     lua_newtable(L);  /* create a new metatable `m' ... */
 370     lua_pushvalue(L, -1);  /* ... and mark `m' as a valid metatable */
 371     lua_pushboolean(L, 1);
 372     lua_rawset(L, lua_upvalueindex(1));  /* weaktable[m] = true */
 373   }
 374   else {
 375     int validproxy = 0;  /* to check if weaktable[metatable(u)] == true */
 376     if (lua_getmetatable(L, 1)) {
 377       lua_rawget(L, lua_upvalueindex(1));
 378       validproxy = lua_toboolean(L, -1);
 379       lua_pop(L, 1);  /* remove value */
 380     }
 381     luaL_argcheck(L, validproxy, 1, "boolean or proxy expected");
 382     lua_getmetatable(L, 1);  /* metatable is valid; get it */
 383   }
 384   lua_setmetatable(L, 2);
 385   return 1;
 386 }
 387
 388
 389 /*
 390 ** {======================================================
 391 ** `require' function
 392 ** =======================================================
 393 */
 394
 395
 396 /* name of global that holds table with loaded packages */
 397 #define REQTAB          "_LOADED"
 398
 399 /* name of global that holds the search path for packages */
 400 #define LUA_PATH        "LUA_PATH"
 401
 402 #ifndef LUA_PATH_SEP
 403 #define LUA_PATH_SEP    ';'
 404 #endif
 405
 406 #ifndef LUA_PATH_MARK
 407 #define LUA_PATH_MARK   '?'
 408 #endif
 409
 410 #ifndef LUA_PATH_DEFAULT
 411 #define LUA_PATH_DEFAULT        "?;?.lua"
 412 #endif
 413
 414
 415 static const char *getpath (lua_State *L) {
 416   const char *path;
 417   lua_getglobal(L, LUA_PATH);  /* try global variable */
 418   path = lua_tostring(L, -1);
 419   lua_pop(L, 1);
 420   if (path) return path;
 421   path = getenv(LUA_PATH);  /* else try environment variable */
 422   if (path) return path;
 423   return LUA_PATH_DEFAULT;  /* else use default */
 424 }
 425
 426
 427 static const char *pushnextpath (lua_State *L, const char *path) {
 428   const char *l;
 429   if (*path == '\0') return NULL;  /* no more paths */
 430   if (*path == LUA_PATH_SEP) path++;  /* skip separator */
 431   l = strchr(path, LUA_PATH_SEP);  /* find next separator */
 432   if (l == NULL) l = path+strlen(path);
 433   lua_pushlstring(L, path, l - path);  /* directory name */
 434   return l;
 435 }
 436
 437
 438 static void pushcomposename (lua_State *L) {
 439   const char *path = lua_tostring(L, -1);
 440   const char *wild;
 441   int n = 1;
 442   while ((wild = strchr(path, LUA_PATH_MARK)) != NULL) {
 443     /* is there stack space for prefix, name, and eventual last sufix? */
 444     luaL_checkstack(L, 3, "too many marks in a path component");
 445     lua_pushlstring(L, path, wild - path);  /* push prefix */
 446     lua_pushvalue(L, 1);  /* push package name (in place of MARK) */
 447     path = wild + 1;  /* continue after MARK */
 448     n += 2;
 449   }
 450   lua_pushstring(L, path);  /* push last sufix (`n' already includes this) */
 451   lua_concat(L, n);
 452 }
 453
 454
 455 static int luaB_require (lua_State *L) {
 456   const char *path;
 457   int status = LUA_ERRFILE;  /* not found (yet) */
 458   luaL_checkstring(L, 1);
 459   lua_settop(L, 1);
 460   lua_getglobal(L, REQTAB);
 461   if (!lua_istable(L, 2)) return luaL_error(L, "`" REQTAB "' is not a table");
 462   path = getpath(L);
 463   lua_pushvalue(L, 1);  /* check package's name in book-keeping table */
 464   lua_rawget(L, 2);
 465   if (lua_toboolean(L, -1))  /* is it there? */
 466     return 1;  /* package is already loaded; return its result */
 467   else {  /* must load it */
 468     while (status == LUA_ERRFILE) {
 469       lua_settop(L, 3);  /* reset stack position */
 470       if ((path = pushnextpath(L, path)) == NULL) break;
 471       pushcomposename(L);
 472       status = luaL_loadfile(L, lua_tostring(L, -1));  /* try to load it */
 473     }
 474   }
 475   switch (status) {
 476     case 0: {
 477       lua_getglobal(L, "_REQUIREDNAME");  /* save previous name */
 478       lua_insert(L, -2);  /* put it below function */
 479       lua_pushvalue(L, 1);
 480       lua_setglobal(L, "_REQUIREDNAME");  /* set new name */
 481       lua_call(L, 0, 1);  /* run loaded module */
 482       lua_insert(L, -2);  /* put result below previous name */
 483       lua_setglobal(L, "_REQUIREDNAME");  /* reset to previous name */
 484       if (lua_isnil(L, -1)) {  /* no/nil return? */
 485         lua_pushboolean(L, 1);
 486         lua_replace(L, -2);  /* replace to true */
 487       }
 488       lua_pushvalue(L, 1);
 489       lua_pushvalue(L, -2);
 490       lua_rawset(L, 2);  /* mark it as loaded */
 491       return 1;  /* return value */
 492     }
 493     case LUA_ERRFILE: {  /* file not found */
 494       return luaL_error(L, "could not load package `%s' from path `%s'",
 495                             lua_tostring(L, 1), getpath(L));
 496     }
 497     default: {
 498       return luaL_error(L, "error loading package `%s' (%s)",
 499                            lua_tostring(L, 1), lua_tostring(L, -1));
 500     }
 501   }
 502 }
 503
 504 /* }====================================================== */
 505
 506
 507 static const luaL_reg base_funcs[] = {
 508   {"error", luaB_error},
 509   {"getmetatable", luaB_getmetatable},
 510   {"setmetatable", luaB_setmetatable},
 511   {"getfenv", luaB_getfenv},
 512   {"setfenv", luaB_setfenv},
 513   {"next", luaB_next},
 514   {"ipairs", luaB_ipairs},
 515   {"pairs", luaB_pairs},
 516   {"print", luaB_print},
 517   {"tonumber", luaB_tonumber},
 518   {"tostring", luaB_tostring},
 519   {"type", luaB_type},
 520   {"assert", luaB_assert},
 521   {"unpack", luaB_unpack},
 522   {"rawequal", luaB_rawequal},
 523   {"rawget", luaB_rawget},
 524   {"rawset", luaB_rawset},
 525   {"pcall", luaB_pcall},
 526   {"xpcall", luaB_xpcall},
 527   {"collectgarbage", luaB_collectgarbage},
 528   {"gcinfo", luaB_gcinfo},
 529   {"loadfile", luaB_loadfile},
 530   {"dofile", luaB_dofile},
 531   {"loadstring", luaB_loadstring},
 532   {"require", luaB_require},
 533   {NULL, NULL}
 534 };
 535
 536
 537 /*
 538 ** {======================================================
 539 ** Coroutine library
 540 ** =======================================================
 541 */
 542
 543 static int auxresume (lua_State *L, lua_State *co, int narg) {
 544   int status;
 545   if (!lua_checkstack(co, narg))
 546     luaL_error(L, "too many arguments to resume");
 547   lua_xmove(L, co, narg);
 548   status = lua_resume(co, narg);
 549   if (status == 0) {
 550     int nres = lua_gettop(co);
 551     if (!lua_checkstack(L, nres))
 552       luaL_error(L, "too many results to resume");
 553     lua_xmove(co, L, nres);  /* move yielded values */
 554     return nres;
 555   }
 556   else {
 557     lua_xmove(co, L, 1);  /* move error message */
 558     return -1;  /* error flag */
 559   }
 560 }
 561
 562
 563 static int luaB_coresume (lua_State *L) {
 564   lua_State *co = lua_tothread(L, 1);
 565   int r;
 566   luaL_argcheck(L, co, 1, "coroutine expected");
 567   r = auxresume(L, co, lua_gettop(L) - 1);
 568   if (r < 0) {
 569     lua_pushboolean(L, 0);
 570     lua_insert(L, -2);
 571     return 2;  /* return false + error message */
 572   }
 573   else {
 574     lua_pushboolean(L, 1);
 575     lua_insert(L, -(r + 1));
 576     return r + 1;  /* return true + `resume' returns */
 577   }
 578 }
 579
 580
 581 static int luaB_auxwrap (lua_State *L) {
 582   lua_State *co = lua_tothread(L, lua_upvalueindex(1));
 583   int r = auxresume(L, co, lua_gettop(L));
 584   if (r < 0) {
 585     if (lua_isstring(L, -1)) {  /* error object is a string? */
 586       luaL_where(L, 1);  /* add extra info */
 587       lua_insert(L, -2);
 588       lua_concat(L, 2);
 589     }
 590     lua_error(L);  /* propagate error */
 591   }
 592   return r;
 593 }
 594
 595
 596 static int luaB_cocreate (lua_State *L) {
 597   lua_State *NL = lua_newthread(L);
 598   luaL_argcheck(L, lua_isfunction(L, 1) && !lua_iscfunction(L, 1), 1,
 599     "Lua function expected");
 600   lua_pushvalue(L, 1);  /* move function to top */
 601   lua_xmove(L, NL, 1);  /* move function from L to NL */
 602   return 1;
 603 }
 604
 605
 606 static int luaB_cowrap (lua_State *L) {
 607   luaB_cocreate(L);
 608   lua_pushcclosure(L, luaB_auxwrap, 1);
 609   return 1;
 610 }
 611
 612
 613 static int luaB_yield (lua_State *L) {
 614   return lua_yield(L, lua_gettop(L));
 615 }
 616
 617
 618 static int luaB_costatus (lua_State *L) {
 619   lua_State *co = lua_tothread(L, 1);
 620   luaL_argcheck(L, co, 1, "coroutine expected");
 621   if (L == co) lua_pushliteral(L, "running");
 622   else {
 623     lua_Debug ar;
 624     if (lua_getstack(co, 0, &ar) == 0 && lua_gettop(co) == 0)
 625       lua_pushliteral(L, "dead");
 626     else
 627       lua_pushliteral(L, "suspended");
 628   }
 629   return 1;
 630 }
 631
 632
 633 static const luaL_reg co_funcs[] = {
 634   {"create", luaB_cocreate},
 635   {"wrap", luaB_cowrap},
 636   {"resume", luaB_coresume},
 637   {"yield", luaB_yield},
 638   {"status", luaB_costatus},
 639   {NULL, NULL}
 640 };
 641
 642 /* }====================================================== */
 643
 644
 645
 646 static void base_open (lua_State *L) {
 647   lua_pushliteral(L, "_G");
 648   lua_pushvalue(L, LUA_GLOBALSINDEX);
 649   luaL_openlib(L, NULL, base_funcs, 0);  /* open lib into global table */
 650   lua_pushliteral(L, "_VERSION");
 651   lua_pushliteral(L, LUA_VERSION);
 652   lua_rawset(L, -3);  /* set global _VERSION */
 653   /* `newproxy' needs a weaktable as upvalue */
 654   lua_pushliteral(L, "newproxy");
 655   lua_newtable(L);  /* new table `w' */
 656   lua_pushvalue(L, -1);  /* `w' will be its own metatable */
 657   lua_setmetatable(L, -2);
 658   lua_pushliteral(L, "__mode");
 659   lua_pushliteral(L, "k");
 660   lua_rawset(L, -3);  /* metatable(w).__mode = "k" */
 661   lua_pushcclosure(L, luaB_newproxy, 1);
 662   lua_rawset(L, -3);  /* set global `newproxy' */
 663   lua_rawset(L, -1);  /* set global _G */
 664 }
 665
 666
 667 LUALIB_API int luaopen_base (lua_State *L) {
 668   base_open(L);
 669   luaL_openlib(L, LUA_COLIBNAME, co_funcs, 0);
 670   lua_newtable(L);
 671   lua_setglobal(L, REQTAB);
 672   return 0;
 673 }
 674