ba8b5c17 |
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 | |