2 ** $Id: lua.c,v 1.230.1.1 2017/04/19 17:29:57 roberto Exp $
3 ** Lua stand-alone interpreter
4 ** See Copyright Notice in lua.h
24 #if !defined(LUA_PROMPT)
25 #define LUA_PROMPT "> "
26 #define LUA_PROMPT2 ">> "
29 #if !defined(LUA_PROGNAME)
30 #define LUA_PROGNAME "lua"
33 #if !defined(LUA_MAXINPUT)
34 #define LUA_MAXINPUT 512
37 #if !defined(LUA_INIT_VAR)
38 #define LUA_INIT_VAR "LUA_INIT"
41 #define LUA_INITVARVERSION LUA_INIT_VAR LUA_VERSUFFIX
45 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
46 ** is, whether we're running lua interactively).
48 #if !defined(lua_stdin_is_tty) /* { */
50 #if defined(LUA_USE_POSIX) /* { */
53 #define lua_stdin_is_tty() isatty(0)
55 #elif defined(LUA_USE_WINDOWS) /* }{ */
60 #define lua_stdin_is_tty() _isatty(_fileno(stdin))
64 /* ISO C definition */
65 #define lua_stdin_is_tty() 1 /* assume stdin is a tty */
73 ** lua_readline defines how to show a prompt and then read a line from
74 ** the standard input.
75 ** lua_saveline defines how to "save" a read line in a "history".
76 ** lua_freeline defines how to free a line read by lua_readline.
78 #if !defined(lua_readline) /* { */
80 #if defined(LUA_USE_READLINE) /* { */
82 #include <readline/readline.h>
83 #include <readline/history.h>
84 #define lua_readline(L,b,p) ((void)L, ((b)=readline(p)) != NULL)
85 #define lua_saveline(L,line) ((void)L, add_history(line))
86 #define lua_freeline(L,b) ((void)L, free(b))
90 #define lua_readline(L,b,p) \
91 ((void)L, fputs(p, stdout), fflush(stdout), /* show prompt */ \
92 fgets(b, LUA_MAXINPUT, stdin) != NULL) /* get line */
93 #define lua_saveline(L,line) { (void)L; (void)line; }
94 #define lua_freeline(L,b) { (void)L; (void)b; }
103 static lua_State *globalL = NULL;
105 static const char *progname = LUA_PROGNAME;
109 ** Hook set by signal function to stop the interpreter.
111 static void lstop (lua_State *L, lua_Debug *ar) {
112 (void)ar; /* unused arg. */
113 lua_sethook(L, NULL, 0, 0); /* reset hook */
114 luaL_error(L, "interrupted!");
119 ** Function to be called at a C signal. Because a C signal cannot
120 ** just change a Lua state (as there is no proper synchronization),
121 ** this function only sets a hook that, when called, will stop the
124 static void laction (int i) {
125 signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */
126 lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
130 static void print_usage (const char *badoption) {
131 lua_writestringerror("%s: ", progname);
132 if (badoption[1] == 'e' || badoption[1] == 'l')
133 lua_writestringerror("'%s' needs argument\n", badoption);
135 lua_writestringerror("unrecognized option '%s'\n", badoption);
136 lua_writestringerror(
137 "usage: %s [options] [script [args]]\n"
138 "Available options are:\n"
139 " -e stat execute string 'stat'\n"
140 " -i enter interactive mode after executing 'script'\n"
141 " -l name require library 'name' into global 'name'\n"
142 " -v show version information\n"
143 " -E ignore environment variables\n"
144 " -- stop handling options\n"
145 " - stop handling options and execute stdin\n"
152 ** Prints an error message, adding the program name in front of it
155 static void l_message (const char *pname, const char *msg) {
156 if (pname) lua_writestringerror("%s: ", pname);
157 lua_writestringerror("%s\n", msg);
162 ** Check whether 'status' is not OK and, if so, prints the error
163 ** message on the top of the stack. It assumes that the error object
164 ** is a string, as it was either generated by Lua or by 'msghandler'.
166 static int report (lua_State *L, int status) {
167 if (status != LUA_OK) {
168 const char *msg = lua_tostring(L, -1);
169 l_message(progname, msg);
170 lua_pop(L, 1); /* remove message */
177 ** Message handler used to run all chunks
179 static int msghandler (lua_State *L) {
180 const char *msg = lua_tostring(L, 1);
181 if (msg == NULL) { /* is error object not a string? */
182 if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */
183 lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */
184 return 1; /* that is the message */
186 msg = lua_pushfstring(L, "(error object is a %s value)",
187 luaL_typename(L, 1));
189 luaL_traceback(L, L, msg, 1); /* append a standard traceback */
190 return 1; /* return the traceback */
195 ** Interface to 'lua_pcall', which sets appropriate message function
196 ** and C-signal handler. Used to run all chunks.
198 static int docall (lua_State *L, int narg, int nres) {
200 int base = lua_gettop(L) - narg; /* function index */
201 lua_pushcfunction(L, msghandler); /* push message handler */
202 lua_insert(L, base); /* put it under function and args */
203 globalL = L; /* to be available to 'laction' */
204 signal(SIGINT, laction); /* set C-signal handler */
205 status = lua_pcall(L, narg, nres, base);
206 signal(SIGINT, SIG_DFL); /* reset C-signal handler */
207 lua_remove(L, base); /* remove message handler from the stack */
212 static void print_version (void) {
213 lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
219 ** Create the 'arg' table, which stores all arguments from the
220 ** command line ('argv'). It should be aligned so that, at index 0,
221 ** it has 'argv[script]', which is the script name. The arguments
222 ** to the script (everything after 'script') go to positive indices;
223 ** other arguments (before the script name) go to negative indices.
224 ** If there is no script name, assume interpreter's name as base.
226 static void createargtable (lua_State *L, char **argv, int argc, int script) {
228 if (script == argc) script = 0; /* no script name? */
229 narg = argc - (script + 1); /* number of positive indices */
230 lua_createtable(L, narg, script + 1);
231 for (i = 0; i < argc; i++) {
232 lua_pushstring(L, argv[i]);
233 lua_rawseti(L, -2, i - script);
235 lua_setglobal(L, "arg");
239 static int dochunk (lua_State *L, int status) {
240 if (status == LUA_OK) status = docall(L, 0, 0);
241 return report(L, status);
245 static int dofile (lua_State *L, const char *name) {
246 return dochunk(L, luaL_loadfile(L, name));
250 static int dostring (lua_State *L, const char *s, const char *name) {
251 return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name));
256 ** Calls 'require(name)' and stores the result in a global variable
257 ** with the given name.
259 static int dolibrary (lua_State *L, const char *name) {
261 lua_getglobal(L, "require");
262 lua_pushstring(L, name);
263 status = docall(L, 1, 1); /* call 'require(name)' */
264 if (status == LUA_OK)
265 lua_setglobal(L, name); /* global[name] = require return */
266 return report(L, status);
271 ** Returns the string to be used as a prompt by the interpreter.
273 static const char *get_prompt (lua_State *L, int firstline) {
275 lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
276 p = lua_tostring(L, -1);
277 if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
281 /* mark in error messages for incomplete statements */
282 #define EOFMARK "<eof>"
283 #define marklen (sizeof(EOFMARK)/sizeof(char) - 1)
287 ** Check whether 'status' signals a syntax error and the error
288 ** message at the top of the stack ends with the above mark for
289 ** incomplete statements.
291 static int incomplete (lua_State *L, int status) {
292 if (status == LUA_ERRSYNTAX) {
294 const char *msg = lua_tolstring(L, -1, &lmsg);
295 if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0) {
300 return 0; /* else... */
305 ** Prompt the user, read a line, and push it into the Lua stack.
307 static int pushline (lua_State *L, int firstline) {
308 char buffer[LUA_MAXINPUT];
311 const char *prmt = get_prompt(L, firstline);
312 int readstatus = lua_readline(L, b, prmt);
314 return 0; /* no input (prompt will be popped by caller) */
315 lua_pop(L, 1); /* remove prompt */
317 if (l > 0 && b[l-1] == '\n') /* line ends with newline? */
318 b[--l] = '\0'; /* remove it */
319 if (firstline && b[0] == '=') /* for compatibility with 5.2, ... */
320 lua_pushfstring(L, "return %s", b + 1); /* change '=' to 'return' */
322 lua_pushlstring(L, b, l);
329 ** Try to compile line on the stack as 'return <line>;'; on return, stack
330 ** has either compiled chunk or original line (if compilation failed).
332 static int addreturn (lua_State *L) {
333 const char *line = lua_tostring(L, -1); /* original line */
334 const char *retline = lua_pushfstring(L, "return %s;", line);
335 int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin");
336 if (status == LUA_OK) {
337 lua_remove(L, -2); /* remove modified line */
338 if (line[0] != '\0') /* non empty? */
339 lua_saveline(L, line); /* keep history */
342 lua_pop(L, 2); /* pop result from 'luaL_loadbuffer' and modified line */
348 ** Read multiple lines until a complete Lua statement
350 static int multiline (lua_State *L) {
351 for (;;) { /* repeat until gets a complete statement */
353 const char *line = lua_tolstring(L, 1, &len); /* get what it has */
354 int status = luaL_loadbuffer(L, line, len, "=stdin"); /* try it */
355 if (!incomplete(L, status) || !pushline(L, 0)) {
356 lua_saveline(L, line); /* keep history */
357 return status; /* cannot or should not try to add continuation line */
359 lua_pushliteral(L, "\n"); /* add newline... */
360 lua_insert(L, -2); /* ...between the two lines */
361 lua_concat(L, 3); /* join them */
367 ** Read a line and try to load (compile) it first as an expression (by
368 ** adding "return " in front of it) and second as a statement. Return
369 ** the final status of load/call with the resulting function (if any)
370 ** in the top of the stack.
372 static int loadline (lua_State *L) {
376 return -1; /* no input */
377 if ((status = addreturn(L)) != LUA_OK) /* 'return ...' did not work? */
378 status = multiline(L); /* try as command, maybe with continuation lines */
379 lua_remove(L, 1); /* remove line from the stack */
380 lua_assert(lua_gettop(L) == 1);
386 ** Prints (calling the Lua 'print' function) any values on the stack
388 static void l_print (lua_State *L) {
389 int n = lua_gettop(L);
390 if (n > 0) { /* any result to be printed? */
391 luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
392 lua_getglobal(L, "print");
394 if (lua_pcall(L, n, 0, 0) != LUA_OK)
395 l_message(progname, lua_pushfstring(L, "error calling 'print' (%s)",
396 lua_tostring(L, -1)));
402 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
403 ** print any results.
405 static void doREPL (lua_State *L) {
407 const char *oldprogname = progname;
408 progname = NULL; /* no 'progname' on errors in interactive mode */
409 while ((status = loadline(L)) != -1) {
410 if (status == LUA_OK)
411 status = docall(L, 0, LUA_MULTRET);
412 if (status == LUA_OK) l_print(L);
413 else report(L, status);
415 lua_settop(L, 0); /* clear stack */
417 progname = oldprogname;
422 ** Push on the stack the contents of table 'arg' from 1 to #arg
424 static int pushargs (lua_State *L) {
426 if (lua_getglobal(L, "arg") != LUA_TTABLE)
427 luaL_error(L, "'arg' is not a table");
428 n = (int)luaL_len(L, -1);
429 luaL_checkstack(L, n + 3, "too many arguments to script");
430 for (i = 1; i <= n; i++)
431 lua_rawgeti(L, -i, i);
432 lua_remove(L, -i); /* remove table from the stack */
437 static int handle_script (lua_State *L, char **argv) {
439 const char *fname = argv[0];
440 if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
441 fname = NULL; /* stdin */
442 status = luaL_loadfile(L, fname);
443 if (status == LUA_OK) {
444 int n = pushargs(L); /* push arguments to script */
445 status = docall(L, n, LUA_MULTRET);
447 return report(L, status);
452 /* bits of various argument indicators in 'args' */
453 #define has_error 1 /* bad option */
454 #define has_i 2 /* -i */
455 #define has_v 4 /* -v */
456 #define has_e 8 /* -e */
457 #define has_E 16 /* -E */
460 ** Traverses all arguments from 'argv', returning a mask with those
461 ** needed before running any Lua code (or an error code if it finds
462 ** any invalid argument). 'first' returns the first not-handled argument
463 ** (either the script name or a bad argument in case of error).
465 static int collectargs (char **argv, int *first) {
468 for (i = 1; argv[i] != NULL; i++) {
470 if (argv[i][0] != '-') /* not an option? */
471 return args; /* stop handling options */
472 switch (argv[i][1]) { /* else check option */
474 if (argv[i][2] != '\0') /* extra characters after '--'? */
475 return has_error; /* invalid option */
479 return args; /* script "name" is '-' */
481 if (argv[i][2] != '\0') /* extra characters after 1st? */
482 return has_error; /* invalid option */
486 args |= has_i; /* (-i implies -v) *//* FALLTHROUGH */
488 if (argv[i][2] != '\0') /* extra characters after 1st? */
489 return has_error; /* invalid option */
493 args |= has_e; /* FALLTHROUGH */
494 case 'l': /* both options need an argument */
495 if (argv[i][2] == '\0') { /* no concatenated argument? */
496 i++; /* try next 'argv' */
497 if (argv[i] == NULL || argv[i][0] == '-')
498 return has_error; /* no next argument or it is another option */
501 default: /* invalid option */
505 *first = i; /* no script name */
511 ** Processes options 'e' and 'l', which involve running Lua code.
512 ** Returns 0 if some code raises an error.
514 static int runargs (lua_State *L, char **argv, int n) {
516 for (i = 1; i < n; i++) {
517 int option = argv[i][1];
518 lua_assert(argv[i][0] == '-'); /* already checked */
519 if (option == 'e' || option == 'l') {
521 const char *extra = argv[i] + 2; /* both options need an argument */
522 if (*extra == '\0') extra = argv[++i];
523 lua_assert(extra != NULL);
524 status = (option == 'e')
525 ? dostring(L, extra, "=(command line)")
526 : dolibrary(L, extra);
527 if (status != LUA_OK) return 0;
535 static int handle_luainit (lua_State *L) {
536 const char *name = "=" LUA_INITVARVERSION;
537 const char *init = getenv(name + 1);
539 name = "=" LUA_INIT_VAR;
540 init = getenv(name + 1); /* try alternative name */
542 if (init == NULL) return LUA_OK;
543 else if (init[0] == '@')
544 return dofile(L, init+1);
546 return dostring(L, init, name);
551 ** Main body of stand-alone interpreter (to be called in protected mode).
552 ** Reads the options and handles them all.
554 static int pmain (lua_State *L) {
555 int argc = (int)lua_tointeger(L, 1);
556 char **argv = (char **)lua_touserdata(L, 2);
558 int args = collectargs(argv, &script);
559 luaL_checkversion(L); /* check that interpreter has correct version */
560 if (argv[0] && argv[0][0]) progname = argv[0];
561 if (args == has_error) { /* bad arg? */
562 print_usage(argv[script]); /* 'script' has index of bad arg. */
565 if (args & has_v) /* option '-v'? */
567 if (args & has_E) { /* option '-E'? */
568 lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */
569 lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
571 luaL_openlibs(L); /* open standard libraries */
572 createargtable(L, argv, argc, script); /* create table 'arg' */
573 if (!(args & has_E)) { /* no option '-E'? */
574 if (handle_luainit(L) != LUA_OK) /* run LUA_INIT */
575 return 0; /* error running LUA_INIT */
577 if (!runargs(L, argv, script)) /* execute arguments -e and -l */
578 return 0; /* something failed */
579 if (script < argc && /* execute main script (if there is one) */
580 handle_script(L, argv + script) != LUA_OK)
582 if (args & has_i) /* -i option? */
583 doREPL(L); /* do read-eval-print loop */
584 else if (script == argc && !(args & (has_e | has_v))) { /* no arguments? */
585 if (lua_stdin_is_tty()) { /* running in interactive mode? */
587 doREPL(L); /* do read-eval-print loop */
589 else dofile(L, NULL); /* executes stdin as a file */
591 lua_pushboolean(L, 1); /* signal no errors */
596 int main (int argc, char **argv) {
598 lua_State *L = luaL_newstate(); /* create state */
600 l_message(argv[0], "cannot create state: not enough memory");
603 lua_pushcfunction(L, &pmain); /* to call 'pmain' in protected mode */
604 lua_pushinteger(L, argc); /* 1st argument */
605 lua_pushlightuserdata(L, argv); /* 2nd argument */
606 status = lua_pcall(L, 2, 1, 0); /* do the call */
607 result = lua_toboolean(L, -1); /* get result */
610 return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;