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1/*
2** $Id: llex.c,v 2.20 2006/03/09 18:14:31 roberto Exp $
3** Lexical Analyzer
4** See Copyright Notice in lua.h
5*/
6
7
8#include <ctype.h>
9#include <locale.h>
10#include <string.h>
11
12#define llex_c
13#define LUA_CORE
14
15#include "lua.h"
16
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
33#define currIsNewline(ls)(ls->current == '\n' || ls->current == '\r')
34
35
36/* ORDER RESERVED */
37const char *const luaX_tokens [] = {
38 "and", "break", "do", "else", "elseif",
39 "end", "false", "for", "function", "if",
40 "in", "local", "nil", "not", "or", "repeat",
41 "return", "then", "true", "until", "while",
42 "..", "...", "==", ">=", "<=", "~=",
43 "<number>", "<name>", "<string>", "<eof>",
44 NULL
45};
46
47
48#define save_and_next(ls) (save(ls, ls->current), next(ls))
49
50
51static void save (LexState *ls, int c) {
52 Mbuffer *b = ls->buff;
53 if (b->n + 1 > b->buffsize) {
54 size_t newsize;
55 if (b->buffsize >= MAX_SIZET/2)
56 luaX_lexerror(ls, "lexical element too long", 0);
57 newsize = b->buffsize * 2;
58 luaZ_resizebuffer(ls->L, b, newsize);
59 }
60 b->buffer[b->n++] = cast(char, c);
61}
62
63
64void luaX_init (lua_State *L) {
65 int i;
66 for (i=0; i<NUM_RESERVED; i++) {
67 TString *ts = luaS_new(L, luaX_tokens[i]);
68 luaS_fix(ts); /* reserved words are never collected */
69 lua_assert(strlen(luaX_tokens[i])+1 <= TOKEN_LEN);
70 ts->tsv.reserved = cast_byte(i+1); /* reserved word */
71 }
72}
73
74
75#define MAXSRC 80
76
77
78const char *luaX_token2str (LexState *ls, int token) {
79 if (token < FIRST_RESERVED) {
80 lua_assert(token == cast(unsigned char, token));
81 return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :
82 luaO_pushfstring(ls->L, "%c", token);
83 }
84 else
85 return luaX_tokens[token-FIRST_RESERVED];
86}
87
88
89static const char *txtToken (LexState *ls, int token) {
90 switch (token) {
91 case TK_NAME:
92 case TK_STRING:
93 case TK_NUMBER:
94 save(ls, '\0');
95 return luaZ_buffer(ls->buff);
96 default:
97 return luaX_token2str(ls, token);
98 }
99}
100
101
102void luaX_lexerror (LexState *ls, const char *msg, int token) {
103 char buff[MAXSRC];
104 luaO_chunkid(buff, getstr(ls->source), MAXSRC);
105 msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
106 if (token)
107 luaO_pushfstring(ls->L, "%s near " LUA_QS, msg, txtToken(ls, token));
108 luaD_throw(ls->L, LUA_ERRSYNTAX);
109}
110
111
112void luaX_syntaxerror (LexState *ls, const char *msg) {
113 luaX_lexerror(ls, msg, ls->t.token);
114}
115
116
117TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
118 lua_State *L = ls->L;
119 TString *ts = luaS_newlstr(L, str, l);
120 TValue *o = luaH_setstr(L, ls->fs->h, ts); /* entry for `str' */
121 if (ttisnil(o))
122 setbvalue(o, 1); /* make sure `str' will not be collected */
123 return ts;
124}
125
126
127static void inclinenumber (LexState *ls) {
128 int old = ls->current;
129 lua_assert(currIsNewline(ls));
130 next(ls); /* skip `\n' or `\r' */
131 if (currIsNewline(ls) && ls->current != old)
132 next(ls); /* skip `\n\r' or `\r\n' */
133 if (++ls->linenumber >= MAX_INT)
134 luaX_syntaxerror(ls, "chunk has too many lines");
135}
136
137
138void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
139 ls->decpoint = '.';
140 ls->L = L;
141 ls->lookahead.token = TK_EOS; /* no look-ahead token */
142 ls->z = z;
143 ls->fs = NULL;
144 ls->linenumber = 1;
145 ls->lastline = 1;
146 ls->source = source;
147 luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */
148 next(ls); /* read first char */
149}
150
151
152
153/*
154** =======================================================
155** LEXICAL ANALYZER
156** =======================================================
157*/
158
159
160
161static int check_next (LexState *ls, const char *set) {
162 if (!strchr(set, ls->current))
163 return 0;
164 save_and_next(ls);
165 return 1;
166}
167
168
169static void buffreplace (LexState *ls, char from, char to) {
170 size_t n = luaZ_bufflen(ls->buff);
171 char *p = luaZ_buffer(ls->buff);
172 while (n--)
173 if (p[n] == from) p[n] = to;
174}
175
176
177static void trydecpoint (LexState *ls, SemInfo *seminfo) {
178 /* format error: try to update decimal point separator */
179 struct lconv *cv = localeconv();
180 char old = ls->decpoint;
181 ls->decpoint = (cv ? cv->decimal_point[0] : '.');
182 buffreplace(ls, old, ls->decpoint); /* try updated decimal separator */
183 if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) {
184 /* format error with correct decimal point: no more options */
185 buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */
186 luaX_lexerror(ls, "malformed number", TK_NUMBER);
187 }
188}
189
190
191/* LUA_NUMBER */
192static void read_numeral (LexState *ls, SemInfo *seminfo) {
193 lua_assert(isdigit(ls->current));
194 do {
195 save_and_next(ls);
196 } while (isdigit(ls->current) || ls->current == '.');
197 if (check_next(ls, "Ee")) /* `E'? */
198 check_next(ls, "+-"); /* optional exponent sign */
199 while (isalnum(ls->current) || ls->current == '_')
200 save_and_next(ls);
201 save(ls, '\0');
202 buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */
203 if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) /* format error? */
204 trydecpoint(ls, seminfo); /* try to update decimal point separator */
205}
206
207
208static int skip_sep (LexState *ls) {
209 int count = 0;
210 int s = ls->current;
211 lua_assert(s == '[' || s == ']');
212 save_and_next(ls);
213 while (ls->current == '=') {
214 save_and_next(ls);
215 count++;
216 }
217 return (ls->current == s) ? count : (-count) - 1;
218}
219
220
221static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
222 int cont = 0;
223 (void)(cont); /* avoid warnings when `cont' is not used */
224 save_and_next(ls); /* skip 2nd `[' */
225 if (currIsNewline(ls)) /* string starts with a newline? */
226 inclinenumber(ls); /* skip it */
227 for (;;) {
228 switch (ls->current) {
229 case EOZ:
230 luaX_lexerror(ls, (seminfo) ? "unfinished long string" :
231 "unfinished long comment", TK_EOS);
232 break; /* to avoid warnings */
233#if defined(LUA_COMPAT_LSTR)
234 case '[': {
235 if (skip_sep(ls) == sep) {
236 save_and_next(ls); /* skip 2nd `[' */
237 cont++;
238#if LUA_COMPAT_LSTR == 1
239 if (sep == 0)
240 luaX_lexerror(ls, "nesting of [[...]] is deprecated", '[');
241#endif
242 }
243 break;
244 }
245#endif
246 case ']': {
247 if (skip_sep(ls) == sep) {
248 save_and_next(ls); /* skip 2nd `]' */
249#if defined(LUA_COMPAT_LSTR) && LUA_COMPAT_LSTR == 2
250 cont--;
251 if (sep == 0 && cont >= 0) break;
252#endif
253 goto endloop;
254 }
255 break;
256 }
257 case '\n':
258 case '\r': {
259 save(ls, '\n');
260 inclinenumber(ls);
261 if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
262 break;
263 }
264 default: {
265 if (seminfo) save_and_next(ls);
266 else next(ls);
267 }
268 }
269 } endloop:
270 if (seminfo)
271 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
272 luaZ_bufflen(ls->buff) - 2*(2 + sep));
273}
274
275
276static void read_string (LexState *ls, int del, SemInfo *seminfo) {
277 save_and_next(ls);
278 while (ls->current != del) {
279 switch (ls->current) {
280 case EOZ:
281 luaX_lexerror(ls, "unfinished string", TK_EOS);
282 continue; /* to avoid warnings */
283 case '\n':
284 case '\r':
285 luaX_lexerror(ls, "unfinished string", TK_STRING);
286 continue; /* to avoid warnings */
287 case '\\': {
288 int c;
289 next(ls); /* do not save the `\' */
290 switch (ls->current) {
291 case 'a': c = '\a'; break;
292 case 'b': c = '\b'; break;
293 case 'f': c = '\f'; break;
294 case 'n': c = '\n'; break;
295 case 'r': c = '\r'; break;
296 case 't': c = '\t'; break;
297 case 'v': c = '\v'; break;
298 case '\n': /* go through */
299 case '\r': save(ls, '\n'); inclinenumber(ls); continue;
300 case EOZ: continue; /* will raise an error next loop */
301 default: {
302 if (!isdigit(ls->current))
303 save_and_next(ls); /* handles \\, \", \', and \? */
304 else { /* \xxx */
305 int i = 0;
306 c = 0;
307 do {
308 c = 10*c + (ls->current-'0');
309 next(ls);
310 } while (++i<3 && isdigit(ls->current));
311 if (c > UCHAR_MAX)
312 luaX_lexerror(ls, "escape sequence too large", TK_STRING);
313 save(ls, c);
314 }
315 continue;
316 }
317 }
318 save(ls, c);
319 next(ls);
320 continue;
321 }
322 default:
323 save_and_next(ls);
324 }
325 }
326 save_and_next(ls); /* skip delimiter */
327 seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
328 luaZ_bufflen(ls->buff) - 2);
329}
330
331
332static int llex (LexState *ls, SemInfo *seminfo) {
333 luaZ_resetbuffer(ls->buff);
334 for (;;) {
335 switch (ls->current) {
336 case '\n':
337 case '\r': {
338 inclinenumber(ls);
339 continue;
340 }
341 case '-': {
342 next(ls);
343 if (ls->current != '-') return '-';
344 /* else is a comment */
345 next(ls);
346 if (ls->current == '[') {
347 int sep = skip_sep(ls);
348 luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */
349 if (sep >= 0) {
350 read_long_string(ls, NULL, sep); /* long comment */
351 luaZ_resetbuffer(ls->buff);
352 continue;
353 }
354 }
355 /* else short comment */
356 while (!currIsNewline(ls) && ls->current != EOZ)
357 next(ls);
358 continue;
359 }
360 case '[': {
361 int sep = skip_sep(ls);
362 if (sep >= 0) {
363 read_long_string(ls, seminfo, sep);
364 return TK_STRING;
365 }
366 else if (sep == -1) return '[';
367 else luaX_lexerror(ls, "invalid long string delimiter", TK_STRING);
368 }
369 case '=': {
370 next(ls);
371 if (ls->current != '=') return '=';
372 else { next(ls); return TK_EQ; }
373 }
374 case '<': {
375 next(ls);
376 if (ls->current != '=') return '<';
377 else { next(ls); return TK_LE; }
378 }
379 case '>': {
380 next(ls);
381 if (ls->current != '=') return '>';
382 else { next(ls); return TK_GE; }
383 }
384 case '~': {
385 next(ls);
386 if (ls->current != '=') return '~';
387 else { next(ls); return TK_NE; }
388 }
389 case '"':
390 case '\'': {
391 read_string(ls, ls->current, seminfo);
392 return TK_STRING;
393 }
394 case '.': {
395 save_and_next(ls);
396 if (check_next(ls, ".")) {
397 if (check_next(ls, "."))
398 return TK_DOTS; /* ... */
399 else return TK_CONCAT; /* .. */
400 }
401 else if (!isdigit(ls->current)) return '.';
402 else {
403 read_numeral(ls, seminfo);
404 return TK_NUMBER;
405 }
406 }
407 case EOZ: {
408 return TK_EOS;
409 }
410 default: {
411 if (isspace(ls->current)) {
412 lua_assert(!currIsNewline(ls));
413 next(ls);
414 continue;
415 }
416 else if (isdigit(ls->current)) {
417 read_numeral(ls, seminfo);
418 return TK_NUMBER;
419 }
420 else if (isalpha(ls->current) || ls->current == '_') {
421 /* identifier or reserved word */
422 TString *ts;
423 do {
424 save_and_next(ls);
425 } while (isalnum(ls->current) || ls->current == '_');
426 ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
427 luaZ_bufflen(ls->buff));
428 if (ts->tsv.reserved > 0) /* reserved word? */
429 return ts->tsv.reserved - 1 + FIRST_RESERVED;
430 else {
431 seminfo->ts = ts;
432 return TK_NAME;
433 }
434 }
435 else {
436 int c = ls->current;
437 next(ls);
438 return c; /* single-char tokens (+ - / ...) */
439 }
440 }
441 }
442 }
443}
444
445
446void luaX_next (LexState *ls) {
447 ls->lastline = ls->linenumber;
448 if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
449 ls->t = ls->lookahead; /* use this one */
450 ls->lookahead.token = TK_EOS; /* and discharge it */
451 }
452 else
453 ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */
454}
455
456
457void luaX_lookahead (LexState *ls) {
458 lua_assert(ls->lookahead.token == TK_EOS);
459 ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
460}
461

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