Upgrading to Lua-5.1.2

1 files changed, 612 insertions, 153 deletions

diff --git a/lib/lua/src/LuaLib/loadlib.c b/lib/lua/src/LuaLib/loadlib.c
index 8756205..5c6019f 100644
--- a/lib/lua/src/LuaLib/loadlib.c
+++ b/lib/lua/src/LuaLib/loadlib.c
@@ -1,205 +1,664 @@
 /*
-** $Id: loadlib.c,v 1.4 2004-11-27 21:46:10 pixel Exp $
+** $Id: loadlib.c,v 1.5 2007-07-27 10:05:55 pixel Exp $
 ** Dynamic library loader for Lua
 ** See Copyright Notice in lua.h
-*
-* This  Lua library  exports a  single function,  called loadlib,  which is
-* called from Lua  as loadlib(lib,init), where lib is the  full name of the
-* library to be  loaded (including the complete path) and  init is the name
-* of a function  to be called after the library  is loaded. Typically, this
-* function will register other functions,  thus making the complete library
-* available  to Lua.  The init  function is  *not* automatically  called by
-* loadlib. Instead,  loadlib returns  the init function  as a  Lua function
-* that the client  can call when it  thinks is appropriate. In  the case of
-* errors,  loadlib  returns  nil  and two  strings  describing  the  error.
-* The  first string  is  supplied by  the operating  system;  it should  be
-* informative and useful  for error messages. The second  string is "open",
-* "init", or  "absent" to identify  the error and is  meant to be  used for
-* making  decisions without  having to  look into  the first  string (whose
-* format is system-dependent).
-*
-* This module contains  an implementation of loadlib for  Unix systems that
-* have dlfcn, an implementation for Windows,  and a stub for other systems.
-* See  the list  at  the end  of  this  file for  some  links to  available
-* implementations of dlfcn  and interfaces to other  native dynamic loaders
-* on top of which loadlib could be implemented.
-*
+**
+** This module contains an implementation of loadlib for Unix systems
+** that have dlfcn, an implementation for Darwin (Mac OS X), an
+** implementation for Windows, and a stub for other systems.
 */
 
+
+#include <stdlib.h>
+#include <string.h>
+
+
+#define loadlib_c
+#define LUA_LIB
+
 #include "lua.h"
+
 #include "lauxlib.h"
 #include "lualib.h"
 
 
-#undef LOADLIB
+/* prefix for open functions in C libraries */
+#define LUA_POF		"luaopen_"
+
+/* separator for open functions in C libraries */
+#define LUA_OFSEP	"_"
+
+
+#define LIBPREFIX	"LOADLIB: "
+
+#define POF		LUA_POF
+#define LIB_FAIL	"open"
+
+
+/* error codes for ll_loadfunc */
+#define ERRLIB		1
+#define ERRFUNC		2
 
+#define setprogdir(L)		((void)0)
 
-#ifdef USE_DLOPEN
-#define LOADLIB
+
+static void ll_unloadlib (void *lib);
+static void *ll_load (lua_State *L, const char *path);
+static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym);
+
+
+
+#if defined(LUA_DL_DLOPEN)
 /*
-* This is an implementation of loadlib based on the dlfcn interface.
-* The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
-* NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
-* as an emulation layer on top of native functions.
+** {========================================================================
+** This is an implementation of loadlib based on the dlfcn interface.
+** The dlfcn interface is available in Linux, SunOS, Solaris, IRIX, FreeBSD,
+** NetBSD, AIX 4.2, HPUX 11, and  probably most other Unix flavors, at least
+** as an emulation layer on top of native functions.
+** =========================================================================
 */
 
 #include <dlfcn.h>
 
-static int loadlib(lua_State *L)
-{
- const char *path=luaL_checkstring(L,1);
- const char *init=luaL_checkstring(L,2);
- void *lib=dlopen(path,RTLD_NOW);
- if (lib!=NULL)
- {
-  lua_CFunction f=(lua_CFunction) dlsym(lib,init);
-  if (f!=NULL)
-  {
-   lua_pushlightuserdata(L,lib);
-   lua_pushcclosure(L,f,1);
-   return 1;
-  }
- }
- /* else return appropriate error messages */
- lua_pushnil(L);
- lua_pushstring(L,dlerror());
- lua_pushstring(L,(lib!=NULL) ? "init" : "open");
- if (lib!=NULL) dlclose(lib);
- return 3;
+static void ll_unloadlib (void *lib) {
+  dlclose(lib);
 }
 
-#endif
+
+static void *ll_load (lua_State *L, const char *path) {
+  void *lib = dlopen(path, RTLD_NOW);
+  if (lib == NULL) lua_pushstring(L, dlerror());
+  return lib;
+}
+
+
+static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
+  lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
+  if (f == NULL) lua_pushstring(L, dlerror());
+  return f;
+}
+
+/* }====================================================== */
+
+
+
+#elif defined(LUA_DL_DLL)
+/*
+** {======================================================================
+** This is an implementation of loadlib for Windows using native functions.
+** =======================================================================
+*/
+
+#include <windows.h>
+
+
+#undef setprogdir
+
+static void setprogdir (lua_State *L) {
+  char buff[MAX_PATH + 1];
+  char *lb;
+  DWORD nsize = sizeof(buff)/sizeof(char);
+  DWORD n = GetModuleFileNameA(NULL, buff, nsize);
+  if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL)
+    luaL_error(L, "unable to get ModuleFileName");
+  else {
+    *lb = '\0';
+    luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
+    lua_remove(L, -2);  /* remove original string */
+  }
+}
+
+
+static void pusherror (lua_State *L) {
+  int error = GetLastError();
+  char buffer[128];
+  if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
+      NULL, error, 0, buffer, sizeof(buffer), NULL))
+    lua_pushstring(L, buffer);
+  else
+    lua_pushfstring(L, "system error %d\n", error);
+}
+
+static void ll_unloadlib (void *lib) {
+  FreeLibrary((HINSTANCE)lib);
+}
+
+
+static void *ll_load (lua_State *L, const char *path) {
+  HINSTANCE lib = LoadLibraryA(path);
+  if (lib == NULL) pusherror(L);
+  return lib;
+}
+
+
+static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
+  lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
+  if (f == NULL) pusherror(L);
+  return f;
+}
+
+/* }====================================================== */
 
 
 
+#elif defined(LUA_DL_DYLD)
 /*
-** In Windows, default is to use dll; otherwise, default is not to use dll
+** {======================================================================
+** Native Mac OS X / Darwin Implementation
+** =======================================================================
 */
-#ifndef USE_DLL
-#ifdef _WIN32
-#define USE_DLL	1
+
+#include <mach-o/dyld.h>
+
+
+/* Mac appends a `_' before C function names */
+#undef POF
+#define POF	"_" LUA_POF
+
+
+static void pusherror (lua_State *L) {
+  const char *err_str;
+  const char *err_file;
+  NSLinkEditErrors err;
+  int err_num;
+  NSLinkEditError(&err, &err_num, &err_file, &err_str);
+  lua_pushstring(L, err_str);
+}
+
+
+static const char *errorfromcode (NSObjectFileImageReturnCode ret) {
+  switch (ret) {
+    case NSObjectFileImageInappropriateFile:
+      return "file is not a bundle";
+    case NSObjectFileImageArch:
+      return "library is for wrong CPU type";
+    case NSObjectFileImageFormat:
+      return "bad format";
+    case NSObjectFileImageAccess:
+      return "cannot access file";
+    case NSObjectFileImageFailure:
+    default:
+      return "unable to load library";
+  }
+}
+
+
+static void ll_unloadlib (void *lib) {
+  NSUnLinkModule((NSModule)lib, NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES);
+}
+
+
+static void *ll_load (lua_State *L, const char *path) {
+  NSObjectFileImage img;
+  NSObjectFileImageReturnCode ret;
+  /* this would be a rare case, but prevents crashing if it happens */
+  if(!_dyld_present()) {
+    lua_pushliteral(L, "dyld not present");
+    return NULL;
+  }
+  ret = NSCreateObjectFileImageFromFile(path, &img);
+  if (ret == NSObjectFileImageSuccess) {
+    NSModule mod = NSLinkModule(img, path, NSLINKMODULE_OPTION_PRIVATE |
+                       NSLINKMODULE_OPTION_RETURN_ON_ERROR);
+    NSDestroyObjectFileImage(img);
+    if (mod == NULL) pusherror(L);
+    return mod;
+  }
+  lua_pushstring(L, errorfromcode(ret));
+  return NULL;
+}
+
+
+static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
+  NSSymbol nss = NSLookupSymbolInModule((NSModule)lib, sym);
+  if (nss == NULL) {
+    lua_pushfstring(L, "symbol " LUA_QS " not found", sym);
+    return NULL;
+  }
+  return (lua_CFunction)NSAddressOfSymbol(nss);
+}
+
+/* }====================================================== */
+
+
+
 #else
-#define USE_DLL	0
-#endif
+/*
+** {======================================================
+** Fallback for other systems
+** =======================================================
+*/
+
+#undef LIB_FAIL
+#define LIB_FAIL	"absent"
+
+
+#define DLMSG	"dynamic libraries not enabled; check your Lua installation"
+
+
+static void ll_unloadlib (void *lib) {
+  (void)lib;  /* to avoid warnings */
+}
+
+
+static void *ll_load (lua_State *L, const char *path) {
+  (void)path;  /* to avoid warnings */
+  lua_pushliteral(L, DLMSG);
+  return NULL;
+}
+
+
+static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) {
+  (void)lib; (void)sym;  /* to avoid warnings */
+  lua_pushliteral(L, DLMSG);
+  return NULL;
+}
+
+/* }====================================================== */
 #endif
 
 
-#if USE_DLL
-#define LOADLIB
+
+static void **ll_register (lua_State *L, const char *path) {
+  void **plib;
+  lua_pushfstring(L, "%s%s", LIBPREFIX, path);
+  lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
+  if (!lua_isnil(L, -1))  /* is there an entry? */
+    plib = (void **)lua_touserdata(L, -1);
+  else {  /* no entry yet; create one */
+    lua_pop(L, 1);
+    plib = (void **)lua_newuserdata(L, sizeof(const void *));
+    *plib = NULL;
+    luaL_getmetatable(L, "_LOADLIB");
+    lua_setmetatable(L, -2);
+    lua_pushfstring(L, "%s%s", LIBPREFIX, path);
+    lua_pushvalue(L, -2);
+    lua_settable(L, LUA_REGISTRYINDEX);
+  }
+  return plib;
+}
+
+
 /*
-* This is an implementation of loadlib for Windows using native functions.
+** __gc tag method: calls library's `ll_unloadlib' function with the lib
+** handle
 */
+static int gctm (lua_State *L) {
+  void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
+  if (*lib) ll_unloadlib(*lib);
+  *lib = NULL;  /* mark library as closed */
+  return 0;
+}
 
-#include <windows.h>
 
-static void pusherror(lua_State *L)
-{
- int error=GetLastError();
- char buffer[128];
- if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
-	0, error, 0, buffer, sizeof(buffer), 0))
-  lua_pushstring(L,buffer);
- else
-  lua_pushfstring(L,"system error %d\n",error);
-}
-
-static int loadlib(lua_State *L)
-{
- const char *path=luaL_checkstring(L,1);
- const char *init=luaL_checkstring(L,2);
- HINSTANCE lib=LoadLibrary(path);
- if (lib!=NULL)
- {
-  lua_CFunction f=(lua_CFunction) GetProcAddress(lib,init);
-  if (f!=NULL)
-  {
-   lua_pushlightuserdata(L,lib);
-   lua_pushcclosure(L,f,1);
-   return 1;
-  }
- }
- lua_pushnil(L);
- pusherror(L);
- lua_pushstring(L,(lib!=NULL) ? "init" : "open");
- if (lib!=NULL) FreeLibrary(lib);
- return 3;
+static int ll_loadfunc (lua_State *L, const char *path, const char *sym) {
+  void **reg = ll_register(L, path);
+  if (*reg == NULL) *reg = ll_load(L, path);
+  if (*reg == NULL)
+    return ERRLIB;  /* unable to load library */
+  else {
+    lua_CFunction f = ll_sym(L, *reg, sym);
+    if (f == NULL)
+      return ERRFUNC;  /* unable to find function */
+    lua_pushcfunction(L, f);
+    return 0;  /* return function */
+  }
 }
 
-#endif
 
+static int ll_loadlib (lua_State *L) {
+  const char *path = luaL_checkstring(L, 1);
+  const char *init = luaL_checkstring(L, 2);
+  int stat = ll_loadfunc(L, path, init);
+  if (stat == 0)  /* no errors? */
+    return 1;  /* return the loaded function */
+  else {  /* error; error message is on stack top */
+    lua_pushnil(L);
+    lua_insert(L, -2);
+    lua_pushstring(L, (stat == ERRLIB) ?  LIB_FAIL : "init");
+    return 3;  /* return nil, error message, and where */
+  }
+}
 
 
-#ifndef LOADLIB
-/* Fallback for other systems */
 
 /*
-** Those systems support dlopen, so they should have defined USE_DLOPEN.
-** The default (no)implementation gives them a special error message.
+** {======================================================
+** 'require' function
+** =======================================================
 */
-#ifdef linux
-#define LOADLIB
-#endif
 
-#ifdef sun
-#define LOADLIB
-#endif
 
-#ifdef sgi
-#define LOADLIB
-#endif
+static int readable (const char *filename) {
+  FILE *f = fopen(filename, "r");  /* try to open file */
+  if (f == NULL) return 0;  /* open failed */
+  fclose(f);
+  return 1;
+}
 
-#ifdef BSD
-#define LOADLIB
-#endif
 
-#ifdef _WIN32
-#define LOADLIB
-#endif
+static const char *pushnexttemplate (lua_State *L, const char *path) {
+  const char *l;
+  while (*path == *LUA_PATHSEP) path++;  /* skip separators */
+  if (*path == '\0') return NULL;  /* no more templates */
+  l = strchr(path, *LUA_PATHSEP);  /* find next separator */
+  if (l == NULL) l = path + strlen(path);
+  lua_pushlstring(L, path, l - path);  /* template */
+  return l;
+}
 
-#ifdef LOADLIB
-#undef LOADLIB
-#define LOADLIB	"`loadlib' not installed (check your Lua configuration)"
-#else
-#define LOADLIB	"`loadlib' not supported"
-#endif
 
-static int loadlib(lua_State *L)
-{
- lua_pushnil(L);
- lua_pushliteral(L,LOADLIB);
- lua_pushliteral(L,"absent");
- return 3;
+static const char *findfile (lua_State *L, const char *name,
+                                           const char *pname) {
+  const char *path;
+  name = luaL_gsub(L, name, ".", LUA_DIRSEP);
+  lua_getfield(L, LUA_ENVIRONINDEX, pname);
+  path = lua_tostring(L, -1);
+  if (path == NULL)
+    luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
+  lua_pushliteral(L, "");  /* error accumulator */
+  while ((path = pushnexttemplate(L, path)) != NULL) {
+    const char *filename;
+    filename = luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
+    lua_remove(L, -2);  /* remove path template */
+    if (readable(filename))  /* does file exist and is readable? */
+      return filename;  /* return that file name */
+    lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
+    lua_remove(L, -2);  /* remove file name */
+    lua_concat(L, 2);  /* add entry to possible error message */
+  }
+  return NULL;  /* not found */
 }
-#endif
 
-LUALIB_API int luaopen_loadlib (lua_State *L)
-{
- lua_register(L,"loadlib",loadlib);
- return 0;
+
+static void loaderror (lua_State *L, const char *filename) {
+  luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
+                lua_tostring(L, 1), filename, lua_tostring(L, -1));
+}
+
+
+static int loader_Lua (lua_State *L) {
+  const char *filename;
+  const char *name = luaL_checkstring(L, 1);
+  filename = findfile(L, name, "path");
+  if (filename == NULL) return 1;  /* library not found in this path */
+  if (luaL_loadfile(L, filename) != 0)
+    loaderror(L, filename);
+  return 1;  /* library loaded successfully */
+}
+
+
+static const char *mkfuncname (lua_State *L, const char *modname) {
+  const char *funcname;
+  const char *mark = strchr(modname, *LUA_IGMARK);
+  if (mark) modname = mark + 1;
+  funcname = luaL_gsub(L, modname, ".", LUA_OFSEP);
+  funcname = lua_pushfstring(L, POF"%s", funcname);
+  lua_remove(L, -2);  /* remove 'gsub' result */
+  return funcname;
+}
+
+
+static int loader_C (lua_State *L) {
+  const char *funcname;
+  const char *name = luaL_checkstring(L, 1);
+  const char *filename = findfile(L, name, "cpath");
+  if (filename == NULL) return 1;  /* library not found in this path */
+  funcname = mkfuncname(L, name);
+  if (ll_loadfunc(L, filename, funcname) != 0)
+    loaderror(L, filename);
+  return 1;  /* library loaded successfully */
+}
+
+
+static int loader_Croot (lua_State *L) {
+  const char *funcname;
+  const char *filename;
+  const char *name = luaL_checkstring(L, 1);
+  const char *p = strchr(name, '.');
+  int stat;
+  if (p == NULL) return 0;  /* is root */
+  lua_pushlstring(L, name, p - name);
+  filename = findfile(L, lua_tostring(L, -1), "cpath");
+  if (filename == NULL) return 1;  /* root not found */
+  funcname = mkfuncname(L, name);
+  if ((stat = ll_loadfunc(L, filename, funcname)) != 0) {
+    if (stat != ERRFUNC) loaderror(L, filename);  /* real error */
+    lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
+                       name, filename);
+    return 1;  /* function not found */
+  }
+  return 1;
+}
+
+
+static int loader_preload (lua_State *L) {
+  const char *name = luaL_checkstring(L, 1);
+  lua_getfield(L, LUA_ENVIRONINDEX, "preload");
+  if (!lua_istable(L, -1))
+    luaL_error(L, LUA_QL("package.preload") " must be a table");
+  lua_getfield(L, -1, name);
+  if (lua_isnil(L, -1))  /* not found? */
+    lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
+  return 1;
+}
+
+
+static const int sentinel_ = 0;
+#define sentinel	((void *)&sentinel_)
+
+
+static int ll_require (lua_State *L) {
+  const char *name = luaL_checkstring(L, 1);
+  int i;
+  lua_settop(L, 1);  /* _LOADED table will be at index 2 */
+  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
+  lua_getfield(L, 2, name);
+  if (lua_toboolean(L, -1)) {  /* is it there? */
+    if (lua_touserdata(L, -1) == sentinel)  /* check loops */
+      luaL_error(L, "loop or previous error loading module " LUA_QS, name);
+    return 1;  /* package is already loaded */
+  }
+  /* else must load it; iterate over available loaders */
+  lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
+  if (!lua_istable(L, -1))
+    luaL_error(L, LUA_QL("package.loaders") " must be a table");
+  lua_pushliteral(L, "");  /* error message accumulator */
+  for (i=1; ; i++) {
+    lua_rawgeti(L, -2, i);  /* get a loader */
+    if (lua_isnil(L, -1))
+      luaL_error(L, "module " LUA_QS " not found:%s",
+                    name, lua_tostring(L, -2));
+    lua_pushstring(L, name);
+    lua_call(L, 1, 1);  /* call it */
+    if (lua_isfunction(L, -1))  /* did it find module? */
+      break;  /* module loaded successfully */
+    else if (lua_isstring(L, -1))  /* loader returned error message? */
+      lua_concat(L, 2);  /* accumulate it */
+    else
+      lua_pop(L, 1);
+  }
+  lua_pushlightuserdata(L, sentinel);
+  lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
+  lua_pushstring(L, name);  /* pass name as argument to module */
+  lua_call(L, 1, 1);  /* run loaded module */
+  if (!lua_isnil(L, -1))  /* non-nil return? */
+    lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
+  lua_getfield(L, 2, name);
+  if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
+    lua_pushboolean(L, 1);  /* use true as result */
+    lua_pushvalue(L, -1);  /* extra copy to be returned */
+    lua_setfield(L, 2, name);  /* _LOADED[name] = true */
+  }
+  return 1;
 }
 
+/* }====================================================== */
+
+
+
 /*
-* Here are some links to available implementations of dlfcn and
-* interfaces to other native dynamic loaders on top of which loadlib
-* could be implemented. Please send contributions and corrections to us.
-*
-* AIX
-* Starting with AIX 4.2, dlfcn is included in the base OS.
-* There is also an emulation package available.
-* http://www.faqs.org/faqs/aix-faq/part4/section-21.html
-*
-* HPUX 
-* HPUX 11 has dlfcn. For HPUX 10 use shl_*.
-* http://www.geda.seul.org/mailinglist/geda-dev37/msg00094.html
-* http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html
-*
-* Macintosh, Windows
-* http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html
-*
-* Mac OS X/Darwin
-* http://www.opendarwin.org/projects/dlcompat/
-*
-* GLIB has wrapper code for BeOS, OS2, Unix and Windows
-* http://cvs.gnome.org/lxr/source/glib/gmodule/
-*
+** {======================================================
+** 'module' function
+** =======================================================
 */
+  
+
+static void setfenv (lua_State *L) {
+  lua_Debug ar;
+  lua_getstack(L, 1, &ar);
+  lua_getinfo(L, "f", &ar);
+  lua_pushvalue(L, -2);
+  lua_setfenv(L, -2);
+  lua_pop(L, 1);
+}
+
+
+static void dooptions (lua_State *L, int n) {
+  int i;
+  for (i = 2; i <= n; i++) {
+    lua_pushvalue(L, i);  /* get option (a function) */
+    lua_pushvalue(L, -2);  /* module */
+    lua_call(L, 1, 0);
+  }
+}
+
+
+static void modinit (lua_State *L, const char *modname) {
+  const char *dot;
+  lua_pushvalue(L, -1);
+  lua_setfield(L, -2, "_M");  /* module._M = module */
+  lua_pushstring(L, modname);
+  lua_setfield(L, -2, "_NAME");
+  dot = strrchr(modname, '.');  /* look for last dot in module name */
+  if (dot == NULL) dot = modname;
+  else dot++;
+  /* set _PACKAGE as package name (full module name minus last part) */
+  lua_pushlstring(L, modname, dot - modname);
+  lua_setfield(L, -2, "_PACKAGE");
+}
+
+
+static int ll_module (lua_State *L) {
+  const char *modname = luaL_checkstring(L, 1);
+  int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
+  lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
+  lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
+  if (!lua_istable(L, -1)) {  /* not found? */
+    lua_pop(L, 1);  /* remove previous result */
+    /* try global variable (and create one if it does not exist) */
+    if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
+      return luaL_error(L, "name conflict for module " LUA_QS, modname);
+    lua_pushvalue(L, -1);
+    lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
+  }
+  /* check whether table already has a _NAME field */
+  lua_getfield(L, -1, "_NAME");
+  if (!lua_isnil(L, -1))  /* is table an initialized module? */
+    lua_pop(L, 1);
+  else {  /* no; initialize it */
+    lua_pop(L, 1);
+    modinit(L, modname);
+  }
+  lua_pushvalue(L, -1);
+  setfenv(L);
+  dooptions(L, loaded - 1);
+  return 0;
+}
+
+
+static int ll_seeall (lua_State *L) {
+  luaL_checktype(L, 1, LUA_TTABLE);
+  if (!lua_getmetatable(L, 1)) {
+    lua_createtable(L, 0, 1); /* create new metatable */
+    lua_pushvalue(L, -1);
+    lua_setmetatable(L, 1);
+  }
+  lua_pushvalue(L, LUA_GLOBALSINDEX);
+  lua_setfield(L, -2, "__index");  /* mt.__index = _G */
+  return 0;
+}
+
+
+/* }====================================================== */
+
+
+
+/* auxiliary mark (for internal use) */
+#define AUXMARK		"\1"
+
+static void setpath (lua_State *L, const char *fieldname, const char *envname,
+                                   const char *def) {
+  const char *path = getenv(envname);
+  if (path == NULL)  /* no environment variable? */
+    lua_pushstring(L, def);  /* use default */
+  else {
+    /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
+    path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
+                              LUA_PATHSEP AUXMARK LUA_PATHSEP);
+    luaL_gsub(L, path, AUXMARK, def);
+    lua_remove(L, -2);
+  }
+  setprogdir(L);
+  lua_setfield(L, -2, fieldname);
+}
+
+
+static const luaL_Reg pk_funcs[] = {
+  {"loadlib", ll_loadlib},
+  {"seeall", ll_seeall},
+  {NULL, NULL}
+};
+
+
+static const luaL_Reg ll_funcs[] = {
+  {"module", ll_module},
+  {"require", ll_require},
+  {NULL, NULL}
+};
+
+
+static const lua_CFunction loaders[] =
+  {loader_preload, loader_Lua, loader_C, loader_Croot, NULL};
+
+
+LUALIB_API int luaopen_package (lua_State *L) {
+  int i;
+  /* create new type _LOADLIB */
+  luaL_newmetatable(L, "_LOADLIB");
+  lua_pushcfunction(L, gctm);
+  lua_setfield(L, -2, "__gc");
+  /* create `package' table */
+  luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
+#if defined(LUA_COMPAT_LOADLIB) 
+  lua_getfield(L, -1, "loadlib");
+  lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
+#endif
+  lua_pushvalue(L, -1);
+  lua_replace(L, LUA_ENVIRONINDEX);
+  /* create `loaders' table */
+  lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
+  /* fill it with pre-defined loaders */
+  for (i=0; loaders[i] != NULL; i++) {
+    lua_pushcfunction(L, loaders[i]);
+    lua_rawseti(L, -2, i+1);
+  }
+  lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
+  setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
+  setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
+  /* store config information */
+  lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
+                     LUA_EXECDIR "\n" LUA_IGMARK);
+  lua_setfield(L, -2, "config");
+  /* set field `loaded' */
+  luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
+  lua_setfield(L, -2, "loaded");
+  /* set field `preload' */
+  lua_newtable(L);
+  lua_setfield(L, -2, "preload");
+  lua_pushvalue(L, LUA_GLOBALSINDEX);
+  luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
+  lua_pop(L, 1);
+  return 1;  /* return 'package' table */
+}
+