Lua 5.1.4: lua.c


The default standalone Lua interpreter
L0001 /* L0002 ** $Id: lua.c,v 1.160.1.2 2007/12/28 15:32:23 roberto Exp $ L0003 ** Lua stand-alone interpreter L0004 ** See Copyright Notice in lua.h L0005 */ L0006 L0007 L0008 #include <signal.h> L0009 #include <stdio.h> L0010 #include <stdlib.h> L0011 #include <string.h> L0012 L0013 #define lua_c L0014 L0015 #include "lua.h" L0016 L0017 #include "lauxlib.h" L0018 #include "lualib.h" L0019 L0020 L0021 L0022 static lua_State *globalL = NULL; L0023 L0024 static const char *progname = LUA_PROGNAME; L0025 L0026 L0027 L0028 static void lstop (lua_State *L, lua_Debug *ar) { L0029 (void)ar; /* unused arg. */ L0030 lua_sethook(L, NULL, 0, 0); L0031 luaL_error(L, "interrupted!"); L0032 } L0033 L0034 L0035 static void laction (int i) { L0036 signal(i, SIG_DFL); /* if another SIGINT happens before lstop, L0037 terminate process (default action) */ L0038 lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1); L0039 } L0040 L0041 L0042 static void print_usage (void) { L0043 fprintf(stderr, L0044 "usage: %s [options] [script [args]].\n" L0045 "Available options are:\n" L0046 " -e stat execute string " LUA_QL("stat") "\n" L0047 " -l name require library " LUA_QL("name") "\n" L0048 " -i enter interactive mode after executing " LUA_QL("script") "\n" L0049 " -v show version information\n" L0050 " -- stop handling options\n" L0051 " - execute stdin and stop handling options\n" L0052 , L0053 progname); L0054 fflush(stderr); L0055 } L0056 L0057 L0058 static void l_message (const char *pname, const char *msg) { L0059 if (pname) fprintf(stderr, "%s: ", pname); L0060 fprintf(stderr, "%s\n", msg); L0061 fflush(stderr); L0062 } L0063 L0064 L0065 static int report (lua_State *L, int status) { L0066 if (status && !lua_isnil(L, -1)) { L0067 const char *msg = lua_tostring(L, -1); L0068 if (msg == NULL) msg = "(error object is not a string)"; L0069 l_message(progname, msg); L0070 lua_pop(L, 1); L0071 } L0072 return status; L0073 } L0074 L0075 L0076 static int traceback (lua_State *L) { L0077 if (!lua_isstring(L, 1)) /* 'message' not a string? */ L0078 return 1; /* keep it intact */ L0079 lua_getfield(L, LUA_GLOBALSINDEX, "debug"); L0080 if (!lua_istable(L, -1)) { L0081 lua_pop(L, 1); L0082 return 1; L0083 } L0084 lua_getfield(L, -1, "traceback"); L0085 if (!lua_isfunction(L, -1)) { L0086 lua_pop(L, 2); L0087 return 1; L0088 } L0089 lua_pushvalue(L, 1); /* pass error message */ L0090 lua_pushinteger(L, 2); /* skip this function and traceback */ L0091 lua_call(L, 2, 1); /* call debug.traceback */ L0092 return 1; L0093 } L0094 L0095 L0096 static int docall (lua_State *L, int narg, int clear) { L0097 int status; L0098 int base = lua_gettop(L) - narg; /* function index */ L0099 lua_pushcfunction(L, traceback); /* push traceback function */ L0100 lua_insert(L, base); /* put it under chunk and args */ L0101 signal(SIGINT, laction); L0102 status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base); L0103 signal(SIGINT, SIG_DFL); L0104 lua_remove(L, base); /* remove traceback function */ L0105 /* force a complete garbage collection in case of errors */ L0106 if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0); L0107 return status; L0108 } L0109 L0110 L0111 static void print_version (void) { L0112 l_message(NULL, LUA_RELEASE " " LUA_COPYRIGHT); L0113 } L0114 L0115 L0116 static int getargs (lua_State *L, char **argv, int n) { L0117 int narg; L0118 int i; L0119 int argc = 0; L0120 while (argv[argc]) argc++; /* count total number of arguments */ L0121 narg = argc - (n + 1); /* number of arguments to the script */ L0122 luaL_checkstack(L, narg + 3, "too many arguments to script"); L0123 for (i=n+1; i < argc; i++) L0124 lua_pushstring(L, argv[i]); L0125 lua_createtable(L, narg, n + 1); L0126 for (i=0; i < argc; i++) { L0127 lua_pushstring(L, argv[i]); L0128 lua_rawseti(L, -2, i - n); L0129 } L0130 return narg; L0131 } L0132 L0133 L0134 static int dofile (lua_State *L, const char *name) { L0135 int status = luaL_loadfile(L, name) || docall(L, 0, 1); L0136 return report(L, status); L0137 } L0138 L0139 L0140 static int dostring (lua_State *L, const char *s, const char *name) { L0141 int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1); L0142 return report(L, status); L0143 } L0144 L0145 L0146 static int dolibrary (lua_State *L, const char *name) { L0147 lua_getglobal(L, "require"); L0148 lua_pushstring(L, name); L0149 return report(L, docall(L, 1, 1)); L0150 } L0151 L0152 L0153 static const char *get_prompt (lua_State *L, int firstline) { L0154 const char *p; L0155 lua_getfield(L, LUA_GLOBALSINDEX, firstline ? "_PROMPT" : "_PROMPT2"); L0156 p = lua_tostring(L, -1); L0157 if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2); L0158 lua_pop(L, 1); /* remove global */ L0159 return p; L0160 } L0161 L0162 L0163 static int incomplete (lua_State *L, int status) { L0164 if (status == LUA_ERRSYNTAX) { L0165 size_t lmsg; L0166 const char *msg = lua_tolstring(L, -1, &lmsg); L0167 const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1); L0168 if (strstr(msg, LUA_QL("<eof>")) == tp) { L0169 lua_pop(L, 1); L0170 return 1; L0171 } L0172 } L0173 return 0; /* else... */ L0174 } L0175 L0176 L0177 static int pushline (lua_State *L, int firstline) { L0178 char buffer[LUA_MAXINPUT]; L0179 char *b = buffer; L0180 size_t l; L0181 const char *prmt = get_prompt(L, firstline); L0182 if (lua_readline(L, b, prmt) == 0) L0183 return 0; /* no input */ L0184 l = strlen(b); L0185 if (l > 0 && b[l-1] == '\n') /* line ends with newline? */ L0186 b[l-1] = '\0'; /* remove it */ L0187 if (firstline && b[0] == '=') /* first line starts with `=' ? */ L0188 lua_pushfstring(L, "return %s", b+1); /* change it to `return' */ L0189 else L0190 lua_pushstring(L, b); L0191 lua_freeline(L, b); L0192 return 1; L0193 } L0194 L0195 L0196 static int loadline (lua_State *L) { L0197 int status; L0198 lua_settop(L, 0); L0199 if (!pushline(L, 1)) L0200 return -1; /* no input */ L0201 for (;;) { /* repeat until gets a complete line */ L0202 status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=stdin"); L0203 if (!incomplete(L, status)) break; /* cannot try to add lines? */ L0204 if (!pushline(L, 0)) /* no more input? */ L0205 return -1; L0206 lua_pushliteral(L, "\n"); /* add a new line... */ L0207 lua_insert(L, -2); /* ...between the two lines */ L0208 lua_concat(L, 3); /* join them */ L0209 } L0210 lua_saveline(L, 1); L0211 lua_remove(L, 1); /* remove line */ L0212 return status; L0213 } L0214 L0215 L0216 static void dotty (lua_State *L) { L0217 int status; L0218 const char *oldprogname = progname; L0219 progname = NULL; L0220 while ((status = loadline(L)) != -1) { L0221 if (status == 0) status = docall(L, 0, 0); L0222 report(L, status); L0223 if (status == 0 && lua_gettop(L) > 0) { /* any result to print? */ L0224 lua_getglobal(L, "print"); L0225 lua_insert(L, 1); L0226 if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != 0) L0227 l_message(progname, lua_pushfstring(L, L0228 "error calling " LUA_QL("print") " (%s)", L0229 lua_tostring(L, -1))); L0230 } L0231 } L0232 lua_settop(L, 0); /* clear stack */ L0233 fputs("\n", stdout); L0234 fflush(stdout); L0235 progname = oldprogname; L0236 } L0237 L0238 L0239 static int handle_script (lua_State *L, char **argv, int n) { L0240 int status; L0241 const char *fname; L0242 int narg = getargs(L, argv, n); /* collect arguments */ L0243 lua_setglobal(L, "arg"); L0244 fname = argv[n]; L0245 if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0) L0246 fname = NULL; /* stdin */ L0247 status = luaL_loadfile(L, fname); L0248 lua_insert(L, -(narg+1)); L0249 if (status == 0) L0250 status = docall(L, narg, 0); L0251 else L0252 lua_pop(L, narg); L0253 return report(L, status); L0254 } L0255 L0256 L0257 /* check that argument has no extra characters at the end */ L0258 #define notail(x) {if ((x)[2] != '\0') return -1;} L0259 L0260 L0261 static int collectargs (char **argv, int *pi, int *pv, int *pe) { L0262 int i; L0263 for (i = 1; argv[i] != NULL; i++) { L0264 if (argv[i][0] != '-') /* not an option? */ L0265 return i; L0266 switch (argv[i][1]) { /* option */ L0267 case '-': L0268 notail(argv[i]); L0269 return (argv[i+1] != NULL ? i+1 : 0); L0270 case '\0': L0271 return i; L0272 case 'i': L0273 notail(argv[i]); L0274 *pi = 1; /* go through */ L0275 case 'v': L0276 notail(argv[i]); L0277 *pv = 1; L0278 break; L0279 case 'e': L0280 *pe = 1; /* go through */ L0281 case 'l': L0282 if (argv[i][2] == '\0') { L0283 i++; L0284 if (argv[i] == NULL) return -1; L0285 } L0286 break; L0287 default: return -1; /* invalid option */ L0288 } L0289 } L0290 return 0; L0291 } L0292 L0293 L0294 static int runargs (lua_State *L, char **argv, int n) { L0295 int i; L0296 for (i = 1; i < n; i++) { L0297 if (argv[i] == NULL) continue; L0298 lua_assert(argv[i][0] == '-'); L0299 switch (argv[i][1]) { /* option */ L0300 case 'e': { L0301 const char *chunk = argv[i] + 2; L0302 if (*chunk == '\0') chunk = argv[++i]; L0303 lua_assert(chunk != NULL); L0304 if (dostring(L, chunk, "=(command line)") != 0) L0305 return 1; L0306 break; L0307 } L0308 case 'l': { L0309 const char *filename = argv[i] + 2; L0310 if (*filename == '\0') filename = argv[++i]; L0311 lua_assert(filename != NULL); L0312 if (dolibrary(L, filename)) L0313 return 1; /* stop if file fails */ L0314 break; L0315 } L0316 default: break; L0317 } L0318 } L0319 return 0; L0320 } L0321 L0322 L0323 static int handle_luainit (lua_State *L) { L0324 const char *init = getenv(LUA_INIT); L0325 if (init == NULL) return 0; /* status OK */ L0326 else if (init[0] == '@') L0327 return dofile(L, init+1); L0328 else L0329 return dostring(L, init, "=" LUA_INIT); L0330 } L0331 L0332 L0333 struct Smain { L0334 int argc; L0335 char **argv; L0336 int status; L0337 }; L0338 L0339 L0340 static int pmain (lua_State *L) { L0341 struct Smain *s = (struct Smain *)lua_touserdata(L, 1); L0342 char **argv = s->argv; L0343 int script; L0344 int has_i = 0, has_v = 0, has_e = 0; L0345 globalL = L; L0346 if (argv[0] && argv[0][0]) progname = argv[0]; L0347 lua_gc(L, LUA_GCSTOP, 0); /* stop collector during initialization */ L0348 luaL_openlibs(L); /* open libraries */ L0349 lua_gc(L, LUA_GCRESTART, 0); L0350 s->status = handle_luainit(L); L0351 if (s->status != 0) return 0; L0352 script = collectargs(argv, &has_i, &has_v, &has_e); L0353 if (script < 0) { /* invalid args? */ L0354 print_usage(); L0355 s->status = 1; L0356 return 0; L0357 } L0358 if (has_v) print_version(); L0359 s->status = runargs(L, argv, (script > 0) ? script : s->argc); L0360 if (s->status != 0) return 0; L0361 if (script) L0362 s->status = handle_script(L, argv, script); L0363 if (s->status != 0) return 0; L0364 if (has_i) L0365 dotty(L); L0366 else if (script == 0 && !has_e && !has_v) { L0367 if (lua_stdin_is_tty()) { L0368 print_version(); L0369 dotty(L); L0370 } L0371 else dofile(L, NULL); /* executes stdin as a file */ L0372 } L0373 return 0; L0374 } L0375 L0376 L0377 int main (int argc, char **argv) { L0378 int status; L0379 struct Smain s; L0380 lua_State *L = lua_open(); /* create state */ L0381 if (L == NULL) { L0382 l_message(argv[0], "cannot create state: not enough memory"); L0383 return EXIT_FAILURE; L0384 } L0385 s.argc = argc; L0386 s.argv = argv; L0387 status = lua_cpcall(L, &pmain, &s); L0388 report(L, status); L0389 lua_close(L); L0390 return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS; L0391 } L0392

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