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
save(LexState * ls,int c)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
luaX_init(lua_State * L)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
luaX_token2str(LexState * ls,int token)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
txtToken(LexState * ls,int token)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
lexerror(LexState * ls,const char * msg,int token)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
luaX_syntaxerror(LexState * ls,const char * msg)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 */
luaX_newstring(LexState * ls,const char * str,size_t l)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 */
inclinenumber(LexState * ls)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
luaX_setinput(lua_State * L,LexState * ls,ZIO * z,TString * source,int firstchar)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
check_next1(LexState * ls,int c)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 */
check_next2(LexState * ls,const char * set)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 */
read_numeral(LexState * ls,SemInfo * seminfo)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 ** skip a sequence '[=*[' or ']=*]'; if sequence is well formed, return
248 ** its number of '='s; otherwise, return a negative number (-1 iff there
249 ** are no '='s after initial bracket)
250 */
skip_sep(LexState * ls)251 static int skip_sep (LexState *ls) {
252 int 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 : (-count) - 1;
261 }
262
263
read_long_string(LexState * ls,SemInfo * seminfo,int sep)264 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
265 int line = ls->linenumber; /* initial line (for error message) */
266 save_and_next(ls); /* skip 2nd '[' */
267 if (currIsNewline(ls)) /* string starts with a newline? */
268 inclinenumber(ls); /* skip it */
269 for (;;) {
270 switch (ls->current) {
271 case EOZ: { /* error */
272 const char *what = (seminfo ? "string" : "comment");
273 const char *msg = luaO_pushfstring(ls->L,
274 "unfinished long %s (starting at line %d)", what, line);
275 lexerror(ls, msg, TK_EOS);
276 break; /* to avoid warnings */
277 }
278 case ']': {
279 if (skip_sep(ls) == sep) {
280 save_and_next(ls); /* skip 2nd ']' */
281 goto endloop;
282 }
283 break;
284 }
285 case '\n': case '\r': {
286 save(ls, '\n');
287 inclinenumber(ls);
288 if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
289 break;
290 }
291 default: {
292 if (seminfo) save_and_next(ls);
293 else next(ls);
294 }
295 }
296 } endloop:
297 if (seminfo)
298 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
299 luaZ_bufflen(ls->buff) - 2*(2 + sep));
300 }
301
302
esccheck(LexState * ls,int c,const char * msg)303 static void esccheck (LexState *ls, int c, const char *msg) {
304 if (!c) {
305 if (ls->current != EOZ)
306 save_and_next(ls); /* add current to buffer for error message */
307 lexerror(ls, msg, TK_STRING);
308 }
309 }
310
311
gethexa(LexState * ls)312 static int gethexa (LexState *ls) {
313 save_and_next(ls);
314 esccheck (ls, lisxdigit(ls->current), "hexadecimal digit expected");
315 return luaO_hexavalue(ls->current);
316 }
317
318
readhexaesc(LexState * ls)319 static int readhexaesc (LexState *ls) {
320 int r = gethexa(ls);
321 r = (r << 4) + gethexa(ls);
322 luaZ_buffremove(ls->buff, 2); /* remove saved chars from buffer */
323 return r;
324 }
325
326
readutf8esc(LexState * ls)327 static unsigned long readutf8esc (LexState *ls) {
328 unsigned long r;
329 int i = 4; /* chars to be removed: '\', 'u', '{', and first digit */
330 save_and_next(ls); /* skip 'u' */
331 esccheck(ls, ls->current == '{', "missing '{'");
332 r = gethexa(ls); /* must have at least one digit */
333 while ((save_and_next(ls), lisxdigit(ls->current))) {
334 i++;
335 r = (r << 4) + luaO_hexavalue(ls->current);
336 esccheck(ls, r <= 0x10FFFF, "UTF-8 value too large");
337 }
338 esccheck(ls, ls->current == '}', "missing '}'");
339 next(ls); /* skip '}' */
340 luaZ_buffremove(ls->buff, i); /* remove saved chars from buffer */
341 return r;
342 }
343
344
utf8esc(LexState * ls)345 static void utf8esc (LexState *ls) {
346 char buff[UTF8BUFFSZ];
347 int n = luaO_utf8esc(buff, readutf8esc(ls));
348 for (; n > 0; n--) /* add 'buff' to string */
349 save(ls, buff[UTF8BUFFSZ - n]);
350 }
351
352
readdecesc(LexState * ls)353 static int readdecesc (LexState *ls) {
354 int i;
355 int r = 0; /* result accumulator */
356 for (i = 0; i < 3 && lisdigit(ls->current); i++) { /* read up to 3 digits */
357 r = 10*r + ls->current - '0';
358 save_and_next(ls);
359 }
360 esccheck(ls, r <= UCHAR_MAX, "decimal escape too large");
361 luaZ_buffremove(ls->buff, i); /* remove read digits from buffer */
362 return r;
363 }
364
365
read_string(LexState * ls,int del,SemInfo * seminfo)366 static void read_string (LexState *ls, int del, SemInfo *seminfo) {
367 save_and_next(ls); /* keep delimiter (for error messages) */
368 while (ls->current != del) {
369 switch (ls->current) {
370 case EOZ:
371 lexerror(ls, "unfinished string", TK_EOS);
372 break; /* to avoid warnings */
373 case '\n':
374 case '\r':
375 lexerror(ls, "unfinished string", TK_STRING);
376 break; /* to avoid warnings */
377 case '\\': { /* escape sequences */
378 int c; /* final character to be saved */
379 save_and_next(ls); /* keep '\\' for error messages */
380 switch (ls->current) {
381 case 'a': c = '\a'; goto read_save;
382 case 'b': c = '\b'; goto read_save;
383 case 'f': c = '\f'; goto read_save;
384 case 'n': c = '\n'; goto read_save;
385 case 'r': c = '\r'; goto read_save;
386 case 't': c = '\t'; goto read_save;
387 case 'v': c = '\v'; goto read_save;
388 case 'x': c = readhexaesc(ls); goto read_save;
389 case 'u': utf8esc(ls); goto no_save;
390 case '\n': case '\r':
391 inclinenumber(ls); c = '\n'; goto only_save;
392 case '\\': case '\"': case '\'':
393 c = ls->current; goto read_save;
394 case EOZ: goto no_save; /* will raise an error next loop */
395 case 'z': { /* zap following span of spaces */
396 luaZ_buffremove(ls->buff, 1); /* remove '\\' */
397 next(ls); /* skip the 'z' */
398 while (lisspace(ls->current)) {
399 if (currIsNewline(ls)) inclinenumber(ls);
400 else next(ls);
401 }
402 goto no_save;
403 }
404 default: {
405 esccheck(ls, lisdigit(ls->current), "invalid escape sequence");
406 c = readdecesc(ls); /* digital escape '\ddd' */
407 goto only_save;
408 }
409 }
410 read_save:
411 next(ls);
412 /* go through */
413 only_save:
414 luaZ_buffremove(ls->buff, 1); /* remove '\\' */
415 save(ls, c);
416 /* go through */
417 no_save: break;
418 }
419 default:
420 save_and_next(ls);
421 }
422 }
423 save_and_next(ls); /* skip delimiter */
424 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
425 luaZ_bufflen(ls->buff) - 2);
426 }
427
428
llex(LexState * ls,SemInfo * seminfo)429 static int llex (LexState *ls, SemInfo *seminfo) {
430 luaZ_resetbuffer(ls->buff);
431 for (;;) {
432 switch (ls->current) {
433 case '\n': case '\r': { /* line breaks */
434 inclinenumber(ls);
435 break;
436 }
437 case ' ': case '\f': case '\t': case '\v': { /* spaces */
438 next(ls);
439 break;
440 }
441 case '-': { /* '-' or '--' (comment) */
442 next(ls);
443 if (ls->current != '-') return '-';
444 /* else is a comment */
445 next(ls);
446 if (ls->current == '[') { /* long comment? */
447 int sep = skip_sep(ls);
448 luaZ_resetbuffer(ls->buff); /* 'skip_sep' may dirty the buffer */
449 if (sep >= 0) {
450 read_long_string(ls, NULL, sep); /* skip long comment */
451 luaZ_resetbuffer(ls->buff); /* previous call may dirty the buff. */
452 break;
453 }
454 }
455 /* else short comment */
456 while (!currIsNewline(ls) && ls->current != EOZ)
457 next(ls); /* skip until end of line (or end of file) */
458 break;
459 }
460 case '[': { /* long string or simply '[' */
461 int sep = skip_sep(ls);
462 if (sep >= 0) {
463 read_long_string(ls, seminfo, sep);
464 return TK_STRING;
465 }
466 else if (sep != -1) /* '[=...' missing second bracket */
467 lexerror(ls, "invalid long string delimiter", TK_STRING);
468 return '[';
469 }
470 case '=': {
471 next(ls);
472 if (check_next1(ls, '=')) return TK_EQ;
473 else return '=';
474 }
475 case '<': {
476 next(ls);
477 if (check_next1(ls, '=')) return TK_LE;
478 else if (check_next1(ls, '<')) return TK_SHL;
479 else return '<';
480 }
481 case '>': {
482 next(ls);
483 if (check_next1(ls, '=')) return TK_GE;
484 else if (check_next1(ls, '>')) return TK_SHR;
485 else return '>';
486 }
487 case '/': {
488 next(ls);
489 if (check_next1(ls, '/')) return TK_IDIV;
490 else return '/';
491 }
492 case '~': {
493 next(ls);
494 if (check_next1(ls, '=')) return TK_NE;
495 else return '~';
496 }
497 case ':': {
498 next(ls);
499 if (check_next1(ls, ':')) return TK_DBCOLON;
500 else return ':';
501 }
502 case '"': case '\'': { /* short literal strings */
503 read_string(ls, ls->current, seminfo);
504 return TK_STRING;
505 }
506 case '.': { /* '.', '..', '...', or number */
507 save_and_next(ls);
508 if (check_next1(ls, '.')) {
509 if (check_next1(ls, '.'))
510 return TK_DOTS; /* '...' */
511 else return TK_CONCAT; /* '..' */
512 }
513 else if (!lisdigit(ls->current)) return '.';
514 else return read_numeral(ls, seminfo);
515 }
516 case '0': case '1': case '2': case '3': case '4':
517 case '5': case '6': case '7': case '8': case '9': {
518 return read_numeral(ls, seminfo);
519 }
520 case EOZ: {
521 return TK_EOS;
522 }
523 default: {
524 if (lislalpha(ls->current)) { /* identifier or reserved word? */
525 TString *ts;
526 do {
527 save_and_next(ls);
528 } while (lislalnum(ls->current));
529 ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
530 luaZ_bufflen(ls->buff));
531 seminfo->ts = ts;
532 if (isreserved(ts)) /* reserved word? */
533 return ts->extra - 1 + FIRST_RESERVED;
534 else {
535 return TK_NAME;
536 }
537 }
538 else { /* single-char tokens (+ - / ...) */
539 int c = ls->current;
540 next(ls);
541 return c;
542 }
543 }
544 }
545 }
546 }
547
548
luaX_next(LexState * ls)549 void luaX_next (LexState *ls) {
550 ls->lastline = ls->linenumber;
551 if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
552 ls->t = ls->lookahead; /* use this one */
553 ls->lookahead.token = TK_EOS; /* and discharge it */
554 }
555 else
556 ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */
557 }
558
559
luaX_lookahead(LexState * ls)560 int luaX_lookahead (LexState *ls) {
561 lua_assert(ls->lookahead.token == TK_EOS);
562 ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
563 return ls->lookahead.token;
564 }
565
566