com32/lua/src/llex.c

   1 /*
   2 ** $Id: llex.c,v 2.63.1.2 2013/08/30 15:49:41 roberto Exp $
   3 ** Lexical Analyzer
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #ifndef SYSLINUX
   9 #include <locale.h>
  10 #else
  11 #define getlocaledecpoint() '.'
  12 #endif
  13 #include <string.h>
  14
  15 #define llex_c
  16 #define LUA_CORE
  17
  18 #include "lua.h"
  19
  20 #include "lctype.h"
  21 #include "ldo.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     "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
  46     "<number>", "<name>", "<string>"
  47 };
  48
  49
  50 #define save_and_next(ls) (save(ls, ls->current), next(ls))
  51
  52
  53 static l_noret lexerror (LexState *ls, const char *msg, int token);
  54
  55
  56 static void save (LexState *ls, int c) {
  57   Mbuffer *b = ls->buff;
  58   if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
  59     size_t newsize;
  60     if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
  61       lexerror(ls, "lexical element too long", 0);
  62     newsize = luaZ_sizebuffer(b) * 2;
  63     luaZ_resizebuffer(ls->L, b, newsize);
  64   }
  65   b->buffer[luaZ_bufflen(b)++] = cast(char, c);
  66 }
  67
  68
  69 void luaX_init (lua_State *L) {
  70   int i;
  71   for (i=0; i<NUM_RESERVED; i++) {
  72     TString *ts = luaS_new(L, luaX_tokens[i]);
  73     luaS_fix(ts);  /* reserved words are never collected */
  74     ts->tsv.extra = cast_byte(i+1);  /* reserved word */
  75   }
  76 }
  77
  78
  79 const char *luaX_token2str (LexState *ls, int token) {
  80   if (token < FIRST_RESERVED) {  /* single-byte symbols? */
  81     lua_assert(token == cast(unsigned char, token));
  82     return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
  83                               luaO_pushfstring(ls->L, "char(%d)", token);
  84   }
  85   else {
  86     const char *s = luaX_tokens[token - FIRST_RESERVED];
  87     if (token < TK_EOS)  /* fixed format (symbols and reserved words)? */
  88       return luaO_pushfstring(ls->L, LUA_QS, s);
  89     else  /* names, strings, and numerals */
  90       return s;
  91   }
  92 }
  93
  94
  95 static const char *txtToken (LexState *ls, int token) {
  96   switch (token) {
  97     case TK_NAME:
  98     case TK_STRING:
  99     case TK_NUMBER:
 100       save(ls, '\0');
 101       return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
 102     default:
 103       return luaX_token2str(ls, token);
 104   }
 105 }
 106
 107
 108 static l_noret lexerror (LexState *ls, const char *msg, int token) {
 109   char buff[LUA_IDSIZE];
 110   luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
 111   msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
 112   if (token)
 113     luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
 114   luaD_throw(ls->L, LUA_ERRSYNTAX);
 115 }
 116
 117
 118 l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
 119   lexerror(ls, msg, ls->t.token);
 120 }
 121
 122
 123 /*
 124 ** creates a new string and anchors it in function's table so that
 125 ** it will not be collected until the end of the function's compilation
 126 ** (by that time it should be anchored in function's prototype)
 127 */
 128 TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
 129   lua_State *L = ls->L;
 130   TValue *o;  /* entry for `str' */
 131   TString *ts = luaS_newlstr(L, str, l);  /* create new string */
 132   setsvalue2s(L, L->top++, ts);  /* temporarily anchor it in stack */
 133   o = luaH_set(L, ls->fs->h, L->top - 1);
 134   if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
 135     /* boolean value does not need GC barrier;
 136        table has no metatable, so it does not need to invalidate cache */
 137     setbvalue(o, 1);  /* t[string] = true */
 138     luaC_checkGC(L);
 139   }
 140   else {  /* string already present */
 141     ts = rawtsvalue(keyfromval(o));  /* re-use value previously stored */
 142   }
 143   L->top--;  /* remove string from stack */
 144   return ts;
 145 }
 146
 147
 148 /*
 149 ** increment line number and skips newline sequence (any of
 150 ** \n, \r, \n\r, or \r\n)
 151 */
 152 static void inclinenumber (LexState *ls) {
 153   int old = ls->current;
 154   lua_assert(currIsNewline(ls));
 155   next(ls);  /* skip `\n' or `\r' */
 156   if (currIsNewline(ls) && ls->current != old)
 157     next(ls);  /* skip `\n\r' or `\r\n' */
 158   if (++ls->linenumber >= MAX_INT)
 159     luaX_syntaxerror(ls, "chunk has too many lines");
 160 }
 161
 162
 163 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
 164                     int firstchar) {
 165   ls->decpoint = '.';
 166   ls->L = L;
 167   ls->current = firstchar;
 168   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
 169   ls->z = z;
 170   ls->fs = NULL;
 171   ls->linenumber = 1;
 172   ls->lastline = 1;
 173   ls->source = source;
 174   ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
 175   luaS_fix(ls->envn);  /* never collect this name */
 176   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
 177 }
 178
 179
 180
 181 /*
 182 ** =======================================================
 183 ** LEXICAL ANALYZER
 184 ** =======================================================
 185 */
 186
 187
 188
 189 static int check_next (LexState *ls, const char *set) {
 190   if (ls->current == '\0' || !strchr(set, ls->current))
 191     return 0;
 192   save_and_next(ls);
 193   return 1;
 194 }
 195
 196
 197 /*
 198 ** change all characters 'from' in buffer to 'to'
 199 */
 200 static void buffreplace (LexState *ls, char from, char to) {
 201   size_t n = luaZ_bufflen(ls->buff);
 202   char *p = luaZ_buffer(ls->buff);
 203   while (n--)
 204     if (p[n] == from) p[n] = to;
 205 }
 206
 207
 208 #if !defined(getlocaledecpoint)
 209 #define getlocaledecpoint()     (localeconv()->decimal_point[0])
 210 #endif
 211
 212
 213 #define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
 214
 215 /*
 216 ** in case of format error, try to change decimal point separator to
 217 ** the one defined in the current locale and check again
 218 */
 219 static void trydecpoint (LexState *ls, SemInfo *seminfo) {
 220   char old = ls->decpoint;
 221   ls->decpoint = getlocaledecpoint();
 222   buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
 223   if (!buff2d(ls->buff, &seminfo->r)) {
 224     /* format error with correct decimal point: no more options */
 225     buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
 226     lexerror(ls, "malformed number", TK_NUMBER);
 227   }
 228 }
 229
 230
 231 /* LUA_NUMBER */
 232 /*
 233 ** this function is quite liberal in what it accepts, as 'luaO_str2d'
 234 ** will reject ill-formed numerals.
 235 */
 236 static void read_numeral (LexState *ls, SemInfo *seminfo) {
 237   const char *expo = "Ee";
 238   int first = ls->current;
 239   lua_assert(lisdigit(ls->current));
 240   save_and_next(ls);
 241   if (first == '0' && check_next(ls, "Xx"))  /* hexadecimal? */
 242     expo = "Pp";
 243   for (;;) {
 244     if (check_next(ls, expo))  /* exponent part? */
 245       check_next(ls, "+-");  /* optional exponent sign */
 246     if (lisxdigit(ls->current) || ls->current == '.')
 247       save_and_next(ls);
 248     else  break;
 249   }
 250   save(ls, '\0');
 251   buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
 252   if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
 253     trydecpoint(ls, seminfo); /* try to update decimal point separator */
 254 }
 255
 256
 257 /*
 258 ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
 259 ** -1 if sequence is malformed
 260 */
 261 static int skip_sep (LexState *ls) {
 262   int count = 0;
 263   int s = ls->current;
 264   lua_assert(s == '[' || s == ']');
 265   save_and_next(ls);
 266   while (ls->current == '=') {
 267     save_and_next(ls);
 268     count++;
 269   }
 270   return (ls->current == s) ? count : (-count) - 1;
 271 }
 272
 273
 274 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
 275   save_and_next(ls);  /* skip 2nd `[' */
 276   if (currIsNewline(ls))  /* string starts with a newline? */
 277     inclinenumber(ls);  /* skip it */
 278   for (;;) {
 279     switch (ls->current) {
 280       case EOZ:
 281         lexerror(ls, (seminfo) ? "unfinished long string" :
 282                                  "unfinished long comment", TK_EOS);
 283         break;  /* to avoid warnings */
 284       case ']': {
 285         if (skip_sep(ls) == sep) {
 286           save_and_next(ls);  /* skip 2nd `]' */
 287           goto endloop;
 288         }
 289         break;
 290       }
 291       case '\n': case '\r': {
 292         save(ls, '\n');
 293         inclinenumber(ls);
 294         if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
 295         break;
 296       }
 297       default: {
 298         if (seminfo) save_and_next(ls);
 299         else next(ls);
 300       }
 301     }
 302   } endloop:
 303   if (seminfo)
 304     seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
 305                                      luaZ_bufflen(ls->buff) - 2*(2 + sep));
 306 }
 307
 308
 309 static void escerror (LexState *ls, int *c, int n, const char *msg) {
 310   int i;
 311   luaZ_resetbuffer(ls->buff);  /* prepare error message */
 312   save(ls, '\\');
 313   for (i = 0; i < n && c[i] != EOZ; i++)
 314     save(ls, c[i]);
 315   lexerror(ls, msg, TK_STRING);
 316 }
 317
 318
 319 static int readhexaesc (LexState *ls) {
 320   int c[3], i;  /* keep input for error message */
 321   int r = 0;  /* result accumulator */
 322   c[0] = 'x';  /* for error message */
 323   for (i = 1; i < 3; i++) {  /* read two hexadecimal digits */
 324     c[i] = next(ls);
 325     if (!lisxdigit(c[i]))
 326       escerror(ls, c, i + 1, "hexadecimal digit expected");
 327     r = (r << 4) + luaO_hexavalue(c[i]);
 328   }
 329   return r;
 330 }
 331
 332
 333 static int readdecesc (LexState *ls) {
 334   int c[3], i;
 335   int r = 0;  /* result accumulator */
 336   for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
 337     c[i] = ls->current;
 338     r = 10*r + c[i] - '0';
 339     next(ls);
 340   }
 341   if (r > UCHAR_MAX)
 342     escerror(ls, c, i, "decimal escape too large");
 343   return r;
 344 }
 345
 346
 347 static void read_string (LexState *ls, int del, SemInfo *seminfo) {
 348   save_and_next(ls);  /* keep delimiter (for error messages) */
 349   while (ls->current != del) {
 350     switch (ls->current) {
 351       case EOZ:
 352         lexerror(ls, "unfinished string", TK_EOS);
 353         break;  /* to avoid warnings */
 354       case '\n':
 355       case '\r':
 356         lexerror(ls, "unfinished string", TK_STRING);
 357         break;  /* to avoid warnings */
 358       case '\\': {  /* escape sequences */
 359         int c;  /* final character to be saved */
 360         next(ls);  /* do not save the `\' */
 361         switch (ls->current) {
 362           case 'a': c = '\a'; goto read_save;
 363           case 'b': c = '\b'; goto read_save;
 364           case 'f': c = '\f'; goto read_save;
 365           case 'n': c = '\n'; goto read_save;
 366           case 'r': c = '\r'; goto read_save;
 367           case 't': c = '\t'; goto read_save;
 368           case 'v': c = '\v'; goto read_save;
 369           case 'x': c = readhexaesc(ls); goto read_save;
 370           case '\n': case '\r':
 371             inclinenumber(ls); c = '\n'; goto only_save;
 372           case '\\': case '\"': case '\'':
 373             c = ls->current; goto read_save;
 374           case EOZ: goto no_save;  /* will raise an error next loop */
 375           case 'z': {  /* zap following span of spaces */
 376             next(ls);  /* skip the 'z' */
 377             while (lisspace(ls->current)) {
 378               if (currIsNewline(ls)) inclinenumber(ls);
 379               else next(ls);
 380             }
 381             goto no_save;
 382           }
 383           default: {
 384             if (!lisdigit(ls->current))
 385               escerror(ls, &ls->current, 1, "invalid escape sequence");
 386             /* digital escape \ddd */
 387             c = readdecesc(ls);
 388             goto only_save;
 389           }
 390         }
 391        read_save: next(ls);  /* read next character */
 392        only_save: save(ls, c);  /* save 'c' */
 393        no_save: break;
 394       }
 395       default:
 396         save_and_next(ls);
 397     }
 398   }
 399   save_and_next(ls);  /* skip delimiter */
 400   seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
 401                                    luaZ_bufflen(ls->buff) - 2);
 402 }
 403
 404
 405 static int llex (LexState *ls, SemInfo *seminfo) {
 406   luaZ_resetbuffer(ls->buff);
 407   for (;;) {
 408     switch (ls->current) {
 409       case '\n': case '\r': {  /* line breaks */
 410         inclinenumber(ls);
 411         break;
 412       }
 413       case ' ': case '\f': case '\t': case '\v': {  /* spaces */
 414         next(ls);
 415         break;
 416       }
 417       case '-': {  /* '-' or '--' (comment) */
 418         next(ls);
 419         if (ls->current != '-') return '-';
 420         /* else is a comment */
 421         next(ls);
 422         if (ls->current == '[') {  /* long comment? */
 423           int sep = skip_sep(ls);
 424           luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
 425           if (sep >= 0) {
 426             read_long_string(ls, NULL, sep);  /* skip long comment */
 427             luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
 428             break;
 429           }
 430         }
 431         /* else short comment */
 432         while (!currIsNewline(ls) && ls->current != EOZ)
 433           next(ls);  /* skip until end of line (or end of file) */
 434         break;
 435       }
 436       case '[': {  /* long string or simply '[' */
 437         int sep = skip_sep(ls);
 438         if (sep >= 0) {
 439           read_long_string(ls, seminfo, sep);
 440           return TK_STRING;
 441         }
 442         else if (sep == -1) return '[';
 443         else lexerror(ls, "invalid long string delimiter", TK_STRING);
 444       }
 445       case '=': {
 446         next(ls);
 447         if (ls->current != '=') return '=';
 448         else { next(ls); return TK_EQ; }
 449       }
 450       case '<': {
 451         next(ls);
 452         if (ls->current != '=') return '<';
 453         else { next(ls); return TK_LE; }
 454       }
 455       case '>': {
 456         next(ls);
 457         if (ls->current != '=') return '>';
 458         else { next(ls); return TK_GE; }
 459       }
 460       case '~': {
 461         next(ls);
 462         if (ls->current != '=') return '~';
 463         else { next(ls); return TK_NE; }
 464       }
 465       case ':': {
 466         next(ls);
 467         if (ls->current != ':') return ':';
 468         else { next(ls); return TK_DBCOLON; }
 469       }
 470       case '"': case '\'': {  /* short literal strings */
 471         read_string(ls, ls->current, seminfo);
 472         return TK_STRING;
 473       }
 474       case '.': {  /* '.', '..', '...', or number */
 475         save_and_next(ls);
 476         if (check_next(ls, ".")) {
 477           if (check_next(ls, "."))
 478             return TK_DOTS;   /* '...' */
 479           else return TK_CONCAT;   /* '..' */
 480         }
 481         else if (!lisdigit(ls->current)) return '.';
 482         /* else go through */
 483       }
 484       case '0': case '1': case '2': case '3': case '4':
 485       case '5': case '6': case '7': case '8': case '9': {
 486         read_numeral(ls, seminfo);
 487         return TK_NUMBER;
 488       }
 489       case EOZ: {
 490         return TK_EOS;
 491       }
 492       default: {
 493         if (lislalpha(ls->current)) {  /* identifier or reserved word? */
 494           TString *ts;
 495           do {
 496             save_and_next(ls);
 497           } while (lislalnum(ls->current));
 498           ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
 499                                   luaZ_bufflen(ls->buff));
 500           seminfo->ts = ts;
 501           if (isreserved(ts))  /* reserved word? */
 502             return ts->tsv.extra - 1 + FIRST_RESERVED;
 503           else {
 504             return TK_NAME;
 505           }
 506         }
 507         else {  /* single-char tokens (+ - / ...) */
 508           int c = ls->current;
 509           next(ls);
 510           return c;
 511         }
 512       }
 513     }
 514   }
 515 }
 516
 517
 518 void luaX_next (LexState *ls) {
 519   ls->lastline = ls->linenumber;
 520   if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
 521     ls->t = ls->lookahead;  /* use this one */
 522     ls->lookahead.token = TK_EOS;  /* and discharge it */
 523   }
 524   else
 525     ls->t.token = llex(ls, &ls->t.seminfo);  /* read next token */
 526 }
 527
 528
 529 int luaX_lookahead (LexState *ls) {
 530   lua_assert(ls->lookahead.token == TK_EOS);
 531   ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
 532   return ls->lookahead.token;
 533 }
 534