1 /* $NetBSD: lua.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $ */
4 ** Id: lua.c,v 1.225 2015/03/30 15:42:59 roberto Exp
5 ** Lua stand-alone interpreter
6 ** See Copyright Notice in lua.h
25 #if !defined(LUA_PROMPT)
26 #define LUA_PROMPT "> "
27 #define LUA_PROMPT2 ">> "
30 #if !defined(LUA_PROGNAME)
31 #define LUA_PROGNAME "lua"
34 #if !defined(LUA_MAXINPUT)
35 #define LUA_MAXINPUT 512
38 #if !defined(LUA_INIT_VAR)
39 #define LUA_INIT_VAR "LUA_INIT"
42 #define LUA_INITVARVERSION \
43 LUA_INIT_VAR "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR
47 ** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
48 ** is, whether we're running lua interactively).
50 #if !defined(lua_stdin_is_tty) /* { */
52 #if defined(LUA_USE_POSIX) /* { */
55 #define lua_stdin_is_tty() isatty(0)
57 #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'\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
) {
334 size_t len
; const char *line
;
335 lua_pushliteral(L
, "return ");
336 lua_pushvalue(L
, -2); /* duplicate line */
337 lua_concat(L
, 2); /* new line is "return ..." */
338 line
= lua_tolstring(L
, -1, &len
);
339 if ((status
= luaL_loadbuffer(L
, line
, len
, "=stdin")) == LUA_OK
) {
340 lua_remove(L
, -3); /* remove original line */
341 line
+= sizeof("return")/sizeof(char); /* remove 'return' for history */
342 if (line
[0] != '\0') /* non empty? */
343 lua_saveline(L
, line
); /* keep history */
346 lua_pop(L
, 2); /* remove result from 'luaL_loadbuffer' and new line */
352 ** Read multiple lines until a complete Lua statement
354 static int multiline (lua_State
*L
) {
355 for (;;) { /* repeat until gets a complete statement */
357 const char *line
= lua_tolstring(L
, 1, &len
); /* get what it has */
358 int status
= luaL_loadbuffer(L
, line
, len
, "=stdin"); /* try it */
359 if (!incomplete(L
, status
) || !pushline(L
, 0)) {
360 lua_saveline(L
, line
); /* keep history */
361 return status
; /* cannot or should not try to add continuation line */
363 lua_pushliteral(L
, "\n"); /* add newline... */
364 lua_insert(L
, -2); /* ...between the two lines */
365 lua_concat(L
, 3); /* join them */
371 ** Read a line and try to load (compile) it first as an expression (by
372 ** adding "return " in front of it) and second as a statement. Return
373 ** the final status of load/call with the resulting function (if any)
374 ** in the top of the stack.
376 static int loadline (lua_State
*L
) {
380 return -1; /* no input */
381 if ((status
= addreturn(L
)) != LUA_OK
) /* 'return ...' did not work? */
382 status
= multiline(L
); /* try as command, maybe with continuation lines */
383 lua_remove(L
, 1); /* remove line from the stack */
384 lua_assert(lua_gettop(L
) == 1);
390 ** Prints (calling the Lua 'print' function) any values on the stack
392 static void l_print (lua_State
*L
) {
393 int n
= lua_gettop(L
);
394 if (n
> 0) { /* any result to be printed? */
395 luaL_checkstack(L
, LUA_MINSTACK
, "too many results to print");
396 lua_getglobal(L
, "print");
398 if (lua_pcall(L
, n
, 0, 0) != LUA_OK
)
399 l_message(progname
, lua_pushfstring(L
, "error calling 'print' (%s)",
400 lua_tostring(L
, -1)));
406 ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
407 ** print any results.
409 static void doREPL (lua_State
*L
) {
411 const char *oldprogname
= progname
;
412 progname
= NULL
; /* no 'progname' on errors in interactive mode */
413 while ((status
= loadline(L
)) != -1) {
414 if (status
== LUA_OK
)
415 status
= docall(L
, 0, LUA_MULTRET
);
416 if (status
== LUA_OK
) l_print(L
);
417 else report(L
, status
);
419 lua_settop(L
, 0); /* clear stack */
421 progname
= oldprogname
;
426 ** Push on the stack the contents of table 'arg' from 1 to #arg
428 static int pushargs (lua_State
*L
) {
430 if (lua_getglobal(L
, "arg") != LUA_TTABLE
)
431 luaL_error(L
, "'arg' is not a table");
432 n
= (int)luaL_len(L
, -1);
433 luaL_checkstack(L
, n
+ 3, "too many arguments to script");
434 for (i
= 1; i
<= n
; i
++)
435 lua_rawgeti(L
, -i
, i
);
436 lua_remove(L
, -i
); /* remove table from the stack */
441 static int handle_script (lua_State
*L
, char **argv
) {
443 const char *fname
= argv
[0];
444 if (strcmp(fname
, "-") == 0 && strcmp(argv
[-1], "--") != 0)
445 fname
= NULL
; /* stdin */
446 status
= luaL_loadfile(L
, fname
);
447 if (status
== LUA_OK
) {
448 int n
= pushargs(L
); /* push arguments to script */
449 status
= docall(L
, n
, LUA_MULTRET
);
451 return report(L
, status
);
456 /* bits of various argument indicators in 'args' */
457 #define has_error 1 /* bad option */
458 #define has_i 2 /* -i */
459 #define has_v 4 /* -v */
460 #define has_e 8 /* -e */
461 #define has_E 16 /* -E */
464 ** Traverses all arguments from 'argv', returning a mask with those
465 ** needed before running any Lua code (or an error code if it finds
466 ** any invalid argument). 'first' returns the first not-handled argument
467 ** (either the script name or a bad argument in case of error).
469 static int collectargs (char **argv
, int *first
) {
472 for (i
= 1; argv
[i
] != NULL
; i
++) {
474 if (argv
[i
][0] != '-') /* not an option? */
475 return args
; /* stop handling options */
476 switch (argv
[i
][1]) { /* else check option */
478 if (argv
[i
][2] != '\0') /* extra characters after '--'? */
479 return has_error
; /* invalid option */
483 return args
; /* script "name" is '-' */
485 if (argv
[i
][2] != '\0') /* extra characters after 1st? */
486 return has_error
; /* invalid option */
490 args
|= has_i
; /* (-i implies -v) *//* FALLTHROUGH */
492 if (argv
[i
][2] != '\0') /* extra characters after 1st? */
493 return has_error
; /* invalid option */
497 args
|= has_e
; /* FALLTHROUGH */
498 case 'l': /* both options need an argument */
499 if (argv
[i
][2] == '\0') { /* no concatenated argument? */
500 i
++; /* try next 'argv' */
501 if (argv
[i
] == NULL
|| argv
[i
][0] == '-')
502 return has_error
; /* no next argument or it is another option */
505 default: /* invalid option */
509 *first
= i
; /* no script name */
515 ** Processes options 'e' and 'l', which involve running Lua code.
516 ** Returns 0 if some code raises an error.
518 static int runargs (lua_State
*L
, char **argv
, int n
) {
520 for (i
= 1; i
< n
; i
++) {
521 int option
= argv
[i
][1];
522 lua_assert(argv
[i
][0] == '-'); /* already checked */
523 if (option
== 'e' || option
== 'l') {
525 const char *extra
= argv
[i
] + 2; /* both options need an argument */
526 if (*extra
== '\0') extra
= argv
[++i
];
527 lua_assert(extra
!= NULL
);
528 status
= (option
== 'e')
529 ? dostring(L
, extra
, "=(command line)")
530 : dolibrary(L
, extra
);
531 if (status
!= LUA_OK
) return 0;
538 static int handle_luainit (lua_State
*L
) {
539 const char *name
= "=" LUA_INITVARVERSION
;
540 const char *init
= getenv(name
+ 1);
542 name
= "=" LUA_INIT_VAR
;
543 init
= getenv(name
+ 1); /* try alternative name */
545 if (init
== NULL
) return LUA_OK
;
546 else if (init
[0] == '@')
547 return dofile(L
, init
+1);
549 return dostring(L
, init
, name
);
554 ** Main body of stand-alone interpreter (to be called in protected mode).
555 ** Reads the options and handles them all.
557 static int pmain (lua_State
*L
) {
558 int argc
= (int)lua_tointeger(L
, 1);
559 char **argv
= (char **)lua_touserdata(L
, 2);
561 int args
= collectargs(argv
, &script
);
562 luaL_checkversion(L
); /* check that interpreter has correct version */
563 if (argv
[0] && argv
[0][0]) progname
= argv
[0];
564 if (args
== has_error
) { /* bad arg? */
565 print_usage(argv
[script
]); /* 'script' has index of bad arg. */
568 if (args
& has_v
) /* option '-v'? */
570 if (args
& has_E
) { /* option '-E'? */
571 lua_pushboolean(L
, 1); /* signal for libraries to ignore env. vars. */
572 lua_setfield(L
, LUA_REGISTRYINDEX
, "LUA_NOENV");
574 luaL_openlibs(L
); /* open standard libraries */
575 createargtable(L
, argv
, argc
, script
); /* create table 'arg' */
576 if (!(args
& has_E
)) { /* no option '-E'? */
577 if (handle_luainit(L
) != LUA_OK
) /* run LUA_INIT */
578 return 0; /* error running LUA_INIT */
580 if (!runargs(L
, argv
, script
)) /* execute arguments -e and -l */
581 return 0; /* something failed */
582 if (script
< argc
&& /* execute main script (if there is one) */
583 handle_script(L
, argv
+ script
) != LUA_OK
)
585 if (args
& has_i
) /* -i option? */
586 doREPL(L
); /* do read-eval-print loop */
587 else if (script
== argc
&& !(args
& (has_e
| has_v
))) { /* no arguments? */
588 if (lua_stdin_is_tty()) { /* running in interactive mode? */
590 doREPL(L
); /* do read-eval-print loop */
592 else dofile(L
, NULL
); /* executes stdin as a file */
594 lua_pushboolean(L
, 1); /* signal no errors */
599 int main (int argc
, char **argv
) {
601 lua_State
*L
= luaL_newstate(); /* create state */
603 l_message(argv
[0], "cannot create state: not enough memory");
606 lua_pushcfunction(L
, &pmain
); /* to call 'pmain' in protected mode */
607 lua_pushinteger(L
, argc
); /* 1st argument */
608 lua_pushlightuserdata(L
, argv
); /* 2nd argument */
609 status
= lua_pcall(L
, 2, 1, 0); /* do the call */
610 result
= lua_toboolean(L
, -1); /* get result */
613 return (result
&& status
== LUA_OK
) ? EXIT_SUCCESS
: EXIT_FAILURE
;