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| 1 /* |
| 2 ** $Id: llex.c,v 2.63 2013/03/16 21:10:18 roberto Exp $ |
| 3 ** Lexical Analyzer |
| 4 ** See Copyright Notice in lua.h |
| 5 */ |
| 6 |
| 7 |
| 8 #include <locale.h> |
| 9 #include <string.h> |
| 10 |
| 11 #define llex_c |
| 12 #define LUA_CORE |
| 13 |
| 14 #include "lua.h" |
| 15 |
| 16 #include "lctype.h" |
| 17 #include "ldo.h" |
| 18 #include "llex.h" |
| 19 #include "lobject.h" |
| 20 #include "lparser.h" |
| 21 #include "lstate.h" |
| 22 #include "lstring.h" |
| 23 #include "ltable.h" |
| 24 #include "lzio.h" |
| 25 |
| 26 |
| 27 |
| 28 #define next(ls) (ls->current = zgetc(ls->z)) |
| 29 |
| 30 |
| 31 |
| 32 #define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r') |
| 33 |
| 34 |
| 35 /* ORDER RESERVED */ |
| 36 static const char *const luaX_tokens [] = { |
| 37 "and", "break", "do", "else", "elseif", |
| 38 "end", "false", "for", "function", "goto", "if", |
| 39 "in", "local", "nil", "not", "or", "repeat", |
| 40 "return", "then", "true", "until", "while", |
| 41 "..", "...", "==", ">=", "<=", "~=", "::", "<eof>", |
| 42 "<number>", "<name>", "<string>" |
| 43 }; |
| 44 |
| 45 |
| 46 #define save_and_next(ls) (save(ls, ls->current), next(ls)) |
| 47 |
| 48 |
| 49 static l_noret lexerror (LexState *ls, const char *msg, int token); |
| 50 |
| 51 |
| 52 static void save (LexState *ls, int c) { |
| 53 Mbuffer *b = ls->buff; |
| 54 if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) { |
| 55 size_t newsize; |
| 56 if (luaZ_sizebuffer(b) >= MAX_SIZET/2) |
| 57 lexerror(ls, "lexical element too long", 0); |
| 58 newsize = luaZ_sizebuffer(b) * 2; |
| 59 luaZ_resizebuffer(ls->L, b, newsize); |
| 60 } |
| 61 b->buffer[luaZ_bufflen(b)++] = cast(char, c); |
| 62 } |
| 63 |
| 64 |
| 65 void luaX_init (lua_State *L) { |
| 66 int i; |
| 67 for (i=0; i<NUM_RESERVED; i++) { |
| 68 TString *ts = luaS_new(L, luaX_tokens[i]); |
| 69 luaS_fix(ts); /* reserved words are never collected */ |
| 70 ts->tsv.extra = cast_byte(i+1); /* reserved word */ |
| 71 } |
| 72 } |
| 73 |
| 74 |
| 75 const char *luaX_token2str (LexState *ls, int token) { |
| 76 if (token < FIRST_RESERVED) { /* single-byte symbols? */ |
| 77 lua_assert(token == cast(unsigned char, token)); |
| 78 return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) : |
| 79 luaO_pushfstring(ls->L, "char(%d)", token); |
| 80 } |
| 81 else { |
| 82 const char *s = luaX_tokens[token - FIRST_RESERVED]; |
| 83 if (token < TK_EOS) /* fixed format (symbols and reserved words)? */ |
| 84 return luaO_pushfstring(ls->L, LUA_QS, s); |
| 85 else /* names, strings, and numerals */ |
| 86 return s; |
| 87 } |
| 88 } |
| 89 |
| 90 |
| 91 static const char *txtToken (LexState *ls, int token) { |
| 92 switch (token) { |
| 93 case TK_NAME: |
| 94 case TK_STRING: |
| 95 case TK_NUMBER: |
| 96 save(ls, '\0'); |
| 97 return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff)); |
| 98 default: |
| 99 return luaX_token2str(ls, token); |
| 100 } |
| 101 } |
| 102 |
| 103 |
| 104 static l_noret lexerror (LexState *ls, const char *msg, int token) { |
| 105 char buff[LUA_IDSIZE]; |
| 106 luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE); |
| 107 msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg); |
| 108 if (token) |
| 109 luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token)); |
| 110 luaD_throw(ls->L, LUA_ERRSYNTAX); |
| 111 } |
| 112 |
| 113 |
| 114 l_noret luaX_syntaxerror (LexState *ls, const char *msg) { |
| 115 lexerror(ls, msg, ls->t.token); |
| 116 } |
| 117 |
| 118 |
| 119 /* |
| 120 ** creates a new string and anchors it in function's table so that |
| 121 ** it will not be collected until the end of the function's compilation |
| 122 ** (by that time it should be anchored in function's prototype) |
| 123 */ |
| 124 TString *luaX_newstring (LexState *ls, const char *str, size_t l) { |
| 125 lua_State *L = ls->L; |
| 126 TValue *o; /* entry for `str' */ |
| 127 TString *ts = luaS_newlstr(L, str, l); /* create new string */ |
| 128 setsvalue2s(L, L->top++, ts); /* temporarily anchor it in stack */ |
| 129 o = luaH_set(L, ls->fs->h, L->top - 1); |
| 130 if (ttisnil(o)) { /* not in use yet? (see 'addK') */ |
| 131 /* boolean value does not need GC barrier; |
| 132 table has no metatable, so it does not need to invalidate cache */ |
| 133 setbvalue(o, 1); /* t[string] = true */ |
| 134 luaC_checkGC(L); |
| 135 } |
| 136 L->top--; /* remove string from stack */ |
| 137 return ts; |
| 138 } |
| 139 |
| 140 |
| 141 /* |
| 142 ** increment line number and skips newline sequence (any of |
| 143 ** \n, \r, \n\r, or \r\n) |
| 144 */ |
| 145 static void inclinenumber (LexState *ls) { |
| 146 int old = ls->current; |
| 147 lua_assert(currIsNewline(ls)); |
| 148 next(ls); /* skip `\n' or `\r' */ |
| 149 if (currIsNewline(ls) && ls->current != old) |
| 150 next(ls); /* skip `\n\r' or `\r\n' */ |
| 151 if (++ls->linenumber >= MAX_INT) |
| 152 luaX_syntaxerror(ls, "chunk has too many lines"); |
| 153 } |
| 154 |
| 155 |
| 156 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source, |
| 157 int firstchar) { |
| 158 ls->decpoint = '.'; |
| 159 ls->L = L; |
| 160 ls->current = firstchar; |
| 161 ls->lookahead.token = TK_EOS; /* no look-ahead token */ |
| 162 ls->z = z; |
| 163 ls->fs = NULL; |
| 164 ls->linenumber = 1; |
| 165 ls->lastline = 1; |
| 166 ls->source = source; |
| 167 ls->envn = luaS_new(L, LUA_ENV); /* create env name */ |
| 168 luaS_fix(ls->envn); /* never collect this name */ |
| 169 luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */ |
| 170 } |
| 171 |
| 172 |
| 173 |
| 174 /* |
| 175 ** ======================================================= |
| 176 ** LEXICAL ANALYZER |
| 177 ** ======================================================= |
| 178 */ |
| 179 |
| 180 |
| 181 |
| 182 static int check_next (LexState *ls, const char *set) { |
| 183 if (ls->current == '\0' || !strchr(set, ls->current)) |
| 184 return 0; |
| 185 save_and_next(ls); |
| 186 return 1; |
| 187 } |
| 188 |
| 189 |
| 190 /* |
| 191 ** change all characters 'from' in buffer to 'to' |
| 192 */ |
| 193 static void buffreplace (LexState *ls, char from, char to) { |
| 194 size_t n = luaZ_bufflen(ls->buff); |
| 195 char *p = luaZ_buffer(ls->buff); |
| 196 while (n--) |
| 197 if (p[n] == from) p[n] = to; |
| 198 } |
| 199 |
| 200 |
| 201 #if !defined(getlocaledecpoint) |
| 202 #define getlocaledecpoint() (localeconv()->decimal_point[0]) |
| 203 #endif |
| 204 |
| 205 |
| 206 #define buff2d(b,e) luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e) |
| 207 |
| 208 /* |
| 209 ** in case of format error, try to change decimal point separator to |
| 210 ** the one defined in the current locale and check again |
| 211 */ |
| 212 static void trydecpoint (LexState *ls, SemInfo *seminfo) { |
| 213 char old = ls->decpoint; |
| 214 ls->decpoint = getlocaledecpoint(); |
| 215 buffreplace(ls, old, ls->decpoint); /* try new decimal separator */ |
| 216 if (!buff2d(ls->buff, &seminfo->r)) { |
| 217 /* format error with correct decimal point: no more options */ |
| 218 buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */ |
| 219 lexerror(ls, "malformed number", TK_NUMBER); |
| 220 } |
| 221 } |
| 222 |
| 223 |
| 224 /* LUA_NUMBER */ |
| 225 /* |
| 226 ** this function is quite liberal in what it accepts, as 'luaO_str2d' |
| 227 ** will reject ill-formed numerals. |
| 228 */ |
| 229 static void read_numeral (LexState *ls, SemInfo *seminfo) { |
| 230 const char *expo = "Ee"; |
| 231 int first = ls->current; |
| 232 lua_assert(lisdigit(ls->current)); |
| 233 save_and_next(ls); |
| 234 if (first == '0' && check_next(ls, "Xx")) /* hexadecimal? */ |
| 235 expo = "Pp"; |
| 236 for (;;) { |
| 237 if (check_next(ls, expo)) /* exponent part? */ |
| 238 check_next(ls, "+-"); /* optional exponent sign */ |
| 239 if (lisxdigit(ls->current) || ls->current == '.') |
| 240 save_and_next(ls); |
| 241 else break; |
| 242 } |
| 243 save(ls, '\0'); |
| 244 buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */ |
| 245 if (!buff2d(ls->buff, &seminfo->r)) /* format error? */ |
| 246 trydecpoint(ls, seminfo); /* try to update decimal point separator */ |
| 247 } |
| 248 |
| 249 |
| 250 /* |
| 251 ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or |
| 252 ** -1 if sequence is malformed |
| 253 */ |
| 254 static int skip_sep (LexState *ls) { |
| 255 int count = 0; |
| 256 int s = ls->current; |
| 257 lua_assert(s == '[' || s == ']'); |
| 258 save_and_next(ls); |
| 259 while (ls->current == '=') { |
| 260 save_and_next(ls); |
| 261 count++; |
| 262 } |
| 263 return (ls->current == s) ? count : (-count) - 1; |
| 264 } |
| 265 |
| 266 |
| 267 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) { |
| 268 save_and_next(ls); /* skip 2nd `[' */ |
| 269 if (currIsNewline(ls)) /* string starts with a newline? */ |
| 270 inclinenumber(ls); /* skip it */ |
| 271 for (;;) { |
| 272 switch (ls->current) { |
| 273 case EOZ: |
| 274 lexerror(ls, (seminfo) ? "unfinished long string" : |
| 275 "unfinished long comment", TK_EOS); |
| 276 break; /* to avoid warnings */ |
| 277 case ']': { |
| 278 if (skip_sep(ls) == sep) { |
| 279 save_and_next(ls); /* skip 2nd `]' */ |
| 280 goto endloop; |
| 281 } |
| 282 break; |
| 283 } |
| 284 case '\n': case '\r': { |
| 285 save(ls, '\n'); |
| 286 inclinenumber(ls); |
| 287 if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */ |
| 288 break; |
| 289 } |
| 290 default: { |
| 291 if (seminfo) save_and_next(ls); |
| 292 else next(ls); |
| 293 } |
| 294 } |
| 295 } endloop: |
| 296 if (seminfo) |
| 297 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep), |
| 298 luaZ_bufflen(ls->buff) - 2*(2 + sep)); |
| 299 } |
| 300 |
| 301 |
| 302 static void escerror (LexState *ls, int *c, int n, const char *msg) { |
| 303 int i; |
| 304 luaZ_resetbuffer(ls->buff); /* prepare error message */ |
| 305 save(ls, '\\'); |
| 306 for (i = 0; i < n && c[i] != EOZ; i++) |
| 307 save(ls, c[i]); |
| 308 lexerror(ls, msg, TK_STRING); |
| 309 } |
| 310 |
| 311 |
| 312 static int readhexaesc (LexState *ls) { |
| 313 int c[3], i; /* keep input for error message */ |
| 314 int r = 0; /* result accumulator */ |
| 315 c[0] = 'x'; /* for error message */ |
| 316 for (i = 1; i < 3; i++) { /* read two hexadecimal digits */ |
| 317 c[i] = next(ls); |
| 318 if (!lisxdigit(c[i])) |
| 319 escerror(ls, c, i + 1, "hexadecimal digit expected"); |
| 320 r = (r << 4) + luaO_hexavalue(c[i]); |
| 321 } |
| 322 return r; |
| 323 } |
| 324 |
| 325 |
| 326 static int readdecesc (LexState *ls) { |
| 327 int c[3], i; |
| 328 int r = 0; /* result accumulator */ |
| 329 for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */ |
| 330 c[i] = ls->current; |
| 331 r = 10*r + c[i] - '0'; |
| 332 next(ls); |
| 333 } |
| 334 if (r > UCHAR_MAX) |
| 335 escerror(ls, c, i, "decimal escape too large"); |
| 336 return r; |
| 337 } |
| 338 |
| 339 |
| 340 static void read_string (LexState *ls, int del, SemInfo *seminfo) { |
| 341 save_and_next(ls); /* keep delimiter (for error messages) */ |
| 342 while (ls->current != del) { |
| 343 switch (ls->current) { |
| 344 case EOZ: |
| 345 lexerror(ls, "unfinished string", TK_EOS); |
| 346 break; /* to avoid warnings */ |
| 347 case '\n': |
| 348 case '\r': |
| 349 lexerror(ls, "unfinished string", TK_STRING); |
| 350 break; /* to avoid warnings */ |
| 351 case '\\': { /* escape sequences */ |
| 352 int c; /* final character to be saved */ |
| 353 next(ls); /* do not save the `\' */ |
| 354 switch (ls->current) { |
| 355 case 'a': c = '\a'; goto read_save; |
| 356 case 'b': c = '\b'; goto read_save; |
| 357 case 'f': c = '\f'; goto read_save; |
| 358 case 'n': c = '\n'; goto read_save; |
| 359 case 'r': c = '\r'; goto read_save; |
| 360 case 't': c = '\t'; goto read_save; |
| 361 case 'v': c = '\v'; goto read_save; |
| 362 case 'x': c = readhexaesc(ls); goto read_save; |
| 363 case '\n': case '\r': |
| 364 inclinenumber(ls); c = '\n'; goto only_save; |
| 365 case '\\': case '\"': case '\'': |
| 366 c = ls->current; goto read_save; |
| 367 case EOZ: goto no_save; /* will raise an error next loop */ |
| 368 case 'z': { /* zap following span of spaces */ |
| 369 next(ls); /* skip the 'z' */ |
| 370 while (lisspace(ls->current)) { |
| 371 if (currIsNewline(ls)) inclinenumber(ls); |
| 372 else next(ls); |
| 373 } |
| 374 goto no_save; |
| 375 } |
| 376 default: { |
| 377 if (!lisdigit(ls->current)) |
| 378 escerror(ls, &ls->current, 1, "invalid escape sequence"); |
| 379 /* digital escape \ddd */ |
| 380 c = readdecesc(ls); |
| 381 goto only_save; |
| 382 } |
| 383 } |
| 384 read_save: next(ls); /* read next character */ |
| 385 only_save: save(ls, c); /* save 'c' */ |
| 386 no_save: break; |
| 387 } |
| 388 default: |
| 389 save_and_next(ls); |
| 390 } |
| 391 } |
| 392 save_and_next(ls); /* skip delimiter */ |
| 393 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1, |
| 394 luaZ_bufflen(ls->buff) - 2); |
| 395 } |
| 396 |
| 397 |
| 398 static int llex (LexState *ls, SemInfo *seminfo) { |
| 399 luaZ_resetbuffer(ls->buff); |
| 400 for (;;) { |
| 401 switch (ls->current) { |
| 402 case '\n': case '\r': { /* line breaks */ |
| 403 inclinenumber(ls); |
| 404 break; |
| 405 } |
| 406 case ' ': case '\f': case '\t': case '\v': { /* spaces */ |
| 407 next(ls); |
| 408 break; |
| 409 } |
| 410 case '-': { /* '-' or '--' (comment) */ |
| 411 next(ls); |
| 412 if (ls->current != '-') return '-'; |
| 413 /* else is a comment */ |
| 414 next(ls); |
| 415 if (ls->current == '[') { /* long comment? */ |
| 416 int sep = skip_sep(ls); |
| 417 luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */ |
| 418 if (sep >= 0) { |
| 419 read_long_string(ls, NULL, sep); /* skip long comment */ |
| 420 luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */ |
| 421 break; |
| 422 } |
| 423 } |
| 424 /* else short comment */ |
| 425 while (!currIsNewline(ls) && ls->current != EOZ) |
| 426 next(ls); /* skip until end of line (or end of file) */ |
| 427 break; |
| 428 } |
| 429 case '[': { /* long string or simply '[' */ |
| 430 int sep = skip_sep(ls); |
| 431 if (sep >= 0) { |
| 432 read_long_string(ls, seminfo, sep); |
| 433 return TK_STRING; |
| 434 } |
| 435 else if (sep == -1) return '['; |
| 436 else lexerror(ls, "invalid long string delimiter", TK_STRING); |
| 437 } |
| 438 case '=': { |
| 439 next(ls); |
| 440 if (ls->current != '=') return '='; |
| 441 else { next(ls); return TK_EQ; } |
| 442 } |
| 443 case '<': { |
| 444 next(ls); |
| 445 if (ls->current != '=') return '<'; |
| 446 else { next(ls); return TK_LE; } |
| 447 } |
| 448 case '>': { |
| 449 next(ls); |
| 450 if (ls->current != '=') return '>'; |
| 451 else { next(ls); return TK_GE; } |
| 452 } |
| 453 case '~': { |
| 454 next(ls); |
| 455 if (ls->current != '=') return '~'; |
| 456 else { next(ls); return TK_NE; } |
| 457 } |
| 458 case ':': { |
| 459 next(ls); |
| 460 if (ls->current != ':') return ':'; |
| 461 else { next(ls); return TK_DBCOLON; } |
| 462 } |
| 463 case '"': case '\'': { /* short literal strings */ |
| 464 read_string(ls, ls->current, seminfo); |
| 465 return TK_STRING; |
| 466 } |
| 467 case '.': { /* '.', '..', '...', or number */ |
| 468 save_and_next(ls); |
| 469 if (check_next(ls, ".")) { |
| 470 if (check_next(ls, ".")) |
| 471 return TK_DOTS; /* '...' */ |
| 472 else return TK_CONCAT; /* '..' */ |
| 473 } |
| 474 else if (!lisdigit(ls->current)) return '.'; |
| 475 /* else go through */ |
| 476 } |
| 477 case '0': case '1': case '2': case '3': case '4': |
| 478 case '5': case '6': case '7': case '8': case '9': { |
| 479 read_numeral(ls, seminfo); |
| 480 return TK_NUMBER; |
| 481 } |
| 482 case EOZ: { |
| 483 return TK_EOS; |
| 484 } |
| 485 default: { |
| 486 if (lislalpha(ls->current)) { /* identifier or reserved word? */ |
| 487 TString *ts; |
| 488 do { |
| 489 save_and_next(ls); |
| 490 } while (lislalnum(ls->current)); |
| 491 ts = luaX_newstring(ls, luaZ_buffer(ls->buff), |
| 492 luaZ_bufflen(ls->buff)); |
| 493 seminfo->ts = ts; |
| 494 if (isreserved(ts)) /* reserved word? */ |
| 495 return ts->tsv.extra - 1 + FIRST_RESERVED; |
| 496 else { |
| 497 return TK_NAME; |
| 498 } |
| 499 } |
| 500 else { /* single-char tokens (+ - / ...) */ |
| 501 int c = ls->current; |
| 502 next(ls); |
| 503 return c; |
| 504 } |
| 505 } |
| 506 } |
| 507 } |
| 508 } |
| 509 |
| 510 |
| 511 void luaX_next (LexState *ls) { |
| 512 ls->lastline = ls->linenumber; |
| 513 if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */ |
| 514 ls->t = ls->lookahead; /* use this one */ |
| 515 ls->lookahead.token = TK_EOS; /* and discharge it */ |
| 516 } |
| 517 else |
| 518 ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */ |
| 519 } |
| 520 |
| 521 |
| 522 int luaX_lookahead (LexState *ls) { |
| 523 lua_assert(ls->lookahead.token == TK_EOS); |
| 524 ls->lookahead.token = llex(ls, &ls->lookahead.seminfo); |
| 525 return ls->lookahead.token; |
| 526 } |
| 527 |
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