source: trunk/src/lua/llex.c @ 2542

Last change on this file since 2542 was 2542, checked in by sam, 8 years ago

lua: compilation fixes for non-quite-POSIX platforms.

File size: 14.8 KB
Line 
1/*
2** $Id: llex.c,v 2.61 2012/01/23 23:05:51 roberto Exp $
3** Lexical Analyzer
4** See Copyright Notice in lua.h
5*/
6
7#if defined HAVE_CONFIG_H // LOL BEGIN
8#   include "config.h"
9#endif // LOL END
10
11#include <locale.h>
12#include <string.h>
13
14#define llex_c
15#define LUA_CORE
16
17#include "lua.h"
18
19#include "lctype.h"
20#include "ldo.h"
21#include "llex.h"
22#include "lobject.h"
23#include "lparser.h"
24#include "lstate.h"
25#include "lstring.h"
26#include "ltable.h"
27#include "lzio.h"
28
29
30
31#define next(ls) (ls->current = zgetc(ls->z))
32
33
34
35#define currIsNewline(ls)       (ls->current == '\n' || ls->current == '\r')
36
37
38/* ORDER RESERVED */
39static const char *const luaX_tokens [] = {
40    "and", "break", "do", "else", "elseif",
41    "end", "false", "for", "function", "goto", "if",
42    "in", "local", "nil", "not", "or", "repeat",
43    "return", "then", "true", "until", "while",
44    "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
45    "<number>", "<name>", "<string>"
46};
47
48
49#define save_and_next(ls) (save(ls, ls->current), next(ls))
50
51
52static l_noret lexerror (LexState *ls, const char *msg, int token);
53
54
55static void save (LexState *ls, int c) {
56  Mbuffer *b = ls->buff;
57  if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
58    size_t newsize;
59    if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
60      lexerror(ls, "lexical element too long", 0);
61    newsize = luaZ_sizebuffer(b) * 2;
62    luaZ_resizebuffer(ls->L, b, newsize);
63  }
64  b->buffer[luaZ_bufflen(b)++] = cast(char, c);
65}
66
67
68void luaX_init (lua_State *L) {
69  int i;
70  for (i=0; i<NUM_RESERVED; i++) {
71    TString *ts = luaS_new(L, luaX_tokens[i]);
72    luaS_fix(ts);  /* reserved words are never collected */
73    ts->tsv.extra = cast_byte(i+1);  /* reserved word */
74  }
75}
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 (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
82                              luaO_pushfstring(ls->L, "char(%d)", token);
83  }
84  else {
85    const char *s = luaX_tokens[token - FIRST_RESERVED];
86    if (token < TK_EOS)
87      return luaO_pushfstring(ls->L, LUA_QS, s);
88    else
89      return s;
90  }
91}
92
93
94static const char *txtToken (LexState *ls, int token) {
95  switch (token) {
96    case TK_NAME:
97    case TK_STRING:
98    case TK_NUMBER:
99      save(ls, '\0');
100      return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
101    default:
102      return luaX_token2str(ls, token);
103  }
104}
105
106
107static l_noret lexerror (LexState *ls, const char *msg, int token) {
108  char buff[LUA_IDSIZE];
109  luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
110  msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
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
117l_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 function's table so that
124** it will not be collected until the end of the function's compilation
125** (by that time it should be anchored in function's prototype)
126*/
127TString *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->fs->h, L->top - 1);
133  if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
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  L->top--;  /* remove string from stack */
140  return ts;
141}
142
143
144/*
145** increment line number and skips newline sequence (any of
146** \n, \r, \n\r, or \r\n)
147*/
148static void inclinenumber (LexState *ls) {
149  int old = ls->current;
150  lua_assert(currIsNewline(ls));
151  next(ls);  /* skip `\n' or `\r' */
152  if (currIsNewline(ls) && ls->current != old)
153    next(ls);  /* skip `\n\r' or `\r\n' */
154  if (++ls->linenumber >= MAX_INT)
155    luaX_syntaxerror(ls, "chunk has too many lines");
156}
157
158
159void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
160                    int firstchar) {
161  ls->decpoint = '.';
162  ls->L = L;
163  ls->current = firstchar;
164  ls->lookahead.token = TK_EOS;  /* no look-ahead token */
165  ls->z = z;
166  ls->fs = NULL;
167  ls->linenumber = 1;
168  ls->lastline = 1;
169  ls->source = source;
170  ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
171  luaS_fix(ls->envn);  /* never collect this name */
172  luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
173}
174
175
176
177/*
178** =======================================================
179** LEXICAL ANALYZER
180** =======================================================
181*/
182
183
184
185static int check_next (LexState *ls, const char *set) {
186  if (ls->current == '\0' || !strchr(set, ls->current))
187    return 0;
188  save_and_next(ls);
189  return 1;
190}
191
192
193/*
194** change all characters 'from' in buffer to 'to'
195*/
196static void buffreplace (LexState *ls, char from, char to) {
197  size_t n = luaZ_bufflen(ls->buff);
198  char *p = luaZ_buffer(ls->buff);
199  while (n--)
200    if (p[n] == from) p[n] = to;
201}
202
203
204#if !defined(getlocaledecpoint)
205#define getlocaledecpoint()     (localeconv()->decimal_point[0])
206#endif
207
208
209#define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
210
211/*
212** in case of format error, try to change decimal point separator to
213** the one defined in the current locale and check again
214*/
215static void trydecpoint (LexState *ls, SemInfo *seminfo) {
216  char old = ls->decpoint;
217  ls->decpoint = getlocaledecpoint();
218  buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
219  if (!buff2d(ls->buff, &seminfo->r)) {
220    /* format error with correct decimal point: no more options */
221    buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
222    lexerror(ls, "malformed number", TK_NUMBER);
223  }
224}
225
226
227/* LUA_NUMBER */
228/*
229** this function is quite liberal in what it accepts, as 'luaO_str2d'
230** will reject ill-formed numerals.
231*/
232static void read_numeral (LexState *ls, SemInfo *seminfo) {
233  const char *expo = "Ee";
234  int first = ls->current;
235  lua_assert(lisdigit(ls->current));
236  save_and_next(ls);
237  if (first == '0' && check_next(ls, "Xx"))  /* hexadecimal? */
238    expo = "Pp";
239  for (;;) {
240    if (check_next(ls, expo))  /* exponent part? */
241      check_next(ls, "+-");  /* optional exponent sign */
242    if (lisxdigit(ls->current) || ls->current == '.')
243      save_and_next(ls);
244    else  break;
245  }
246  save(ls, '\0');
247  buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
248  if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
249    trydecpoint(ls, seminfo); /* try to update decimal point separator */
250}
251
252
253/*
254** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
255** -1 if sequence is malformed
256*/
257static int skip_sep (LexState *ls) {
258  int count = 0;
259  int s = ls->current;
260  lua_assert(s == '[' || s == ']');
261  save_and_next(ls);
262  while (ls->current == '=') {
263    save_and_next(ls);
264    count++;
265  }
266  return (ls->current == s) ? count : (-count) - 1;
267}
268
269
270static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
271  save_and_next(ls);  /* skip 2nd `[' */
272  if (currIsNewline(ls))  /* string starts with a newline? */
273    inclinenumber(ls);  /* skip it */
274  for (;;) {
275    switch (ls->current) {
276      case EOZ:
277        lexerror(ls, (seminfo) ? "unfinished long string" :
278                                 "unfinished long comment", TK_EOS);
279        break;  /* to avoid warnings */
280      case ']': {
281        if (skip_sep(ls) == sep) {
282          save_and_next(ls);  /* skip 2nd `]' */
283          goto endloop;
284        }
285        break;
286      }
287      case '\n': case '\r': {
288        save(ls, '\n');
289        inclinenumber(ls);
290        if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
291        break;
292      }
293      default: {
294        if (seminfo) save_and_next(ls);
295        else next(ls);
296      }
297    }
298  } endloop:
299  if (seminfo)
300    seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
301                                     luaZ_bufflen(ls->buff) - 2*(2 + sep));
302}
303
304
305static void escerror (LexState *ls, int *c, int n, const char *msg) {
306  int i;
307  luaZ_resetbuffer(ls->buff);  /* prepare error message */
308  save(ls, '\\');
309  for (i = 0; i < n && c[i] != EOZ; i++)
310    save(ls, c[i]);
311  lexerror(ls, msg, TK_STRING);
312}
313
314
315static int readhexaesc (LexState *ls) {
316  int c[3], i;  /* keep input for error message */
317  int r = 0;  /* result accumulator */
318  c[0] = 'x';  /* for error message */
319  for (i = 1; i < 3; i++) {  /* read two hexa digits */
320    c[i] = next(ls);
321    if (!lisxdigit(c[i]))
322      escerror(ls, c, i + 1, "hexadecimal digit expected");
323    r = (r << 4) + luaO_hexavalue(c[i]);
324  }
325  return r;
326}
327
328
329static int readdecesc (LexState *ls) {
330  int c[3], i;
331  int r = 0;  /* result accumulator */
332  for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
333    c[i] = ls->current;
334    r = 10*r + c[i] - '0';
335    next(ls);
336  }
337  if (r > UCHAR_MAX)
338    escerror(ls, c, i, "decimal escape too large");
339  return r;
340}
341
342
343static void read_string (LexState *ls, int del, SemInfo *seminfo) {
344  save_and_next(ls);  /* keep delimiter (for error messages) */
345  while (ls->current != del) {
346    switch (ls->current) {
347      case EOZ:
348        lexerror(ls, "unfinished string", TK_EOS);
349        break;  /* to avoid warnings */
350      case '\n':
351      case '\r':
352        lexerror(ls, "unfinished string", TK_STRING);
353        break;  /* to avoid warnings */
354      case '\\': {  /* escape sequences */
355        int c;  /* final character to be saved */
356        next(ls);  /* do not save the `\' */
357        switch (ls->current) {
358          case 'a': c = '\a'; goto read_save;
359          case 'b': c = '\b'; goto read_save;
360          case 'f': c = '\f'; goto read_save;
361          case 'n': c = '\n'; goto read_save;
362          case 'r': c = '\r'; goto read_save;
363          case 't': c = '\t'; goto read_save;
364          case 'v': c = '\v'; goto read_save;
365          case 'x': c = readhexaesc(ls); goto read_save;
366          case '\n': case '\r':
367            inclinenumber(ls); c = '\n'; goto only_save;
368          case '\\': case '\"': case '\'':
369            c = ls->current; goto read_save;
370          case EOZ: goto no_save;  /* will raise an error next loop */
371          case 'z': {  /* zap following span of spaces */
372            next(ls);  /* skip the 'z' */
373            while (lisspace(ls->current)) {
374              if (currIsNewline(ls)) inclinenumber(ls);
375              else next(ls);
376            }
377            goto no_save;
378          }
379          default: {
380            if (!lisdigit(ls->current))
381              escerror(ls, &ls->current, 1, "invalid escape sequence");
382            /* digital escape \ddd */
383            c = readdecesc(ls);
384            goto only_save;
385          }
386        }
387       read_save: next(ls);  /* read next character */
388       only_save: save(ls, c);  /* save 'c' */
389       no_save: break;
390      }
391      default:
392        save_and_next(ls);
393    }
394  }
395  save_and_next(ls);  /* skip delimiter */
396  seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
397                                   luaZ_bufflen(ls->buff) - 2);
398}
399
400
401static int llex (LexState *ls, SemInfo *seminfo) {
402  luaZ_resetbuffer(ls->buff);
403  for (;;) {
404    switch (ls->current) {
405      case '\n': case '\r': {  /* line breaks */
406        inclinenumber(ls);
407        break;
408      }
409      case ' ': case '\f': case '\t': case '\v': {  /* spaces */
410        next(ls);
411        break;
412      }
413      case '-': {  /* '-' or '--' (comment) */
414        next(ls);
415        if (ls->current != '-') return '-';
416        /* else is a comment */
417        next(ls);
418        if (ls->current == '[') {  /* long comment? */
419          int sep = skip_sep(ls);
420          luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
421          if (sep >= 0) {
422            read_long_string(ls, NULL, sep);  /* skip long comment */
423            luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
424            break;
425          }
426        }
427        /* else short comment */
428        while (!currIsNewline(ls) && ls->current != EOZ)
429          next(ls);  /* skip until end of line (or end of file) */
430        break;
431      }
432      case '[': {  /* long string or simply '[' */
433        int sep = skip_sep(ls);
434        if (sep >= 0) {
435          read_long_string(ls, seminfo, sep);
436          return TK_STRING;
437        }
438        else if (sep == -1) return '[';
439        else lexerror(ls, "invalid long string delimiter", TK_STRING);
440      }
441      case '=': {
442        next(ls);
443        if (ls->current != '=') return '=';
444        else { next(ls); return TK_EQ; }
445      }
446      case '<': {
447        next(ls);
448        if (ls->current != '=') return '<';
449        else { next(ls); return TK_LE; }
450      }
451      case '>': {
452        next(ls);
453        if (ls->current != '=') return '>';
454        else { next(ls); return TK_GE; }
455      }
456      case '~': {
457        next(ls);
458        if (ls->current != '=') return '~';
459        else { next(ls); return TK_NE; }
460      }
461      case ':': {
462        next(ls);
463        if (ls->current != ':') return ':';
464        else { next(ls); return TK_DBCOLON; }
465      }
466      case '"': case '\'': {  /* short literal strings */
467        read_string(ls, ls->current, seminfo);
468        return TK_STRING;
469      }
470      case '.': {  /* '.', '..', '...', or number */
471        save_and_next(ls);
472        if (check_next(ls, ".")) {
473          if (check_next(ls, "."))
474            return TK_DOTS;   /* '...' */
475          else return TK_CONCAT;   /* '..' */
476        }
477        else if (!lisdigit(ls->current)) return '.';
478        /* else go through */
479      }
480      case '0': case '1': case '2': case '3': case '4':
481      case '5': case '6': case '7': case '8': case '9': {
482        read_numeral(ls, seminfo);
483        return TK_NUMBER;
484      }
485      case EOZ: {
486        return TK_EOS;
487      }
488      default: {
489        if (lislalpha(ls->current)) {  /* identifier or reserved word? */
490          TString *ts;
491          do {
492            save_and_next(ls);
493          } while (lislalnum(ls->current));
494          ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
495                                  luaZ_bufflen(ls->buff));
496          seminfo->ts = ts;
497          if (isreserved(ts))  /* reserved word? */
498            return ts->tsv.extra - 1 + FIRST_RESERVED;
499          else {
500            return TK_NAME;
501          }
502        }
503        else {  /* single-char tokens (+ - / ...) */
504          int c = ls->current;
505          next(ls);
506          return c;
507        }
508      }
509    }
510  }
511}
512
513
514void luaX_next (LexState *ls) {
515  ls->lastline = ls->linenumber;
516  if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
517    ls->t = ls->lookahead;  /* use this one */
518    ls->lookahead.token = TK_EOS;  /* and discharge it */
519  }
520  else
521    ls->t.token = llex(ls, &ls->t.seminfo);  /* read next token */
522}
523
524
525int luaX_lookahead (LexState *ls) {
526  lua_assert(ls->lookahead.token == TK_EOS);
527  ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
528  return ls->lookahead.token;
529}
530
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