?login_element?

Subversion Repositories NedoOS

Rev

Blame | Last modification | View Log | Download | RSS feed

  1. /*
  2. ** $Id: lua.c $
  3. ** Lua stand-alone interpreter
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7. #define lua_c
  8.  
  9. #include "lprefix.h"
  10.  
  11.  
  12. #include <stdio.h>
  13. #include <stdlib.h>
  14. #include <string.h>
  15.  
  16. #include <signal.h>
  17.  
  18. #include "lua.h"
  19.  
  20. #include "lauxlib.h"
  21. #include "lualib.h"
  22.  
  23.  
  24. #if !defined(LUA_PROGNAME)
  25. #define LUA_PROGNAME            "lua"
  26. #endif
  27.  
  28. #if !defined(LUA_INIT_VAR)
  29. #define LUA_INIT_VAR            "LUA_INIT"
  30. #endif
  31.  
  32. #define LUA_INITVARVERSION      LUA_INIT_VAR LUA_VERSUFFIX
  33.  
  34.  
  35. static lua_State *globalL = NULL;
  36.  
  37. static const char *progname = LUA_PROGNAME;
  38.  
  39.  
  40. #if defined(LUA_USE_POSIX)   /* { */
  41.  
  42. /*
  43. ** Use 'sigaction' when available.
  44. */
  45. static void setsignal (int sig, void (*handler)(int)) {
  46.   struct sigaction sa;
  47.   sa.sa_handler = handler;
  48.   sa.sa_flags = 0;
  49.   sigemptyset(&sa.sa_mask);  /* do not mask any signal */
  50.   sigaction(sig, &sa, NULL);
  51. }
  52.  
  53. #else           /* }{ */
  54.  
  55. #define setsignal            signal
  56.  
  57. #endif                               /* } */
  58.  
  59.  
  60. /*
  61. ** Hook set by signal function to stop the interpreter.
  62. */
  63. static void lstop (lua_State *L, lua_Debug *ar) {
  64.   (void)ar;  /* unused arg. */
  65.   lua_sethook(L, NULL, 0, 0);  /* reset hook */
  66.   luaL_error(L, "interrupted!");
  67. }
  68.  
  69.  
  70. /*
  71. ** Function to be called at a C signal. Because a C signal cannot
  72. ** just change a Lua state (as there is no proper synchronization),
  73. ** this function only sets a hook that, when called, will stop the
  74. ** interpreter.
  75. */
  76. static void laction (int i) {
  77.   int flag = LUA_MASKCALL | LUA_MASKRET | LUA_MASKLINE | LUA_MASKCOUNT;
  78.   setsignal(i, SIG_DFL); /* if another SIGINT happens, terminate process */
  79.   lua_sethook(globalL, lstop, flag, 1);
  80. }
  81.  
  82.  
  83. static void print_usage (const char *badoption) {
  84.   lua_writestringerror("%s: ", progname);
  85.   if (badoption[1] == 'e' || badoption[1] == 'l')
  86.     lua_writestringerror("'%s' needs argument\n", badoption);
  87.   else
  88.     lua_writestringerror("unrecognized option '%s'\n", badoption);
  89.   lua_writestringerror(
  90.   "usage: %s [options] [script [args]]\n"
  91.   "Available options are:\n"
  92.   "  -e stat   execute string 'stat'\n"
  93.   "  -i        enter interactive mode after executing 'script'\n"
  94.   "  -l mod    require library 'mod' into global 'mod'\n"
  95.   "  -l g=mod  require library 'mod' into global 'g'\n"
  96.   "  -v        show version information\n"
  97.   "  -E        ignore environment variables\n"
  98.   "  -W        turn warnings on\n"
  99.   "  --        stop handling options\n"
  100.   "  -         stop handling options and execute stdin\n"
  101.   ,
  102.   progname);
  103. }
  104.  
  105.  
  106. /*
  107. ** Prints an error message, adding the program name in front of it
  108. ** (if present)
  109. */
  110. static void l_message (const char *pname, const char *msg) {
  111.   if (pname) lua_writestringerror("%s: ", pname);
  112.   lua_writestringerror("%s\n", msg);
  113. }
  114.  
  115.  
  116. /*
  117. ** Check whether 'status' is not OK and, if so, prints the error
  118. ** message on the top of the stack. It assumes that the error object
  119. ** is a string, as it was either generated by Lua or by 'msghandler'.
  120. */
  121. static int report (lua_State *L, int status) {
  122.   if (status != LUA_OK) {
  123.     const char *msg = lua_tostring(L, -1);
  124.     l_message(progname, msg);
  125.     lua_pop(L, 1);  /* remove message */
  126.   }
  127.   return status;
  128. }
  129.  
  130.  
  131. /*
  132. ** Message handler used to run all chunks
  133. */
  134. static int msghandler (lua_State *L) {
  135.   const char *msg = lua_tostring(L, 1);
  136.   if (msg == NULL) {  /* is error object not a string? */
  137.     if (luaL_callmeta(L, 1, "__tostring") &&  /* does it have a metamethod */
  138.         lua_type(L, -1) == LUA_TSTRING)  /* that produces a string? */
  139.       return 1;  /* that is the message */
  140.     else
  141.       msg = lua_pushfstring(L, "(error object is a %s value)",
  142.                                luaL_typename(L, 1));
  143.   }
  144.   luaL_traceback(L, L, msg, 1);  /* append a standard traceback */
  145.   return 1;  /* return the traceback */
  146. }
  147.  
  148.  
  149. /*
  150. ** Interface to 'lua_pcall', which sets appropriate message function
  151. ** and C-signal handler. Used to run all chunks.
  152. */
  153. static int docall (lua_State *L, int narg, int nres) {
  154.   int status;
  155.   int base = lua_gettop(L) - narg;  /* function index */
  156.   lua_pushcfunction(L, msghandler);  /* push message handler */
  157.   lua_insert(L, base);  /* put it under function and args */
  158.   globalL = L;  /* to be available to 'laction' */
  159.   setsignal(SIGINT, laction);  /* set C-signal handler */
  160.   status = lua_pcall(L, narg, nres, base);
  161.   setsignal(SIGINT, SIG_DFL); /* reset C-signal handler */
  162.   lua_remove(L, base);  /* remove message handler from the stack */
  163.   return status;
  164. }
  165.  
  166.  
  167. static void print_version (void) {
  168.   lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
  169.   lua_writeline();
  170. }
  171.  
  172.  
  173. /*
  174. ** Create the 'arg' table, which stores all arguments from the
  175. ** command line ('argv'). It should be aligned so that, at index 0,
  176. ** it has 'argv[script]', which is the script name. The arguments
  177. ** to the script (everything after 'script') go to positive indices;
  178. ** other arguments (before the script name) go to negative indices.
  179. ** If there is no script name, assume interpreter's name as base.
  180. */
  181. static void createargtable (lua_State *L, char **argv, int argc, int script) {
  182.   int i, narg;
  183.   if (script == argc) script = 0;  /* no script name? */
  184.   narg = argc - (script + 1);  /* number of positive indices */
  185.   lua_createtable(L, narg, script + 1);
  186.   for (i = 0; i < argc; i++) {
  187.     lua_pushstring(L, argv[i]);
  188.     lua_rawseti(L, -2, i - script);
  189.   }
  190.   lua_setglobal(L, "arg");
  191. }
  192.  
  193.  
  194. static int dochunk (lua_State *L, int status) {
  195.   if (status == LUA_OK) status = docall(L, 0, 0);
  196.   return report(L, status);
  197. }
  198.  
  199.  
  200. static int dofile (lua_State *L, const char *name) {
  201.   return dochunk(L, luaL_loadfile(L, name));
  202. }
  203.  
  204.  
  205. static int dostring (lua_State *L, const char *s, const char *name) {
  206.   return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name));
  207. }
  208.  
  209.  
  210. /*
  211. ** Receives 'globname[=modname]' and runs 'globname = require(modname)'.
  212. */
  213. static int dolibrary (lua_State *L, char *globname) {
  214.   int status;
  215.   char *modname = strchr(globname, '=');
  216.   if (modname == NULL)  /* no explicit name? */
  217.     modname = globname;  /* module name is equal to global name */
  218.   else {
  219.     *modname = '\0';  /* global name ends here */
  220.     modname++;  /* module name starts after the '=' */
  221.   }
  222.   lua_getglobal(L, "require");
  223.   lua_pushstring(L, modname);
  224.   status = docall(L, 1, 1);  /* call 'require(modname)' */
  225.   if (status == LUA_OK)
  226.     lua_setglobal(L, globname);  /* globname = require(modname) */
  227.   return report(L, status);
  228. }
  229.  
  230.  
  231. /*
  232. ** Push on the stack the contents of table 'arg' from 1 to #arg
  233. */
  234. static int pushargs (lua_State *L) {
  235.   int i, n;
  236.   if (lua_getglobal(L, "arg") != LUA_TTABLE)
  237.     luaL_error(L, "'arg' is not a table");
  238.   n = (int)luaL_len(L, -1);
  239.   luaL_checkstack(L, n + 3, "too many arguments to script");
  240.   for (i = 1; i <= n; i++)
  241.     lua_rawgeti(L, -i, i);
  242.   lua_remove(L, -i);  /* remove table from the stack */
  243.   return n;
  244. }
  245.  
  246.  
  247. static int handle_script (lua_State *L, char **argv) {
  248.   int status;
  249.   const char *fname = argv[0];
  250.   if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
  251.     fname = NULL;  /* stdin */
  252.   status = luaL_loadfile(L, fname);
  253.   if (status == LUA_OK) {
  254.     int n = pushargs(L);  /* push arguments to script */
  255.     status = docall(L, n, LUA_MULTRET);
  256.   }
  257.   return report(L, status);
  258. }
  259.  
  260.  
  261. /* bits of various argument indicators in 'args' */
  262. #define has_error       1       /* bad option */
  263. #define has_i           2       /* -i */
  264. #define has_v           4       /* -v */
  265. #define has_e           8       /* -e */
  266. #define has_E           16      /* -E */
  267.  
  268.  
  269. /*
  270. ** Traverses all arguments from 'argv', returning a mask with those
  271. ** needed before running any Lua code (or an error code if it finds
  272. ** any invalid argument). 'first' returns the first not-handled argument
  273. ** (either the script name or a bad argument in case of error).
  274. */
  275. static int collectargs (char **argv, int *first) {
  276.   int args = 0;
  277.   int i;
  278.   for (i = 1; argv[i] != NULL; i++) {
  279.     *first = i;
  280.     if (argv[i][0] != '-')  /* not an option? */
  281.         return args;  /* stop handling options */
  282.     switch (argv[i][1]) {  /* else check option */
  283.       case '-':  /* '--' */
  284.         if (argv[i][2] != '\0')  /* extra characters after '--'? */
  285.           return has_error;  /* invalid option */
  286.         *first = i + 1;
  287.         return args;
  288.       case '\0':  /* '-' */
  289.         return args;  /* script "name" is '-' */
  290.       case 'E':
  291.         if (argv[i][2] != '\0')  /* extra characters? */
  292.           return has_error;  /* invalid option */
  293.         args |= has_E;
  294.         break;
  295.       case 'W':
  296.         if (argv[i][2] != '\0')  /* extra characters? */
  297.           return has_error;  /* invalid option */
  298.         break;
  299.       case 'i':
  300.         args |= has_i;  /* (-i implies -v) *//* FALLTHROUGH */
  301.       case 'v':
  302.         if (argv[i][2] != '\0')  /* extra characters? */
  303.           return has_error;  /* invalid option */
  304.         args |= has_v;
  305.         break;
  306.       case 'e':
  307.         args |= has_e;  /* FALLTHROUGH */
  308.       case 'l':  /* both options need an argument */
  309.         if (argv[i][2] == '\0') {  /* no concatenated argument? */
  310.           i++;  /* try next 'argv' */
  311.           if (argv[i] == NULL || argv[i][0] == '-')
  312.             return has_error;  /* no next argument or it is another option */
  313.         }
  314.         break;
  315.       default:  /* invalid option */
  316.         return has_error;
  317.     }
  318.   }
  319.   *first = i;  /* no script name */
  320.   return args;
  321. }
  322.  
  323.  
  324. /*
  325. ** Processes options 'e' and 'l', which involve running Lua code, and
  326. ** 'W', which also affects the state.
  327. ** Returns 0 if some code raises an error.
  328. */
  329. static int runargs (lua_State *L, char **argv, int n) {
  330.   int i;
  331.   for (i = 1; i < n; i++) {
  332.     int option = argv[i][1];
  333.     lua_assert(argv[i][0] == '-');  /* already checked */
  334.     switch (option) {
  335.       case 'e':  case 'l': {
  336.         int status;
  337.         char *extra = argv[i] + 2;  /* both options need an argument */
  338.         if (*extra == '\0') extra = argv[++i];
  339.         lua_assert(extra != NULL);
  340.         status = (option == 'e')
  341.                  ? dostring(L, extra, "=(command line)")
  342.                  : dolibrary(L, extra);
  343.         if (status != LUA_OK) return 0;
  344.         break;
  345.       }
  346.       case 'W':
  347.         lua_warning(L, "@on", 0);  /* warnings on */
  348.         break;
  349.     }
  350.   }
  351.   return 1;
  352. }
  353.  
  354.  
  355. static int handle_luainit (lua_State *L) {
  356.   const char *name = "=" LUA_INITVARVERSION;
  357.   const char *init = getenv(name + 1);
  358.   if (init == NULL) {
  359.     name = "=" LUA_INIT_VAR;
  360.     init = getenv(name + 1);  /* try alternative name */
  361.   }
  362.   if (init == NULL) return LUA_OK;
  363.   else if (init[0] == '@')
  364.     return dofile(L, init+1);
  365.   else
  366.     return dostring(L, init, name);
  367. }
  368.  
  369.  
  370. /*
  371. ** {==================================================================
  372. ** Read-Eval-Print Loop (REPL)
  373. ** ===================================================================
  374. */
  375.  
  376. #if !defined(LUA_PROMPT)
  377. #define LUA_PROMPT              "> "
  378. #define LUA_PROMPT2             ">> "
  379. #endif
  380.  
  381. #if !defined(LUA_MAXINPUT)
  382. #define LUA_MAXINPUT            512
  383. #endif
  384.  
  385.  
  386. /*
  387. ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
  388. ** is, whether we're running lua interactively).
  389. */
  390. #if !defined(lua_stdin_is_tty)  /* { */
  391.  
  392. #if defined(LUA_USE_POSIX)      /* { */
  393.  
  394. #include <unistd.h>
  395. #define lua_stdin_is_tty()      isatty(0)
  396.  
  397. #elif defined(LUA_USE_WINDOWS)  /* }{ */
  398.  
  399. #include <io.h>
  400. #include <windows.h>
  401.  
  402. #define lua_stdin_is_tty()      _isatty(_fileno(stdin))
  403.  
  404. #else                           /* }{ */
  405.  
  406. /* ISO C definition */
  407. #define lua_stdin_is_tty()      1  /* assume stdin is a tty */
  408.  
  409. #endif                          /* } */
  410.  
  411. #endif                          /* } */
  412.  
  413.  
  414. /*
  415. ** lua_readline defines how to show a prompt and then read a line from
  416. ** the standard input.
  417. ** lua_saveline defines how to "save" a read line in a "history".
  418. ** lua_freeline defines how to free a line read by lua_readline.
  419. */
  420. #if !defined(lua_readline)      /* { */
  421.  
  422. #if defined(LUA_USE_READLINE)   /* { */
  423.  
  424. #include <readline/readline.h>
  425. #include <readline/history.h>
  426. #define lua_initreadline(L)     ((void)L, rl_readline_name="lua")
  427. #define lua_readline(L,b,p)     ((void)L, ((b)=readline(p)) != NULL)
  428. #define lua_saveline(L,line)    ((void)L, add_history(line))
  429. #define lua_freeline(L,b)       ((void)L, free(b))
  430.  
  431. #else                           /* }{ */
  432.  
  433. #define lua_initreadline(L)  ((void)L)
  434. #define lua_readline(L,b,p) \
  435.         ((void)L, fputs(p, stdout), fflush(stdout),  /* show prompt */ \
  436.         fgets(b, LUA_MAXINPUT, stdin) != NULL)  /* get line */
  437. #define lua_saveline(L,line)    { (void)L; (void)line; }
  438. #define lua_freeline(L,b)       { (void)L; (void)b; }
  439.  
  440. #endif                          /* } */
  441.  
  442. #endif                          /* } */
  443.  
  444.  
  445. /*
  446. ** Return the string to be used as a prompt by the interpreter. Leave
  447. ** the string (or nil, if using the default value) on the stack, to keep
  448. ** it anchored.
  449. */
  450. static const char *get_prompt (lua_State *L, int firstline) {
  451.   if (lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2") == LUA_TNIL)
  452.     return (firstline ? LUA_PROMPT : LUA_PROMPT2);  /* use the default */
  453.   else {  /* apply 'tostring' over the value */
  454.     const char *p = luaL_tolstring(L, -1, NULL);
  455.     lua_remove(L, -2);  /* remove original value */
  456.     return p;
  457.   }
  458. }
  459.  
  460. /* mark in error messages for incomplete statements */
  461. #define EOFMARK         "<eof>"
  462. #define marklen         (sizeof(EOFMARK)/sizeof(char) - 1)
  463.  
  464.  
  465. /*
  466. ** Check whether 'status' signals a syntax error and the error
  467. ** message at the top of the stack ends with the above mark for
  468. ** incomplete statements.
  469. */
  470. static int incomplete (lua_State *L, int status) {
  471.   if (status == LUA_ERRSYNTAX) {
  472.     size_t lmsg;
  473.     const char *msg = lua_tolstring(L, -1, &lmsg);
  474.     if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {
  475.       lua_pop(L, 1);
  476.       return 1;
  477.     }
  478.   }
  479.   return 0;  /* else... */
  480. }
  481.  
  482.  
  483. /*
  484. ** Prompt the user, read a line, and push it into the Lua stack.
  485. */
  486. static int pushline (lua_State *L, int firstline) {
  487.   char buffer[LUA_MAXINPUT];
  488.   char *b = buffer;
  489.   size_t l;
  490.   const char *prmt = get_prompt(L, firstline);
  491.   int readstatus = lua_readline(L, b, prmt);
  492.   if (readstatus == 0)
  493.     return 0;  /* no input (prompt will be popped by caller) */
  494.   lua_pop(L, 1);  /* remove prompt */
  495.   l = strlen(b);
  496.   if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */
  497.     b[--l] = '\0';  /* remove it */
  498.   if (firstline && b[0] == '=')  /* for compatibility with 5.2, ... */
  499.     lua_pushfstring(L, "return %s", b + 1);  /* change '=' to 'return' */
  500.   else
  501.     lua_pushlstring(L, b, l);
  502.   lua_freeline(L, b);
  503.   return 1;
  504. }
  505.  
  506.  
  507. /*
  508. ** Try to compile line on the stack as 'return <line>;'; on return, stack
  509. ** has either compiled chunk or original line (if compilation failed).
  510. */
  511. static int addreturn (lua_State *L) {
  512.   const char *line = lua_tostring(L, -1);  /* original line */
  513.   const char *retline = lua_pushfstring(L, "return %s;", line);
  514.   int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin");
  515.   if (status == LUA_OK) {
  516.     lua_remove(L, -2);  /* remove modified line */
  517.     if (line[0] != '\0')  /* non empty? */
  518.       lua_saveline(L, line);  /* keep history */
  519.   }
  520.   else
  521.     lua_pop(L, 2);  /* pop result from 'luaL_loadbuffer' and modified line */
  522.   return status;
  523. }
  524.  
  525.  
  526. /*
  527. ** Read multiple lines until a complete Lua statement
  528. */
  529. static int multiline (lua_State *L) {
  530.   for (;;) {  /* repeat until gets a complete statement */
  531.     size_t len;
  532.     const char *line = lua_tolstring(L, 1, &len);  /* get what it has */
  533.     int status = luaL_loadbuffer(L, line, len, "=stdin");  /* try it */
  534.     if (!incomplete(L, status) || !pushline(L, 0)) {
  535.       lua_saveline(L, line);  /* keep history */
  536.       return status;  /* cannot or should not try to add continuation line */
  537.     }
  538.     lua_pushliteral(L, "\n");  /* add newline... */
  539.     lua_insert(L, -2);  /* ...between the two lines */
  540.     lua_concat(L, 3);  /* join them */
  541.   }
  542. }
  543.  
  544.  
  545. /*
  546. ** Read a line and try to load (compile) it first as an expression (by
  547. ** adding "return " in front of it) and second as a statement. Return
  548. ** the final status of load/call with the resulting function (if any)
  549. ** in the top of the stack.
  550. */
  551. static int loadline (lua_State *L) {
  552.   int status;
  553.   lua_settop(L, 0);
  554.   if (!pushline(L, 1))
  555.     return -1;  /* no input */
  556.   if ((status = addreturn(L)) != LUA_OK)  /* 'return ...' did not work? */
  557.     status = multiline(L);  /* try as command, maybe with continuation lines */
  558.   lua_remove(L, 1);  /* remove line from the stack */
  559.   lua_assert(lua_gettop(L) == 1);
  560.   return status;
  561. }
  562.  
  563.  
  564. /*
  565. ** Prints (calling the Lua 'print' function) any values on the stack
  566. */
  567. static void l_print (lua_State *L) {
  568.   int n = lua_gettop(L);
  569.   if (n > 0) {  /* any result to be printed? */
  570.     luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
  571.     lua_getglobal(L, "print");
  572.     lua_insert(L, 1);
  573.     if (lua_pcall(L, n, 0, 0) != LUA_OK)
  574.       l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)",
  575.                                              lua_tostring(L, -1)));
  576.   }
  577. }
  578.  
  579.  
  580. /*
  581. ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
  582. ** print any results.
  583. */
  584. static void doREPL (lua_State *L) {
  585.   int status;
  586.   const char *oldprogname = progname;
  587.   progname = NULL;  /* no 'progname' on errors in interactive mode */
  588.   lua_initreadline(L);
  589.   while ((status = loadline(L)) != -1) {
  590.     if (status == LUA_OK)
  591.       status = docall(L, 0, LUA_MULTRET);
  592.     if (status == LUA_OK) l_print(L);
  593.     else report(L, status);
  594.   }
  595.   lua_settop(L, 0);  /* clear stack */
  596.   lua_writeline();
  597.   progname = oldprogname;
  598. }
  599.  
  600. /* }================================================================== */
  601.  
  602.  
  603. /*
  604. ** Main body of stand-alone interpreter (to be called in protected mode).
  605. ** Reads the options and handles them all.
  606. */
  607. static int pmain (lua_State *L) {
  608.   int argc = (int)lua_tointeger(L, 1);
  609.   char **argv = (char **)lua_touserdata(L, 2);
  610.   int script;
  611.   int args = collectargs(argv, &script);
  612.   luaL_checkversion(L);  /* check that interpreter has correct version */
  613.   if (argv[0] && argv[0][0]) progname = argv[0];
  614.   if (args == has_error) {  /* bad arg? */
  615.     print_usage(argv[script]);  /* 'script' has index of bad arg. */
  616.     return 0;
  617.   }
  618.   if (args & has_v)  /* option '-v'? */
  619.     print_version();
  620.   if (args & has_E) {  /* option '-E'? */
  621.     lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
  622.     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
  623.   }
  624.   luaL_openlibs(L);  /* open standard libraries */
  625.   createargtable(L, argv, argc, script);  /* create table 'arg' */
  626.   lua_gc(L, LUA_GCGEN, 0, 0);  /* GC in generational mode */
  627.   if (!(args & has_E)) {  /* no option '-E'? */
  628.     if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */
  629.       return 0;  /* error running LUA_INIT */
  630.   }
  631.   if (!runargs(L, argv, script))  /* execute arguments -e and -l */
  632.     return 0;  /* something failed */
  633.   if (script < argc &&  /* execute main script (if there is one) */
  634.       handle_script(L, argv + script) != LUA_OK)
  635.     return 0;
  636.   if (args & has_i)  /* -i option? */
  637.     doREPL(L);  /* do read-eval-print loop */
  638.   else if (script == argc && !(args & (has_e | has_v))) {  /* no arguments? */
  639.     if (lua_stdin_is_tty()) {  /* running in interactive mode? */
  640.       print_version();
  641.       doREPL(L);  /* do read-eval-print loop */
  642.     }
  643.     else dofile(L, NULL);  /* executes stdin as a file */
  644.   }
  645.   lua_pushboolean(L, 1);  /* signal no errors */
  646.   return 1;
  647. }
  648.  
  649.  
  650. int main (int argc, char **argv) {
  651.   int status, result;
  652.   lua_State *L = luaL_newstate();  /* create state */
  653.   if (L == NULL) {
  654.     l_message(argv[0], "cannot create state: not enough memory");
  655.     return EXIT_FAILURE;
  656.   }
  657.   lua_pushcfunction(L, &pmain);  /* to call 'pmain' in protected mode */
  658.   lua_pushinteger(L, argc);  /* 1st argument */
  659.   lua_pushlightuserdata(L, argv); /* 2nd argument */
  660.   status = lua_pcall(L, 2, 1, 0);  /* do the call */
  661.   result = lua_toboolean(L, -1);  /* get result */
  662.   report(L, status);
  663.   lua_close(L);
  664.   return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
  665. }
  666.  
  667.