llex.c (16163B)
1 /* 2 ** $Id: llex.c,v 2.96.1.1 2017/04/19 17:20:42 roberto Exp $ 3 ** Lexical Analyzer 4 ** See Copyright Notice in lua.h 5 */ 6 7 #define llex_c 8 #define LUA_CORE 9 10 #include "lprefix.h" 11 12 13 #include <locale.h> 14 #include <string.h> 15 16 #include "lua.h" 17 18 #include "lctype.h" 19 #include "ldebug.h" 20 #include "ldo.h" 21 #include "lgc.h" 22 #include "llex.h" 23 #include "lobject.h" 24 #include "lparser.h" 25 #include "lstate.h" 26 #include "lstring.h" 27 #include "ltable.h" 28 #include "lzio.h" 29 30 31 32 #define next(ls) (ls->current = zgetc(ls->z)) 33 34 35 36 #define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r') 37 38 39 /* ORDER RESERVED */ 40 static const char *const luaX_tokens [] = { 41 "and", "break", "do", "else", "elseif", 42 "end", "false", "for", "function", "goto", "if", 43 "in", "local", "nil", "not", "or", "repeat", 44 "return", "then", "true", "until", "while", 45 "//", "..", "...", "==", ">=", "<=", "~=", 46 "<<", ">>", "::", "<eof>", 47 "<number>", "<integer>", "<name>", "<string>" 48 }; 49 50 51 #define save_and_next(ls) (save(ls, ls->current), next(ls)) 52 53 54 static l_noret lexerror (LexState *ls, const char *msg, int token); 55 56 57 static void save (LexState *ls, int c) { 58 Mbuffer *b = ls->buff; 59 if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) { 60 size_t newsize; 61 if (luaZ_sizebuffer(b) >= MAX_SIZE/2) 62 lexerror(ls, "lexical element too long", 0); 63 newsize = luaZ_sizebuffer(b) * 2; 64 luaZ_resizebuffer(ls->L, b, newsize); 65 } 66 b->buffer[luaZ_bufflen(b)++] = cast(char, c); 67 } 68 69 70 void luaX_init (lua_State *L) { 71 int i; 72 TString *e = luaS_newliteral(L, LUA_ENV); /* create env name */ 73 luaC_fix(L, obj2gco(e)); /* never collect this name */ 74 for (i=0; i<NUM_RESERVED; i++) { 75 TString *ts = luaS_new(L, luaX_tokens[i]); 76 luaC_fix(L, obj2gco(ts)); /* reserved words are never collected */ 77 ts->extra = cast_byte(i+1); /* reserved word */ 78 } 79 } 80 81 82 const char *luaX_token2str (LexState *ls, int token) { 83 if (token < FIRST_RESERVED) { /* single-byte symbols? */ 84 lua_assert(token == cast_uchar(token)); 85 return luaO_pushfstring(ls->L, "'%c'", token); 86 } 87 else { 88 const char *s = luaX_tokens[token - FIRST_RESERVED]; 89 if (token < TK_EOS) /* fixed format (symbols and reserved words)? */ 90 return luaO_pushfstring(ls->L, "'%s'", s); 91 else /* names, strings, and numerals */ 92 return s; 93 } 94 } 95 96 97 static const char *txtToken (LexState *ls, int token) { 98 switch (token) { 99 case TK_NAME: case TK_STRING: 100 case TK_FLT: case TK_INT: 101 save(ls, '\0'); 102 return luaO_pushfstring(ls->L, "'%s'", luaZ_buffer(ls->buff)); 103 default: 104 return luaX_token2str(ls, token); 105 } 106 } 107 108 109 static l_noret lexerror (LexState *ls, const char *msg, int token) { 110 msg = luaG_addinfo(ls->L, msg, ls->source, ls->linenumber); 111 if (token) 112 luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token)); 113 luaD_throw(ls->L, LUA_ERRSYNTAX); 114 } 115 116 117 l_noret luaX_syntaxerror (LexState *ls, const char *msg) { 118 lexerror(ls, msg, ls->t.token); 119 } 120 121 122 /* 123 ** creates a new string and anchors it in scanner's table so that 124 ** it will not be collected until the end of the compilation 125 ** (by that time it should be anchored somewhere) 126 */ 127 TString *luaX_newstring (LexState *ls, const char *str, size_t l) { 128 lua_State *L = ls->L; 129 TValue *o; /* entry for 'str' */ 130 TString *ts = luaS_newlstr(L, str, l); /* create new string */ 131 setsvalue2s(L, L->top++, ts); /* temporarily anchor it in stack */ 132 o = luaH_set(L, ls->h, L->top - 1); 133 if (ttisnil(o)) { /* not in use yet? */ 134 /* boolean value does not need GC barrier; 135 table has no metatable, so it does not need to invalidate cache */ 136 setbvalue(o, 1); /* t[string] = true */ 137 luaC_checkGC(L); 138 } 139 else { /* string already present */ 140 ts = tsvalue(keyfromval(o)); /* re-use value previously stored */ 141 } 142 L->top--; /* remove string from stack */ 143 return ts; 144 } 145 146 147 /* 148 ** increment line number and skips newline sequence (any of 149 ** \n, \r, \n\r, or \r\n) 150 */ 151 static void inclinenumber (LexState *ls) { 152 int old = ls->current; 153 lua_assert(currIsNewline(ls)); 154 next(ls); /* skip '\n' or '\r' */ 155 if (currIsNewline(ls) && ls->current != old) 156 next(ls); /* skip '\n\r' or '\r\n' */ 157 if (++ls->linenumber >= MAX_INT) 158 lexerror(ls, "chunk has too many lines", 0); 159 } 160 161 162 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source, 163 int firstchar) { 164 ls->t.token = 0; 165 ls->L = L; 166 ls->current = firstchar; 167 ls->lookahead.token = TK_EOS; /* no look-ahead token */ 168 ls->z = z; 169 ls->fs = NULL; 170 ls->linenumber = 1; 171 ls->lastline = 1; 172 ls->source = source; 173 ls->envn = luaS_newliteral(L, LUA_ENV); /* get env name */ 174 luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */ 175 } 176 177 178 179 /* 180 ** ======================================================= 181 ** LEXICAL ANALYZER 182 ** ======================================================= 183 */ 184 185 186 static int check_next1 (LexState *ls, int c) { 187 if (ls->current == c) { 188 next(ls); 189 return 1; 190 } 191 else return 0; 192 } 193 194 195 /* 196 ** Check whether current char is in set 'set' (with two chars) and 197 ** saves it 198 */ 199 static int check_next2 (LexState *ls, const char *set) { 200 lua_assert(set[2] == '\0'); 201 if (ls->current == set[0] || ls->current == set[1]) { 202 save_and_next(ls); 203 return 1; 204 } 205 else return 0; 206 } 207 208 209 /* LUA_NUMBER */ 210 /* 211 ** this function is quite liberal in what it accepts, as 'luaO_str2num' 212 ** will reject ill-formed numerals. 213 */ 214 static int read_numeral (LexState *ls, SemInfo *seminfo) { 215 TValue obj; 216 const char *expo = "Ee"; 217 int first = ls->current; 218 lua_assert(lisdigit(ls->current)); 219 save_and_next(ls); 220 if (first == '0' && check_next2(ls, "xX")) /* hexadecimal? */ 221 expo = "Pp"; 222 for (;;) { 223 if (check_next2(ls, expo)) /* exponent part? */ 224 check_next2(ls, "-+"); /* optional exponent sign */ 225 if (lisxdigit(ls->current)) 226 save_and_next(ls); 227 else if (ls->current == '.') 228 save_and_next(ls); 229 else break; 230 } 231 save(ls, '\0'); 232 if (luaO_str2num(luaZ_buffer(ls->buff), &obj) == 0) /* format error? */ 233 lexerror(ls, "malformed number", TK_FLT); 234 if (ttisinteger(&obj)) { 235 seminfo->i = ivalue(&obj); 236 return TK_INT; 237 } 238 else { 239 lua_assert(ttisfloat(&obj)); 240 seminfo->r = fltvalue(&obj); 241 return TK_FLT; 242 } 243 } 244 245 246 /* 247 ** reads a sequence '[=*[' or ']=*]', leaving the last bracket. 248 ** If sequence is well formed, return its number of '='s + 2; otherwise, 249 ** return 1 if there is no '='s or 0 otherwise (an unfinished '[==...'). 250 */ 251 static size_t skip_sep (LexState *ls) { 252 size_t count = 0; 253 int s = ls->current; 254 lua_assert(s == '[' || s == ']'); 255 save_and_next(ls); 256 while (ls->current == '=') { 257 save_and_next(ls); 258 count++; 259 } 260 return (ls->current == s) ? count + 2 261 : (count == 0) ? 1 262 : 0; 263 264 } 265 266 267 static void read_long_string (LexState *ls, SemInfo *seminfo, size_t sep) { 268 int line = ls->linenumber; /* initial line (for error message) */ 269 save_and_next(ls); /* skip 2nd '[' */ 270 if (currIsNewline(ls)) /* string starts with a newline? */ 271 inclinenumber(ls); /* skip it */ 272 for (;;) { 273 switch (ls->current) { 274 case EOZ: { /* error */ 275 const char *what = (seminfo ? "string" : "comment"); 276 const char *msg = luaO_pushfstring(ls->L, 277 "unfinished long %s (starting at line %d)", what, line); 278 lexerror(ls, msg, TK_EOS); 279 break; /* to avoid warnings */ 280 } 281 case ']': { 282 if (skip_sep(ls) == sep) { 283 save_and_next(ls); /* skip 2nd ']' */ 284 goto endloop; 285 } 286 break; 287 } 288 case '\n': case '\r': { 289 save(ls, '\n'); 290 inclinenumber(ls); 291 if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */ 292 break; 293 } 294 default: { 295 if (seminfo) save_and_next(ls); 296 else next(ls); 297 } 298 } 299 } endloop: 300 if (seminfo) 301 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + sep, 302 luaZ_bufflen(ls->buff) - 2 * sep); 303 } 304 305 306 static void esccheck (LexState *ls, int c, const char *msg) { 307 if (!c) { 308 if (ls->current != EOZ) 309 save_and_next(ls); /* add current to buffer for error message */ 310 lexerror(ls, msg, TK_STRING); 311 } 312 } 313 314 315 static int gethexa (LexState *ls) { 316 save_and_next(ls); 317 esccheck (ls, lisxdigit(ls->current), "hexadecimal digit expected"); 318 return luaO_hexavalue(ls->current); 319 } 320 321 322 static int readhexaesc (LexState *ls) { 323 int r = gethexa(ls); 324 r = (r << 4) + gethexa(ls); 325 luaZ_buffremove(ls->buff, 2); /* remove saved chars from buffer */ 326 return r; 327 } 328 329 330 static unsigned long readutf8esc (LexState *ls) { 331 unsigned long r; 332 int i = 4; /* chars to be removed: '\', 'u', '{', and first digit */ 333 save_and_next(ls); /* skip 'u' */ 334 esccheck(ls, ls->current == '{', "missing '{'"); 335 r = gethexa(ls); /* must have at least one digit */ 336 while ((save_and_next(ls), lisxdigit(ls->current))) { 337 i++; 338 r = (r << 4) + luaO_hexavalue(ls->current); 339 esccheck(ls, r <= 0x10FFFF, "UTF-8 value too large"); 340 } 341 esccheck(ls, ls->current == '}', "missing '}'"); 342 next(ls); /* skip '}' */ 343 luaZ_buffremove(ls->buff, i); /* remove saved chars from buffer */ 344 return r; 345 } 346 347 348 static void utf8esc (LexState *ls) { 349 char buff[UTF8BUFFSZ]; 350 int n = luaO_utf8esc(buff, readutf8esc(ls)); 351 for (; n > 0; n--) /* add 'buff' to string */ 352 save(ls, buff[UTF8BUFFSZ - n]); 353 } 354 355 356 static int readdecesc (LexState *ls) { 357 int i; 358 int r = 0; /* result accumulator */ 359 for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */ 360 r = 10*r + ls->current - '0'; 361 save_and_next(ls); 362 } 363 esccheck(ls, r <= UCHAR_MAX, "decimal escape too large"); 364 luaZ_buffremove(ls->buff, i); /* remove read digits from buffer */ 365 return r; 366 } 367 368 369 static void read_string (LexState *ls, int del, SemInfo *seminfo) { 370 save_and_next(ls); /* keep delimiter (for error messages) */ 371 while (ls->current != del) { 372 switch (ls->current) { 373 case EOZ: 374 lexerror(ls, "unfinished string", TK_EOS); 375 break; /* to avoid warnings */ 376 case '\n': 377 case '\r': 378 lexerror(ls, "unfinished string", TK_STRING); 379 break; /* to avoid warnings */ 380 case '\\': { /* escape sequences */ 381 int c; /* final character to be saved */ 382 save_and_next(ls); /* keep '\\' for error messages */ 383 switch (ls->current) { 384 case 'a': c = '\a'; goto read_save; 385 case 'b': c = '\b'; goto read_save; 386 case 'f': c = '\f'; goto read_save; 387 case 'n': c = '\n'; goto read_save; 388 case 'r': c = '\r'; goto read_save; 389 case 't': c = '\t'; goto read_save; 390 case 'v': c = '\v'; goto read_save; 391 case 'x': c = readhexaesc(ls); goto read_save; 392 case 'u': utf8esc(ls); goto no_save; 393 case '\n': case '\r': 394 inclinenumber(ls); c = '\n'; goto only_save; 395 case '\\': case '\"': case '\'': 396 c = ls->current; goto read_save; 397 case EOZ: goto no_save; /* will raise an error next loop */ 398 case 'z': { /* zap following span of spaces */ 399 luaZ_buffremove(ls->buff, 1); /* remove '\\' */ 400 next(ls); /* skip the 'z' */ 401 while (lisspace(ls->current)) { 402 if (currIsNewline(ls)) inclinenumber(ls); 403 else next(ls); 404 } 405 goto no_save; 406 } 407 default: { 408 esccheck(ls, lisdigit(ls->current), "invalid escape sequence"); 409 c = readdecesc(ls); /* digital escape '\ddd' */ 410 goto only_save; 411 } 412 } 413 read_save: 414 next(ls); 415 /* go through */ 416 only_save: 417 luaZ_buffremove(ls->buff, 1); /* remove '\\' */ 418 save(ls, c); 419 /* go through */ 420 no_save: break; 421 } 422 default: 423 save_and_next(ls); 424 } 425 } 426 save_and_next(ls); /* skip delimiter */ 427 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1, 428 luaZ_bufflen(ls->buff) - 2); 429 } 430 431 432 static int llex (LexState *ls, SemInfo *seminfo) { 433 luaZ_resetbuffer(ls->buff); 434 for (;;) { 435 switch (ls->current) { 436 case '\n': case '\r': { /* line breaks */ 437 inclinenumber(ls); 438 break; 439 } 440 case ' ': case '\f': case '\t': case '\v': { /* spaces */ 441 next(ls); 442 break; 443 } 444 case '-': { /* '-' or '--' (comment) */ 445 next(ls); 446 if (ls->current != '-') return '-'; 447 /* else is a comment */ 448 next(ls); 449 if (ls->current == '[') { /* long comment? */ 450 size_t sep = skip_sep(ls); 451 luaZ_resetbuffer(ls->buff); /* 'skip_sep' may dirty the buffer */ 452 if (sep >= 2) { 453 read_long_string(ls, NULL, sep); /* skip long comment */ 454 luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */ 455 break; 456 } 457 } 458 /* else short comment */ 459 while (!currIsNewline(ls) && ls->current != EOZ) 460 next(ls); /* skip until end of line (or end of file) */ 461 break; 462 } 463 case '[': { /* long string or simply '[' */ 464 size_t sep = skip_sep(ls); 465 if (sep >= 2) { 466 read_long_string(ls, seminfo, sep); 467 return TK_STRING; 468 } 469 else if (sep == 0) /* '[=...' missing second bracket */ 470 lexerror(ls, "invalid long string delimiter", TK_STRING); 471 return '['; 472 } 473 case '=': { 474 next(ls); 475 if (check_next1(ls, '=')) return TK_EQ; 476 else return '='; 477 } 478 case '<': { 479 next(ls); 480 if (check_next1(ls, '=')) return TK_LE; 481 else if (check_next1(ls, '<')) return TK_SHL; 482 else return '<'; 483 } 484 case '>': { 485 next(ls); 486 if (check_next1(ls, '=')) return TK_GE; 487 else if (check_next1(ls, '>')) return TK_SHR; 488 else return '>'; 489 } 490 case '/': { 491 next(ls); 492 if (check_next1(ls, '/')) return TK_IDIV; 493 else return '/'; 494 } 495 case '~': { 496 next(ls); 497 if (check_next1(ls, '=')) return TK_NE; 498 else return '~'; 499 } 500 case ':': { 501 next(ls); 502 if (check_next1(ls, ':')) return TK_DBCOLON; 503 else return ':'; 504 } 505 case '"': case '\'': { /* short literal strings */ 506 read_string(ls, ls->current, seminfo); 507 return TK_STRING; 508 } 509 case '.': { /* '.', '..', '...', or number */ 510 save_and_next(ls); 511 if (check_next1(ls, '.')) { 512 if (check_next1(ls, '.')) 513 return TK_DOTS; /* '...' */ 514 else return TK_CONCAT; /* '..' */ 515 } 516 else if (!lisdigit(ls->current)) return '.'; 517 else return read_numeral(ls, seminfo); 518 } 519 case '0': case '1': case '2': case '3': case '4': 520 case '5': case '6': case '7': case '8': case '9': { 521 return read_numeral(ls, seminfo); 522 } 523 case EOZ: { 524 return TK_EOS; 525 } 526 default: { 527 if (lislalpha(ls->current)) { /* identifier or reserved word? */ 528 TString *ts; 529 do { 530 save_and_next(ls); 531 } while (lislalnum(ls->current)); 532 ts = luaX_newstring(ls, luaZ_buffer(ls->buff), 533 luaZ_bufflen(ls->buff)); 534 seminfo->ts = ts; 535 if (isreserved(ts)) /* reserved word? */ 536 return ts->extra - 1 + FIRST_RESERVED; 537 else { 538 return TK_NAME; 539 } 540 } 541 else { /* single-char tokens (+ - / ...) */ 542 int c = ls->current; 543 next(ls); 544 return c; 545 } 546 } 547 } 548 } 549 } 550 551 552 void luaX_next (LexState *ls) { 553 ls->lastline = ls->linenumber; 554 if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */ 555 ls->t = ls->lookahead; /* use this one */ 556 ls->lookahead.token = TK_EOS; /* and discharge it */ 557 } 558 else 559 ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */ 560 } 561 562 563 int luaX_lookahead (LexState *ls) { 564 lua_assert(ls->lookahead.token == TK_EOS); 565 ls->lookahead.token = llex(ls, &ls->lookahead.seminfo); 566 return ls->lookahead.token; 567 } 568