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** $Id: lua.c,v 1.160.1.2 2007/12/28 15:32:23 roberto Exp $
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** Lua stand-alone interpreter
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** See Copyright Notice in lua.h
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static lua_State *globalL = NULL;
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static const char *progname = LUA_PROGNAME;
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static void lstop (lua_State *L, lua_Debug *ar) {
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(void)ar; /* unused arg. */
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lua_sethook(L, NULL, 0, 0);
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luaL_error(L, "interrupted!");
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static void laction (int i) {
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signal(i, SIG_DFL); /* if another SIGINT happens before lstop,
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terminate process (default action) */
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lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
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static void print_usage (void) {
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"usage: %s [options] [script [args]].\n"
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"Available options are:\n"
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" -e stat execute string " LUA_QL("stat") "\n"
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" -l name require library " LUA_QL("name") "\n"
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" -i enter interactive mode after executing " LUA_QL("script") "\n"
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" -v show version information\n"
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" -- stop handling options\n"
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" - execute stdin and stop handling options\n"
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static void l_message (const char *pname, const char *msg) {
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if (pname) fprintf(stderr, "%s: ", pname);
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fprintf(stderr, "%s\n", msg);
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static int report (lua_State *L, int status) {
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if (status && !lua_isnil(L, -1)) {
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const char *msg = lua_tostring(L, -1);
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if (msg == NULL) msg = "(error object is not a string)";
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l_message(progname, msg);
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static int traceback (lua_State *L) {
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if (!lua_isstring(L, 1)) /* 'message' not a string? */
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return 1; /* keep it intact */
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lua_getfield(L, LUA_GLOBALSINDEX, "debug");
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if (!lua_istable(L, -1)) {
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lua_getfield(L, -1, "traceback");
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if (!lua_isfunction(L, -1)) {
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lua_pushvalue(L, 1); /* pass error message */
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lua_pushinteger(L, 2); /* skip this function and traceback */
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lua_call(L, 2, 1); /* call debug.traceback */
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static int docall (lua_State *L, int narg, int clear) {
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int base = lua_gettop(L) - narg; /* function index */
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lua_pushcfunction(L, traceback); /* push traceback function */
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lua_insert(L, base); /* put it under chunk and args */
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signal(SIGINT, laction);
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status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base);
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signal(SIGINT, SIG_DFL);
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lua_remove(L, base); /* remove traceback function */
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/* force a complete garbage collection in case of errors */
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if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0);
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static void print_version (void) {
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l_message(NULL, LUA_RELEASE " " LUA_COPYRIGHT);
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static int getargs (lua_State *L, char **argv, int n) {
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while (argv[argc]) argc++; /* count total number of arguments */
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narg = argc - (n + 1); /* number of arguments to the script */
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luaL_checkstack(L, narg + 3, "too many arguments to script");
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for (i=n+1; i < argc; i++)
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lua_pushstring(L, argv[i]);
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lua_createtable(L, narg, n + 1);
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for (i=0; i < argc; i++) {
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lua_pushstring(L, argv[i]);
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lua_rawseti(L, -2, i - n);
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static int dofile (lua_State *L, const char *name) {
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int status = luaL_loadfile(L, name) || docall(L, 0, 1);
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return report(L, status);
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static int dostring (lua_State *L, const char *s, const char *name) {
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int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1);
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return report(L, status);
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static int dolibrary (lua_State *L, const char *name) {
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lua_getglobal(L, "require");
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lua_pushstring(L, name);
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return report(L, docall(L, 1, 1));
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static const char *get_prompt (lua_State *L, int firstline) {
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lua_getfield(L, LUA_GLOBALSINDEX, firstline ? "_PROMPT" : "_PROMPT2");
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p = lua_tostring(L, -1);
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if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
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lua_pop(L, 1); /* remove global */
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static int incomplete (lua_State *L, int status) {
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if (status == LUA_ERRSYNTAX) {
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const char *msg = lua_tolstring(L, -1, &lmsg);
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const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
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if (strstr(msg, LUA_QL("<eof>")) == tp) {
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return 0; /* else... */
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static int pushline (lua_State *L, int firstline) {
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char buffer[LUA_MAXINPUT];
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const char *prmt = get_prompt(L, firstline);
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if (lua_readline(L, b, prmt) == 0)
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return 0; /* no input */
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if (l > 0 && b[l-1] == '\n') /* line ends with newline? */
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b[l-1] = '\0'; /* remove it */
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if (firstline && b[0] == '=') /* first line starts with `=' ? */
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lua_pushfstring(L, "return %s", b+1); /* change it to `return' */
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lua_pushstring(L, b);
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static int loadline (lua_State *L) {
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return -1; /* no input */
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for (;;) { /* repeat until gets a complete line */
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status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=stdin");
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if (!incomplete(L, status)) break; /* cannot try to add lines? */
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if (!pushline(L, 0)) /* no more input? */
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lua_pushliteral(L, "\n"); /* add a new line... */
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lua_insert(L, -2); /* ...between the two lines */
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lua_concat(L, 3); /* join them */
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lua_remove(L, 1); /* remove line */
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static void dotty (lua_State *L) {
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const char *oldprogname = progname;
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while ((status = loadline(L)) != -1) {
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if (status == 0) status = docall(L, 0, 0);
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if (status == 0 && lua_gettop(L) > 0) { /* any result to print? */
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lua_getglobal(L, "print");
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if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != 0)
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l_message(progname, lua_pushfstring(L,
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"error calling " LUA_QL("print") " (%s)",
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lua_tostring(L, -1)));
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lua_settop(L, 0); /* clear stack */
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progname = oldprogname;
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static int handle_script (lua_State *L, char **argv, int n) {
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int narg = getargs(L, argv, n); /* collect arguments */
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lua_setglobal(L, "arg");
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if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0)
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fname = NULL; /* stdin */
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status = luaL_loadfile(L, fname);
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lua_insert(L, -(narg+1));
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status = docall(L, narg, 0);
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return report(L, status);
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/* check that argument has no extra characters at the end */
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#define notail(x) {if ((x)[2] != '\0') return -1;}
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static int collectargs (char **argv, int *pi, int *pv, int *pe) {
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for (i = 1; argv[i] != NULL; i++) {
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if (argv[i][0] != '-') /* not an option? */
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switch (argv[i][1]) { /* option */
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return (argv[i+1] != NULL ? i+1 : 0);
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*pi = 1; /* go through */
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*pe = 1; /* go through */
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if (argv[i][2] == '\0') {
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if (argv[i] == NULL) return -1;
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default: return -1; /* invalid option */
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static int runargs (lua_State *L, char **argv, int n) {
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for (i = 1; i < n; i++) {
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if (argv[i] == NULL) continue;
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lua_assert(argv[i][0] == '-');
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switch (argv[i][1]) { /* option */
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const char *chunk = argv[i] + 2;
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if (*chunk == '\0') chunk = argv[++i];
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lua_assert(chunk != NULL);
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if (dostring(L, chunk, "=(command line)") != 0)
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const char *filename = argv[i] + 2;
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if (*filename == '\0') filename = argv[++i];
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lua_assert(filename != NULL);
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if (dolibrary(L, filename))
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return 1; /* stop if file fails */
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static int handle_luainit (lua_State *L) {
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const char *init = getenv(LUA_INIT);
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if (init == NULL) return 0; /* status OK */
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else if (init[0] == '@')
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return dofile(L, init+1);
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return dostring(L, init, "=" LUA_INIT);
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static int pmain (lua_State *L) {
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struct Smain *s = (struct Smain *)lua_touserdata(L, 1);
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char **argv = s->argv;
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int has_i = 0, has_v = 0, has_e = 0;
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if (argv[0] && argv[0][0]) progname = argv[0];
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lua_gc(L, LUA_GCSTOP, 0); /* stop collector during initialization */
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luaL_openlibs(L); /* open libraries */
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lua_gc(L, LUA_GCRESTART, 0);
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s->status = handle_luainit(L);
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if (s->status != 0) return 0;
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script = collectargs(argv, &has_i, &has_v, &has_e);
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if (script < 0) { /* invalid args? */
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if (has_v) print_version();
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s->status = runargs(L, argv, (script > 0) ? script : s->argc);
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if (s->status != 0) return 0;
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s->status = handle_script(L, argv, script);
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if (s->status != 0) return 0;
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else if (script == 0 && !has_e && !has_v) {
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if (lua_stdin_is_tty()) {
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else dofile(L, NULL); /* executes stdin as a file */
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int main (int argc, char **argv) {
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lua_State *L = lua_open(); /* create state */
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l_message(argv[0], "cannot create state: not enough memory");
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status = lua_cpcall(L, &pmain, &s);
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return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;